The Curonian Lagoon of the Baltic Sea is one of the most highly eutrophic water bodies (hypertrophic type) and is of great fishery and recreational importance. The coastal zone has the most important function in the ecosystem of the lagoon. Monthly studies in January–October 2022 showed the absence of algal “hyperblooming”. Based on the results of a detailed spatial study in August 2022 along the Curonian Spit in 4 sections, hydrobiological and hydrochemical characteristics of the “background” state of the coastal zone were obtained without the adverse effects of Cyanobacteria blooming. The oxygen content (80–160 % saturation) was favorable for hydrobionts, while the values of BOD5 and ammonium nitrogen indicated a slight accumulation and decomposition of organic matter (including algae biomass). The concentration of chlorophyll "a" was 15–43 μg/l, and abundance of saprophytic bacteria was 9–35 thousand CFU/ml. Increased values of phosphates and chlorophyll in the area of the set. Lesnoy, possibly indicate local anthropogenic pollution. In the coastal zone in 2022, the indicators of the ecological state corresponded mainly to eutrophic, α-mesosaprobity, low or moderately polluted waters in terms of the concentration of chlorophyll “a” and the abundance of saprophytic bacteria. The water quality was significantly higher than was observed in some years during the “hyperblooming” of the lagoon, when these indicators corresponded to the maximum hypertrophic and hypersaprobic levels that adversely affect the ecosystem (disease and death of aquatic organisms). Consequently, in the years of absence of summer algal “hyperblooming”, the coastal zone is characterized by favorable conditions for fishery and recreational use in the area of the Curonian Spit National Park.

Within the framework of the scientific article, the task of determining the quality and availability of water supplied from natural sources has been foregrounded. The basis for the development of innovative methods for the identification of water from natural waters on the example of Lake Baikal has been considered. Organoleptic and microbiological indicators of water from Lake Baikal are given. A brief overview of methods for determining the quality of natural water is made, from which it follows that determination of the chemical composition according to GOST is not a unique property of water from natural sources. The unique property of bacteria to form restriction endonuclease (ER) enzymes (restrictases) is considered as a reaction to the ingress of extraneous microflora into the environment. This method, widely used in scientific research, is practically not implemented as a control of the quality and availability of water when it is bottled for sale. We found that bacterial strains with ER enzymes were isolated in the samples of water taken in areas of anthropogenic influence. In water samples taken in clean background areas (pelagic lakes, deep-sea sediments), bacteria with the enzyme ER have not been detected. This property of bacteria is to form ER enzymes as protection against allochthonous (extraneous) microflora. This article substantiates the fact that detection of ER enzymes in bacterial strains is evidence that the water has been taken either in areas where the foreign microflora enters, or the water is not from a natural source – Lake Baikal. This method makes it possible to determine the quality and authenticity of Baikal drinking water and to exclude counterfeits of natural water on the market.

The paper presents the results of experimental studies related to the determination (calculation) of the aggregate resistance of a floating anchor. As you know, a floating anchor is a device that keeps a small vessel in place in strong currents, wind, high waves. In our study, a floating anchor is necessary to assess the available thrust of the vessel in the conditions of the landfill, i.e. its towing and determination of the speed of trawling (towing) by a motor boat model "Oka-4". The experiments were carried out in the water channel of LLC "Fishering Service" in Kaliningrad and at the Berezovsky quarry test site, which is located in the Gvardeisk district of the Kaliningrad region. Fourth-year undergraduate students took part in the experimental research. They used part of the experimental data obtained to write their final qualifying theses. The experimental studies carried out by us made it possible to substantiate the traction characteristics of two paired motor boats "Oka-4" with engines, each with a power of 25 hp. The studies were carried out under both laboratory and other environment conditions being equal. Trawling of such a prey as vendace (Coregonus albula) in Lake Vishtynetskoye is one of the priority tasks for the Kaliningrad region in the field of fishing. This type of fishery is important from the point of view of substantiating the total allowable catch (TAC) for catching vendace, since the designed trawl for catching this fish species will be operated and will significantly increase the catch of a valuable species of hydrobionts in Lake Vishtynetskoye.

Organic waste from livestock and poultry complexes (manure, manure drains, manure) should be environmentally safe for the environment. Negative environmental consequences of the emission of N-containing compounds include changes in the biodiversity of flora and fauna of water bodies, chemical and microbial degradation of arable lands of agricultural lands and atmospheric air pollution, including odorous. When storing organic waste in lagoons for 6–12 months, the emission of N-containing compounds, including ammonia, occurs. Microbiological processes in manure runoff occur with the participation of microorganisms-ammonifiers. There are Pseudomonas, Bacillus, Clostridium, Proteus. In the course of our research, it has been found that Peptostreptococcus anaerobius ammonifiers dominate in fresh manure drains. The quantitative and qualitative composition of ammonifiers varies depending on the terms and conditions of storage (acidification of manure drains). During storage, the largest number of ammonifiers is reached on the 14th day. On the 7th day, the prevalence of Clostridium spp. was noted, and on the 14th day- E. Coli prevailed. Acidification of manure effluents with a 10 % solution of sulfuric acid to a pH of 5.3 ± 0.2 significantly reduces the number of microorganisms-ammonifiers by 98.89 % on the 7th and 89.05 % and 14th days, respectively, in comparison with the initial values. The activity of Proteus spp. is completely suppressed, which leads to the complete disappearance of the microorganism from the manure drains. The most resistant to acidification were Clostridium spp. Application of the technology of acidification of manure effluents will reduce the negative impact of pig breeding enterprises on ecosystems due to a significant reduction in NH3 entering the environment from manure effluents.

