Journal of Civil Protection

The structural memory of foam or the influence of foam generation on foam stability

Andrey N. Kamlyuk — 2026-08-28

Purpose. To justify the concept of foam structural memory coefficient and evaluate the influence of methods of its generation on the value of this parameter.

Methods. Theoretical and empirical analysis methods were applied during the research.

Findings. By generalizing the experimental results of low-expansion foam generation via various methods (whipping on a solid surface, blowing through wire mesh cells, barbotage, and injecting compressed air into a foaming agent solution by a compressor), a regularity has been revealed that links foam stability and its expansion ratio through the characteristic time of structural relaxation (foam structural memory). For the first time, foam structural memory is represented as the product of the wetting capacity index and the structural memory coefficient, which is inversely proportional to the Capillary number. A comparison was made of structural memory coefficients for various foam generation methods and their influence on enhancing foam stability.

Application field of research. The results of the analysis can be applied to the development of new foam-generating devices and the improvement of existing foam production methods.

Study of factors determining the resistance of surface fire protection of cotton-polyester fabrics to water treatments

Valentina V. Bogdanova — 2026-08-28

Purpose. Development of formulations for fire-retardant compounds and optimal conditions for their use in the production of cotton-polyester fabrics of varying density that retain fire resistance after water treatment.

Methods. Sol-gel method of synthesis from solutions; X-ray fluorescence spectroscopy, differential scanning calorimetry, transmission electron microscopy, IR spectroscopy; GOST-standardized test methods.

Findings. The methods have been developed for the preliminary activation and surface fire-retardant treatment of cotton-polyester fabrics of various compositions and densities using synthetic fire-retardant compositions. It has been established that the flame-retardant components become fixed primarily on the cotton component of the blend fabric; furthermore, the durability of the flame-retardant effect after washing depends on the presence of the complete set of components: the flame retardant, mediating agents, and agents that loosen the fabric structure. The resulting permanent flame-retardant effect in blended textile materials is primarily attributed to the chemisorption of reactive colloidal particles by the surface-active groups of the cellulose matrix.

Application field of research. Production of effective inorganic flame-retardant compositions and flame-resistant cotton-polyester blended textile materials resistant to water treatment.

Reduction of situational awareness (alertness) as a factor of professional errors under stress conditions

Veronika A. Metel'skaya — 2026-08-28

Purpose. Analysis of the impact of occupational stress and the resulting decline in situational awaerness (alertness) on the likelihood of professional errors among employees of wood-processing enterprises.

Methods. Comparative analysis, categorical analysis, structural-functional analysis of model representations, and analysis of cause-and-effect relationships.

Findings. A theoretical analysis was conducted of domestic and foreign studies regarding occupational stress, cognitive functions, and situational awareness under exposure to harmful occupational factors. The neurophysiological mechanisms underlying the decline in vigilance caused by local vibration and psycho-emotional strain were examined. Asymmetric vibration induces cerebral dysfunction and sensorineural deficits, manifesting as slowed sensorimotor reactions and reduced voluntary control over activity. The paradoxical effect of professional experience lies in the development of automatic behaviors that diminish the critical assessment of risks. Chronic fatigue and stress deplete the body's compensatory resources, thereby increasing the likelihood of errors, particularly in non-standard situations. Moreover, the cumulative effect of long-term vibration exposure exacerbates neurosensory impairments, laying the groundwork for a persistent decline in cognitive reserve that persists even during rest periods. A conceptual model of occupational error formation is proposed; this model encompasses neurophysiological, cognitive, and organizational-behavioral levels and accounts for the temporal dynamics of the progressive decline in vigilance throughout both the work shift and the entire professional career.

Application field of research. Development of methods to prevent occupational errors at woodworking enterprises based on managing stress factors and enhancing personnel's situational awareness.

Optimization of the geometric parameters of the flow path of a portable angle device for mounting hand-held fire nozzles using the finite element method

Artem A. Morozov — 2026-08-28

Purpose. To optimize the geometric parameters of the flow path of a portable angle device for attaching hand-held fire nozzles (hereinafter referred to as the angle device) ensuring minimal hydraulic losses and maximum efficiency of fire extinguishing agent delivery at stationary nozzle fixation.

Methods. The problem was solved using the finite element method in the Ansys Fluent software package. A geometric model of the flow path of the angle device with a fixed diameter of 50 mm was made. To ensure convergence of the solution, an adapted finite element mesh with explicit resolution of the near-wall area was used. Turbulent fluid flow was simulated using the SST turbulence model. A parametric analysis was performed for five variants of the first elbow length (100–300 mm), four variants of the second elbow length (50–200 mm), and four variants of the angle between elbows (20–50°). Verification of the results was carried out by comparing two-dimensional and three-dimensional axisymmetric calculations. Full-scale tests of the prototype were conducted during practical training sessions.

