Astrakhan State Technical University

Improving the safety of nuclear power plants with water-water (VVER) reactors requires the development of passive heat removal systems (PHRSs), especially for complete blackout conditions. An important aspect of the research is the simulation of PHRS operation at different values of a decay heat flux. Integration of absorption refrigerators (ARs) into the PHRS is promising for increasing the efficiency of heat removal. To simulate the PHRS operating in integration with ARs and to assess the increase in the energy efficiency and safety of the VVER-1000 reactor in emergency conditions. The object of study is the PHRS: the number of its channels (two 8 MW each) is selected based on the single failure criterion for assessing the system performance in the conditions of partial degradation. The mathematical simulation of the PHRS under severe conditions including the failure of active safety systems, which corresponds to an accident with the loss of most energy sources, the equations of core heat balance (core), used natural circulation of the coolant and decay heat. Initial conditions for calculations included the coolant temperature of 60–200 °C and pressure of 6.0 MPa. The basic PHRS configuration (2×8 MW) fails to provide sufficient heat removal at a decay heat of more than 50 MW: in the first 2 h, a shortage of cooling to 40 MW is observed due to the inertia of starting natural circulation and a limited heat exchange area of 800 m2, which leads to an increase in the fuel temperature to 900 °C in 1.5 h. Insufficient PHRS power was confirmed. Additional safety systems are required for VVER reactors, especially under blackout. The simulation of AR operation in the PHRS and the impact of ARs on the system performance, accident development time, and core heating dynamics will be presented in the publication “Simulation of an absorption refrigerator operated in the passive heat removal system of a nuclear reactor. Part 2”.

New diorganotin(IV) complexes R2Sn(Ln) 1-5 (where R = Et, t-Bu, Ph) with O,N,S-donor tridentate Schiff bases containing chlorine or trifluoromethyl groups were synthesized in 49-67% yields. Compounds 1-5 were characterized by 1H, 13C NMR, IR spectroscopy, and elemental analysis. The molecular structures of 2, 3, and 5in the crystalline state were determined by single-crystal X-ray diffraction. The organotin complexes are mononuclear and five-coordinate, with ligands adopting a dianionic form. Electrochemical studies revealed that the electrooxidation process is irreversible while the electrochemical reduction generates relatively stable monoanionic complexes. Complex 3, along with previously reported related phenyl-or ethyl-substituted tin compounds, exhibits luminescence in chloroform. The radical scavenging activity of the complexes was evaluated in reactions with ABTS radical cation or superoxide radical anion in NBT assay. The highest neutralizing properties were observed for complexes with ethyl substituents at tin atom; their IC50 values ranged from 6 to 35 mu M. In the oxidative DNA damage assays, most compounds exhibited a promoting effect suggesting their potential role in DNA cleavage under oxidative stress. However, in the lipid peroxidation model reaction in vitro, an antioxidant effect was observed for most compounds, particularly for hydrophobic tert-butyl-containing complexes 2 and 4.

Wastewater irrigation represents a promising strategy for addressing water scarcity and increasing food demand in arid and semi-arid regions. Although, wastewater is enriched with plant nutrients, its indiscriminate use may deteriorate soil and plant health by contributing to salinity buildup and heavy metal accumulation. Thereforem this study aimed to evaluates the effects of wastewater irrigation, applied alone and in combination with canal water, on soil quality, maize growth, nutrient uptake and heavy metal accumulation. A pot experiment was conducted using a completely randomized design (CRD) with six treatments and four replicates: T1, 100

Industrial facilities for the extraction and processing of oil and gas with a high sulfur content are a source of polluted highly concentrated hydrogen sulfide process waters. Industrial effluents at the Astrakhan gas condensate field are highly aggressive due to its features and undergo multi-stage purification. In view of the trends in resource conservation and environmental friendliness dictated by the complex environmental situation in the world, it is necessary to analyze in detail the existing wastewater treatment technologies for compliance with the principles of green chemistry and identify specific proposals. The article presents ways to improve the technological processes for purifying hydrogen sulfide-containing wastewater from the high-pressure reservoir gas separation plant of the Astrakhan Gas Processing Plant, which implements a combined method for purifying industrial wastewater and reservoir water from sulfides, carbonates and hydrogen sulfide. Its disadvantages are the unsatisfactory quality of water purification, the use of harsh reagents, multi-stage treatment, insufficient environmental friendliness and the preservation of risks to the environment. Advanced oxidation processes are a promising technology for wastewater treatment. When treating sulfide-containing wastewater, the Fenton reaction allows you to break down toxic sulfides to non-toxic compounds, remove hydrogen sulfide, and convert sulfides into sulfates, which are easier to remove from the water. Fenton's reaction reveals environmental and resource-saving benefits: high cleaning efficiency, carrying out the process at room temperature, and relative ease of implementation. A technological scheme is proposed for the treatment of highly concentrated sulfide-containing waters and local wastewater treatment with the transfer of hydrogen sulfide to a state of non-toxic, easily transported commercial sulfur. The requirements for the quality of effluents for the Fenton reaction are substantiated, the key factors determining the process are identified, and the technological scheme is adjusted. When making the proposed changes, such effects as greening production, shortening the length of the technological chain and reducing energy costs can be achieved by using the mild conditions of the Fenton process compared to steam.

This paper presents a multilingual voice control system for autonomous agricultural machinery, addressing the need for intuitive human–machine interfaces in precision farming. The proposed architecture integrates audio capture with a configurable speech recognition module based on Faster Whisper, which transcribes commands and optionally translates from one language to another. Recognized text is processed by a hybrid natural language understanding pipeline combining intent-and-slot-filling models (BERT/T5), and a local large language model (Qwen) for commands of varying complexity. Experimental evaluation shows that medium-sized Whisper models maintain 85–90