Currently, the multi-tonnage waste – meal – remaining after processing the fruits of buckthorn buckthorn (Hippophae rhamnoides L.) does not find industrial use, despite the macro- and micro-elements and other biologically active substances contained in it, in particular – flavonoids. The composition of the meal determines its high biological value and the possibility of obtaining a pharmaceutical phytocomposition of anti-inflammatory action, which is important and timely in the current COVID-19 situation. Along with this, 80% of the world's population consider herbal medicines as an alternative to synthetic drugs, thanks to the well-known list of their properties. However, only a small part of polyphenols is absorbed in the small intestine, and the large part reaches the colon area without being absorbed. Therefore, an effective system of their delivery is required to achieve a therapeutic effect. To solve the tasks set in the work, a method of micronization of the purified flavonoid fraction of sea buckthorn meal has been developed. A rational mode of ultrasonic micronization has been determined: processing for 10 minutes at a power of 50 watts, during which the smallest particle size has been obtained – 1400 nm or less. The micronized sample is a homogeneous fine powder of brown-yellow color, neutral taste, odorless and foreign impurities, with a base substance content of 96 %, a moisture content of about 5 %, ash content of 0,04 %, toxic elements and extraneous microflora have not been detected, which indicates not only the high quality of the sample obtained, but also the manifested antibacterial effects of phenolic substances and ultrasonic treatment. Analysis of the micronization degree and the effectiveness of biological action has been confirmed by the example of antioxidant activity and phlebotropic action, indirectly proving P-vitamin activity. The micronization method provides a 4,5-fold reduction in particle size, an increase in prooxidant activity on the model of reduction of sulfhydryl groups of glutathione with a constant chemical composition of the complex.

A method has been developed for obtaining afood dispersion, where collagen-containing and mineral additives obtained from fish scales are used as a thickener-stabilizer. The process of obtaining them consists in processing fish scales in a mixer with the addition of dry table salt, baking soda and crushed ice, followed by rinsing with water. The washed scales are kept in an aqueous solution with the addition of a mixture of table salt, citrus peel and baking soda, followed by rinsing with water. The cleaned scales are air-dried, crushed and separated to obtain a fish collagen-containing additive having a fibrous structure and a mineral (powder) additive based on calcium hydroxyapatite. The basis of food dispersions was raw materials of animal (pork and minced chicken) and vegetable (zucchini caviar, white beans) origin. The basis of the food dispersion was mixed with a fish collagen supplement (0.5-10 %) and a mineral supplement (0.3-1 %), homogenized (vegetable raw materials) during heat treatment and cooled or kept in a refrigerator (animal raw materials) for 90 minutes, formed (meatballs) and heat-treated (180 0C for 20 minutes) in a combi steamer and cooled. The mass loss of raw materials during baking meatballs from minced poultry (37.51 % - control), depending on the content of the collagen additive (0.5-10 % of the total mass of raw materials), decreased and amounted to 35.54-28.22 % and accordingly, meatballs from minced pork (29.98 % - control) decreased and amounted to 24.67-20.04 %. Similarly, the mass loss of squash caviar (8 % - control) decreased to 2 %, and the loss of white bean paste-puree (13.3 % - control) decreased to 0.7 %.

The stress state of the links of the basic crank-rocker mechanism, due to the loads acting during the movement has been studied. The initial data for the analysis are the loads found earlier as a result of the mechanism dynamic analysis by uniform crank rotation. The finite element solution of the problem of finding stresses in the mechanism links is carried out using a 10-node tetrahedral element. The reliability of the numerical results is substantiated by comparing the solutions for meshes with initial and increased density. Calculations of the moving mechanism was performed for three variants of external loads: 1) taking into account only inertia forces; 2) taking into account the inertia and gravity forces; 3) taking into account the forces of inertia, gravity, as well as friction in kinematic pairs. The distributions of equivalent stresses in each of the mechanism links were obtained. The nature of the stresses change in the links during the cycle of the mechanism movement was studied, while the highest stress state level was noted near the bottom dead center (BDC) position i.e. 0.5 turn of the crank from the starting position. It has been found, that with simultaneous consideration of the inertia and gravity forces, the gravity forces exert the predominant influence on the links stress state for a given speed of the crank rotation. It has been shown, that taking into account friction in kinematic pairs does not fundamentally change the results of stress calculation, excluding the local region of the mechanism positions near the BDC. Quantitative data of the links stress state are the basis for their strength estimating. The obtained dependences of stresses on the position of the mechanism indicate their cyclic nature. The obtained dependences of stresses on the mechanism position indicate their cyclic nature. This circumstance means the need to exclude stress concentrators in the links structure in order to reduce the danger of fatigue failure.