Findings. The optimal geometric parameters of the flow path of the angle device were determined: first elbow length – 250 mm, second elbow length – 50 mm, the angle between elbows – 20°. At a pressure of 709,3 kPa (7 atm) at the inlet section of the angle device, the following flow hydrodynamic characteristics are achieved: mass-average velocity – not less than 35 m/s, pressure – not less than 650,5 kPa (6,42 atm), turbulent kinetic energy – not more than 3,5 J/kg. It has been demonstrated that increasing the length of the second section to 200 mm results in a 90 % increase in the kinetic energy of turbulent fluctuations, while increasing the angle between the sections from 20° to 50° leads to a 50 % increase, with only a negligible rise in velocity (no more than 3 %). Field tests confirmed the device's functionality, its stability on a horizontal surface, and its effectiveness in reducing the physical strain on personnel.

Application field of research. The obtained results can be used by the Ministry of Emergency Situations of the Republic of Belarus when equipping firefighting units with devices for stationary fixation of hand-held fire nozzles. The developed angle device is recommended for use in firefighting under conditions of increased threat to personnel (risk of explosion, sudden structural collapse, intense thermal exposure), when extinguishing electrical installations, as well as in situations with insufficient manpower and resources. The presented numerical modeling methodology can be used for optimizing the flow paths of other types of firefighting equipment, including foam generators and water-foam nozzles.

Calculation of the performance of diamond cutting tools for cutting concrete, reinforced concrete and steel

Vitaliy E. Babich — 2026-08-28

Purpose. Prediction of performance indicators of diamond cuttings of wheels during dry cutting of materials used to eliminate the consequences of situations on the base of complex calculation methodology based on the provisions of the mechanics of contact action.

Methods. A functional-structural analysis of cutoff wheels for various materials, including the determination of dimensions and similarity, with a justification of dimensionless criteria that enable the generalization of cutting conditions of various materials.

Findings. This article presents the results of theoretical and experimental studies of the process of cutting structural materials by a diamond cutting wheel with an abrasive cutting device. Calculations have been carried out to determine the instantaneous performance, specific diamond consumption and cutoff wheels life when cutting various materials. It has been established that at dry cutting of 45 steel, the specific diamond consumption is at its maximum and the cutoff wheel life is at its minimum, rendering the process economically unviable.

Application field of research. Development of a versatile diamond cutting tool with enhanced performance for cutting concrete, reinforced concrete and steel. The results can be used when planning operations on cutting building structures and optimizing operating conditions of diamond tools, as well as during emergency response.

Metrological aspects of using rotameters in determining the minimum extinguishing concentration of gaseous fire extinguishing agents by the cup burner method

Ivan A. Bunto — 2026-08-28

Purpose. The increasing of the results reliability of measurements of the actual volumetric flow rate of various gaseous fire extinguishing agents (GFEA) when determining the minimum fire extinguishing concentration (MEC) using the «cup burner» method.

Methods. Experimental research, comparative analysis methods.

Findings. The metrological aspects of the use of rotameters when conducting tests to evaluate the MEC using the «cup burner» method are analyzed. Regulatory inaccuracies and metrological inconsistencies in current technical regulatory legal acts governing the conduct of tests on MEC definition have been identified and scientifically substantiated. It has been confirmed that the use of rotameters calibrated on air to determine the true value of GFEA consumption requires mandatory consideration of the physico-chemical properties of a particular GFEA, as well as environmental conditions during testing. The validity of two key assumptions when determining the MEC was experimentally substantiated and confirmed: the possibility of neglecting the temperature factor and the correspondence of the absolute pressure inside the rotameter to the current atmospheric pressure.

Application field of research. The obtained results can be directly used in certification testing of GFEA to determine the true flow rate value when determining the MEC. The obtained results can also be taken into account when updating existing and developing new interstate standards that establish GFEA requirements and test methods for an objective assessment of their fire extinguishing properties and verification of safety in accordance with international requirements.

Organizational basis of managing the fire emergency and rescue service of civil defense

Vitaliy A. Khrokolov — 2026-08-28

Purpose. Based on an analysis of the organizational foundations of managing the fire rescue service of the civil defense of the Republic of Belarus, to develop proposals for improving the existing structure of the system of management bodies of the fire rescue service of civil defense.

Methods. General scientific research methods: analysis and synthesis, comparison and generalization.

Findings. The essence and mechanism of action of the laws of military management are revealed, contradictions in the construction of the existing structure of the management system of the fire emergency rescue service of the civil defense of the Republic of Belarus are identified, and proposals for its improvement are presented.

