The ongoing climate changes heighten the interest in studying the patterns of carbon-containing gas exchange between the atmosphere and the underlying surface at various scale levels. Using two photoautotrophic species, Fucus vesiculosus and Honckenya peploides, which differ markedly in taxonomic position, morpho-functional organization, and habitat conditions, CO₂ gas exchange parameters have been examined in the coastal zone of Zelenetskaya Bay in the Barents Sea. The macroalga inhabits the littoral zone and photosynthesizes across the entire surface of its thallus, whereas the vascular plant occurs in the supralittoral zone and absorbs atmospheric CO₂ via the stomatal apparatus. The study was conducted using the chamber method in two configurations: transparent chambers were used to measure net ecosystem exchange (NEE), while dark chambers were used to measure ecosystem respiration (R_eco). Gross primary production (GEE) was calculated indirectly. The mean daily flux values (mg C m⁻² h⁻¹) differed between H. peploides and F. vesiculosus. NEE was −44.84 and −20.34, and R_eco was 19.59 and 33.05. No significant differences were observed in GEE. The amplitude of the NEE, Reco, and GEE oscillations of the photoautotrophs during the day was significant and reflected diurnal changes in environmental conditions and the physiological reactions of the organisms themselves. Relationships between CO₂ gas exchange parameters and environmental factors were identified. The primary factors influencing carbon dioxide fluxes were light intensity and temperature, while the tidal cycle additionally affected the gas exchange parameters of the macroalga.

This paper presents the results of a comprehensive assessment of the ecological and hydrochemical status and algal community of a small urban water body – an unnamed pond located in Pobedy Park (Kaliningrad) – conducted from April 2024 to March 2025. Based on the monthly monitoring across three sampling stations, the study identifies the spatio-temporal dynamics of key hydrochemical parameters, including dissolved oxygen, nutrients (ammonium nitrogen, nitrites, phosphates, total iron) and permanganate index. In order to provide a robust biological characterisation, the phytoplankton composition, abundance, and biomass have been analysed using standard hydrobiological protocols. The findings establish that the water body exhibits chronically high ammonium nitrogen levels, exceeding fisheries maximum allowable concentrations throughout the entire annual cycle, alongside critical dissolved oxygen deficit during the spring and summer months. A statistically significant correlation has been identified between precipitation intensity and the level of organic pollution. Furthermore, the total iron concentrations are of mixed origin, resulting from the combined influence of natural groundwater and runoff from urbanised areas. According to hydrochemical indicators, the pond can be classified as eutrophic, β-mesosaprobic. Algological analysis revealed the dominance of green algae, diatoms and cyanobacteria; peak phytoplankton biomass values indicate the ecosystem's eutrophic status. The morphometric characteristics of the pond, coupled with local point sources of pollution, drive pronounced spatial heterogeneity in environmental quality; specifically, the northern sector of the pond serves as a primary accumulation zone for pollutants due to the influx of stormwater runoff.

The relevance of the study is determined by the need to preserve the structure and quality of fish mince systems during their inter-operational transportation by rotary lobe pumps in food production lines. Existing manufacturers' recommendations on limiting rotor speed are primarily applicable to Newtonian fluids and do not account for the complex rheological behaviour of fish minces, which is characterized by yield stress, pseudoplasticity, and thixotropic destruction of the fibrous structure under shear deformation. The aim of this work is to improve the method for determining the maximum permissible rotor speed of rotary lobe pumps when pumping pollock mince with various fillers (millet, buckwheat, oat flakes, rye flour). Based on a rheological model describing shear stress as a sum of instantaneous-elastic deformation, plastic shear, and viscoelastic flow components, an analytical dependence of effective dynamic viscosity on rotor speed has been derived. For JRZL-series pumps, a generalized formula relating permissible speed to pump working volume and dimensionless viscosity of the pumped medium has been obtained, with the exponent β = 0.181 remaining constant across the entire pump line. An algorithm for solving the nonlinear equation to calculate limiting pump operating modes has been developed. It has been found that for the RZL-120 pump, transitioning from mince without additives to mince with rye flour reduces the permissible rotor speed from 232 to 68.7 rpm. The proposed methodology enables a scientific election of pump type and operating mode, ensuring product quality preservation and optimization of energy efficiency indicators in food processing technologies.

The study presents a comprehensive assessment of the environmental safety of plant-based milk alternatives available on the Russian market. The study included both ready-to-drink commercial beverages from popular brands and laboratoryprepared samples from cereal raw materials. The primary objective has been determination of the levels of toxic and conditionally toxic heavy metals- lead, cadmium, zinc, and copper – and subsequent assessment of the potential non-carcinogenic health risk to adults and children with regular consumption of these products. Laboratory analysis has been performed using atomic absorption spectrometry. The resulting quantitative data have been compared with the established hygienic standards (MPCs). To convert chemical concentrations to health impact assessment, an approved method for calculating exposure doses and hazard quotients (HQs) has been used. The analysis results showed that none of the samples, whether industrial or laboratory, exceeded the MPCs for all four metals. Concentrations varied within safe limits, ranging from 4.8 % to 36.7 % of the corresponding MACs. The key result of the integrated assessment is the calculation of the hazard quotient (HQ). Its values for each metal, as well as the overall risk indicators for all beverage types for adults and children, were significantly less than one (less than 0.01). This clearly indicates no risk of developing non-carcinogenic health effects with long-term consumption. Thus, the study demonstrates that the plant-based milk analogues examined possess a high level of environmental safety in terms of heavy metal content. It has been found that the decisive safety factor is the quality of the original agricultural raw materials, not the type of processing (industrial or laboratory prepared).