The object of the study is an intermediate frequency and voltage converter, which is required to obtain electricity of the necessary parameters to power the ship's consumers. The goal is to improve the power supply system from the shore by installing a modern semiconductor converter to adapt the parameters of the power grid.

Currently, there is a problem of adapting the parameters of the ship's electrical network of foreign-made vessels to the standards of the domestic power supply system when powered from shore. The ship uses an engine-generator conversion system, which has a number of significant drawbacks. The paper considered the possibility of its replacement using a static frequency and voltage converter, which has a number of advantages over the existing scheme of power supply of the vessel from the shore.

In the process of work, the algorithm of power supply to consumers from both ship-based power sources and coastal networks has been investigated, frequency and voltage conversion schemes of the original converter and the one proposed in return have been analyzed, the designs of the converters have also been considered, advantages and disadvantages have been identified.

As a result of the study, the importance of observing network standards when powering ship consumers is emphasized, a modern converter of network parameters based on a static frequency and voltage converter has been proposed, a circuit for connecting the converter to the ship's electrical distribution system has been developed, economic and environmental justifications of the project have been presented.

As a result of the conducted research, a conclusion has been drawn that a static frequency and voltage converter can be used to convert electricity parameters, such as voltage and frequency, to power consumers requiring other values, as well as an intermediate point in the process of supplying electricity to a vessel from shore.

There is currently an increase in container traffic, which has led to an increase in the design and construction of new types of container ships, which are being developed not only to increase their main dimensions and container capacity, but also to provide better seaworthiness at the same time. Increasing the size of container ships takes into an account the requirements for accommodating a whole number of containers by length, widths and depth of the holds. For the five months of 2021, container ships with a total capacity of 2,2 million TEUs (twenty-foot equivalent, a unit of measurement for container capacity) have been ordered. This is 12 times more than for the same period in 2020 and 60 % higher than the previous record set at the beginning of 2005. The vast majority of the tonnage ordered in 2021 will be done in 2023. It is estimated to be around 1,5 million TEUs, and 2023 will be the record year for delivery of container ships. The paper analyzes 112 container ships built between 1979 and 2021, which were divided into three groups. The calculations show that the length to width ratio is greater for ships built between 2000 and 2011 than for "old" container ships, however, for container ships built between 2011 and 2021 the ratio is practically equal for "old" ships. The width to draft ratio of ships built in 2011–2021 is higher than that of container ships built in 2000–2010 and ships built in the 1980s. Container ships built between 2011 and 2021 have a shorter length to height ratio than "older" ships and container ships built between 2000 and 2010. The ratio of side height to draft for container ships built in 2011–2021 is greater than that for container ships built in the 1980s and for container ships built in 2000-2010. The length to draft ratio of container ships built in 2011–2021 is higher than that of container ships built in the 1980s and of container ships built in 2000-2010. An increase in the main dimensions of container ships has a favourable effect on all seaworthiness, but sea straits, canals with certain lock sizes and ports with limited depths in the fairways and at berths, do not allow a further increase in the main dimensions of the ships.

The paper presents the study of optical reflection spectra of rare-earth element oxide complexes (Tm₂O₃/Bi₂O₃, Tm₂O₃/Yb₂O₃, Tm₂O₃, Bi₂O₃, Yb₂O₃) . It is shown that the presence of ytterbium oxide in the Tm₂O₃/Yb₂O₃ mixture leads to a decrease in the reflection coefficient of tulium oxide in the ultraviolet region of the spectral range. In the presence of bismuth oxide in the Tm₂O₃/ Bi₂O₃ mixture the reflection maximum in the 350 nm range decreases 1.5 times. In the visible region of radiation in complexes with Tm₂O₃ at wavelengths of 462 and 475 and 490 nm there are minima of reflection coefficient equal to 85-90%. These minima correspond to transitions from the vibrational levels of the ground state ³H₆ → ¹G₄. This indicates that the Tm₂O₃/ Bi₂O₃ complex in the presence of Tm₂O₃ allows the reflection coefficients to increase in the visible region. The processes of electron excitation energy transfer have been investigated, as a result of which the effects of photoluminescence can be observed. The study also included the possible ways of energy transfer between the interacting centers, taking into account the upconversion luminescence of ytterbium oxide in the red region of the spectrum. It has been found that ytterbium or bismuth acts as a donor of energy transfer in paired complexes. X-ray structural analysis of bismuth oxide has been investigated, from which it follows that the synthesized phase of bismuth oxide Bi₂O₃ corresponds to monoclinic symmetry. Further studies will be related to the establishment of mechanisms of photoluminescence formation in the presented complexes and determination of the dynamics of the duration of excited states existence on the basis of spectral-kinetic studies. The study of photoluminescence processes is a major practical task.