Application field of research. The results of the study can be applied in the construction (refinement) of the organizational structure of the system of governing bodies of the fire emergency rescue service of civil defense, as well as in the educational process when training students receiving advanced higher education in the specialty 7-06-033-02 «Emergency Protection Management».

Fire hazard of stretch ceilings made of polyvinyl chloride film

Igor' S. Gusarov — 2026-08-28

Purpose. Investigation of fire hazard of stretch ceilings manufactured from polyvinyl chloride film (PVC film) using the flammability group determination method according to the GOST 30244-94.

Methods. Theoretical analysis, empirical data analysis, experimental method, comparative analysis, and systems analysis.

Findings. An empirical analysis of the fire hazard of stretch ceilings made of PVC film was carried out. It was established that the current certification system under the GOST 30244-94 «Construction materials. Test methods for combustibility» does not correspond to the actual operating conditions of PVC films and gives contradictory results: depending on the method of sample mounting, the same PVC film may be classified both combustibility group G1 (low-combustible materials) and combustibility group G4 (highly combustible materials). Moreover, neither test method simulates the real behavior of PVC film in a fire. It was revealed that the main hazardous factors are not so much the combustibility parameters as the formation and falling of burning melt droplets, sagging of the material, and its high sensitivity to thermal effects arising from emergency conditions in electrical networks. The examples of real fires in residential buildings provided in the article showed that ignitions occur primarily due to heating of the room air to a critical temperature (burning food on the stove, heat flow of combustion products of furniture and equipment) but not due to direct exposure to an open flame, what is not taken into account in certification. The conclusion was made regarding the need to develop new methods for assessing fire safety of PVC films and to supplement technical regulations with requirements that take into account the specific risks associated with the use of stretch ceilings.

Application field of research. The results of the work have practical significance in the field of certification systems of building materials, regulatory activities (in particular, while amending Technical Regulation 2025/013/BY), construction and interior design, as well as in the activities of emergency units and subunits.

Limit values of the jet speed of the foaming agent solution and air, required for generating air-mechanical foam obtained by various methods

Andrey N. Kamlyuk — 2026-08-28

Purpose. Theoretically and experimentally evaluate the minimum and maximum jet velocities of foaming agent solution or air necessary to generate low-multiplicity air-mechanical foam obtained by various methods.

Methods. Theoretical and empirical analysis methods were applied during the research.

Findings. As a result of the experiments, data were obtained on the velocity of the jet of the foaming agent solution during its movement from the outlet to the contact with a solid surface and a metal mesh, as well as a flooded jet of air exiting the hole into the foaming agent solution. It is shown that foaming is possible only within a narrow range of jet velocities: υ_min ≤ υ_jet ≤ υ_max. The numerical values of υ_min and υ_max depend on the surface tension of the solution and the dynamic viscosity, cell sizes of the metallic mesh, and densities of the solution and air. To form a compression foam, it is necessary to ensure that the air velocity reaches its critical value equal to the local speed of sound in the orifice, which depends on temperature. In this paper, it is proposed to distinguish between sparging and compression foam by the relative pressure β_c = 0,528.

Application field of research. The results of the research can be applied to develop new foam-generating devices and improve existing foam production methods.

Analytical justification of a protocol of assessing large language models for use in educational systems

Andrey V. Surikov — 2026-08-28

Purpose. To analyze known issues related to the quality of large language models (LLMs), architectural solutions aimed at improving the quality, and integrating models into electronic systems, including educational systems, and existing LLM assessment systems (hereinafter referred to as benchmarks) to justify the development of a multidimensional model assessment protocol for the Russian-language legal education segment.

Methods. The general methodology of the study included the use of theoretical research methods: analysis and synthesis of scientific and technical sources on LLM quality issues, integration technologies, and existing benchmarks.

Findings. LLM integration technologies into specialized applications were systematized. Four non-overlapping deficiencies in existing benchmarks were identified (lack of pedagogical assessment, Russian-language legal educational benchmarks, validation of direct context for terminology explanation, and multidimensional measurements of quality × response time × context length).

Application field of research. The obtained results can be applied to the development of LLM evaluation procedures in educational systems in the field of regulatory and legal activities of state fire safety authorities to justify reasonable selection of a model for local deployment under conditions of limited hardware and variable context volume.

The most important research results of the subprogram «Safety of human, society and state» of the state scientific research program «Digital and space technologies, safety of human, society, and state» for 2021-2025

Aleksey Yu. Lupey — 2026-08-28

The most important results of research work obtained under the subprogram «Safety of human, society and state» of the state program of scientific research «Digital and space technologies, safety of human, society and state» for 2021-2025 are presented. Their scientific novelty, economic and social significance are shown.