High content of free moisture and active enzymes in fresh fruits and vegetables determines their perishable nature and leads to significant losses during storage and transportation, reaching 56 thousand tons annually in the Kaliningrad region. Fruits with visual defects constitute a particular portion of these losses, as they are discarded despite retaining high biological value. This underscores the relevance of developing efficient technologies for their processing. This paper presents research on improving the technology for producing the functional food additive "VITUMIN" from lowgrade fruits by intensifying the bioconversion of raw materials through two-stage enzymolysis. The composition of the carbohydrase enzyme complex has been substantiated based on the polysaccharide profile of the source fruits (apples, bananas, oranges). The first stage involves treatment with cellulase and pectinase to disrupt cell walls and release biologically active substances (BAS); the second stage utilizes β-glucanase, Glucavamorin, and Alphalad BT to hydrolyze the released polysaccharides. Using mathematical modeling, we determined the optimal values for the first-stage factors: temperature 49°C, pH 3.8, and duration of 2 hours. The effectiveness of the developed scheme has been experimentally confirmed: the liquid fraction yield increased by 62.3%, the dry matter content by 15.7%, and the yield of the target additive increased by 7.9% compared to single-stage processing. IR spectroscopy data confirmed the profound degradation of the cellulose-pectin complex. The resulting additive is characterized by a high content of vitamins C (66.5 mg/100 g) and P (122.5 mg/100 g), meets the microbiological safety requirements of TR CU 021/2011, and is recommended for use in enriching traditional, functional, and specialized food products.

The article presents the results of a microbiological study devoted to assessing the stability of a new pasteurized fish paste enriched with functional components. The following functional ingredients have been selected: food grade inulin, which has been introduced as a powder, and dried crushed Fucus vesiculosus. The microbiological parameters of the components of the paste formulation that pose an increased risk have been studied: frozen cod and bubbly fucus. During the experiment, which lasted 75 days, comparative monitoring of three samples of the pasteurized product was carried out: control sample – pasteurized fish paste without functional components, stored in optimal conditions at a temperature of 4 ± 2 °C; prototype 1 – pasteurized fish paste with functional components, stored in optimal conditions at a temperature of 4 ± 2 °C; prototype 2 – pasteurized fish paste with functional components, stored in extreme conditions at a temperature of 22 ± 2 °C. The stability of fish pastes during storage has been determined by the complex influence of two factors: the formulation (presence / absence of functional components) and compliance with the temperature regime. It has been found that the components of the fish paste formulation, as well as the finished samples, with and without functional components, stored in optimal conditions throughout the experiment corresponded to all indicators (TAMC, coliforms, molds, S. aureus, V. parahaemolyticus, B. cereus, sulfite-reducing clostridia) EAEU Technical Regulation 040/2016 "On the safety of fish and fish products". For comparison, a microbiological analysis of an analog product purchased at a supermarket with a similar formulation at the end of the shelf life has been carried out.

The paper is devoted to solving the problem of hydrodynamic optimization of a passenger catamaran designed to organize a ferry crossing in the Curonian Lagoon in order to develop domestic tourism. The main attention is paid to the comparative analysis of asymmetric body configurations known as "IF" (with a flat inner wall) and "OF" (with a flat outer wall), which potentially provide a gain in resistance compared to traditional symmetrical contours. The theoretical basis of the project was the analysis of literature sources, which revealed contradictory data on the superiority of one or another asymmetric scheme, which necessitated an experimental study. The proven Schwetz series (M5-CH) was chosen as the base, providing good seaworthiness. At the next stage, model tests were conducted in an experimental pool. The scale model under test (1:16) made it possible to vary the relative transverse clearance (s/L = 0.20; 0.30; 0.35). The tests of two configurations ("IF" and "OF") were performed in the range of Froude numbers corresponding to speeds of 12–20 knots for a full-scale vessel. The key measured parameters were the towing resistance and wave pattern, and the main evaluation criterion was the interference coefficient of residual resistance. The test results showed that the "OF" configuration with the maximum relative lateral clearance (s/L = 0.35) is optimal for the target high-speed mode (17–20 knots). This scheme demonstrated the lowest residual resistance and the most favorable interference of wave systems, which resulted in the practical absence of noticeable wave formation in the internal space between the housings. This indicates a minimal mutual negative impact of the buildings. Thus, an asymmetric catamaran with "OF" type hulls and maximum transverse clearance is recommended for further design of a passenger ferry for the Curonian Lagoon.

It is known that water-fuel emulsions used in diesel engines have a number of advantages over traditional diesel fuels, which significantly affects the efficiency and environmental performance of the engines. The use of water-fuel emulsions can be associated with several problems related to their stability, such as phase separation, coalescence, and sedimentation, as well as the quality of the components and others. These issues encourage researchers to thoroughly study the properties of water-fuel emulsions and improve methods for their production. This paper presents the results of a study of the stability of water-fuel emulsions using photon correlation spectroscopy and the kinetics of changes in T₂ NMR relaxation times during the sedimentation of emulsion water droplets using the example of a Euro C diesel fuel + water system. It is shown that over time, a transition from a unimodal distribution of water droplet hydrodynamic radii to a bimodal distribution can be observed. This is explained by a sharp increase in droplet aggregation and the weakening of this process by the emulsifier, the concentration of which decreases in the beam scattering region. NMR T₂ relaxation times measured using Niumag NMR Data Analysis Software V1.1 (Pore Size Distribution) made it possible to determine the size distribution of water droplets in the emulsion using an alternative method. A longer emulsion separation process was found in samples with a longer emulsification time. An emulsion obtained without an emulsifier is very unstable due to strong coalescence and quickly separates. Prolonged whisking is essential for obtaining a stable, finely dispersed emulsion. The optimal emulsifier amount is no more than 1%. The results obtained in this study can be useful for dispersion analysis of any organic emulsions containing microscopic droplets of immiscible liquid.