International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The long-term reliability of reinforced concrete structures is strongly influenced by electrochemical deterioration processes affecting embedded steel reinforcement. In addition to conventional environmental actions, stray electrical currents may disturb the passive state of reinforcing steel and contribute to the initiation or acceleration of corrosion, particularly when combined with chloride-contaminated environments. This study proposes a multi-parameter framework for assessing the electrochemical reliability of reinforced concrete structures subjected to combined electrical and environmental actions. The assessment is based on three principal electrochemical indicators: reinforcement corrosion potential, electrical resistivity of concrete and corrosion current density. Five representative exposure scenarios are considered, ranging from a reference condition without significant electrical influence to combined exposure involving increased moisture, chlorides and simulated stray currents. The selected parameters are integrated into a dimensionless Electrochemical Reliability Index (ERI), developed to enable comparative classification of structural condition and deterioration risk. The proposed methodology combines normalised electrochemical indicators with a weighted deterioration model and sensitivity analysis. For the baseline weighting system, the calculated ERI values decrease from 1.000 for the reference K0 condition to 0.846 for E1, 0.651 for E2, 0.374 for E3 and 0.000 for the highly aggressive E4 scenario. The most pronounced reliability reduction occurs between moderate electrical influence and simulated stray-current exposure. Sensitivity analysis confirms that the ranking K0 > E1 > E2 > E3 > E4 remains unchanged under three weighting systems. The proposed framework is intended as a comparative engineering assessment tool rather than a substitute for detailed structural inspection or standardised corrosion diagnosis. Its principal contribution lies in integrating complementary electrochemical parameters into a unified reliability-oriented indicator that may support condition assessment, maintenance prioritisation and durability management of reinforced concrete structures exposed to complex electrical and chloride environments.

Activated carbon was prepared from waste polystyrene through acid treatment and pyrolysis to obtain a porous adsorbent with controlled structural features. Nitrogen adsorption reveals a type IV isotherm with H4 hysteresis and a high specific surface area of 1382 m²/g, indicating combined micro- and mesoporosity. SEM imaging shows irregular carbon agglomerates with a highly textured surface, while elemental and FTIR analyses confirm an aromatic carbon matrix with limited heteroatom functionality. These structural and chemical features demonstrate that the synthesized carbon material is well-developed and suitable for further application-oriented studies, including detailed adsorption performance evaluation.

Neutron polarizing super-mirrors are aperiodic multilayer structures made of alternating magnetic CoFe and non-magnetic TiZr layers deposited on glass or silicon substrates using the magnetron sputtering method. The polarizing ability of such super-mirrors and the efficiency of their use depend on the fine ratio of the thickness of the layers and the relative metal content in the layers [1, 2]. X-ray fluorescence analysis (XRF) is highly sensitive, but it has a rather large relative error, usually not less than 5%. An original X-ray spectrometer with a radioisotope source based on 109Cd was used to determine the content of Fe, Co, Ti, and Zr in super-mirror samples with sufficient accuracy to control their manufacturing technology. The XRF analysis was based on the direct external standard method taking into account absorption corrections. As a result, the relative metal content in the super-mirror layers was determined with a relative error of less than 1%.

Neutron polarizing super-mirrors are aperiodic multilayer structures made of alternating magnetic CoFe and non-magnetic TiZr layers deposited on glass or silicon substrates using the magnetron sputtering method. The polarizing ability of such super-mirrors and the efficiency of their use depend on the fine ratio of the thickness of the layers and the relative metal content in the layers [1, 2]. X-ray fluorescence analysis (XRF) is highly sensitive, but it has a rather large relative error, usually not less than 5%. An original X-ray spectrometer with a radioisotope source based on 109Cd was used to determine the content of Fe, Co, Ti, and Zr in super-mirror samples with sufficient accuracy to control their manufacturing technology. The XRF analysis was based on the direct external standard method taking into account absorption corrections. As a result, the relative metal content in the super-mirror layers was determined with a relative error of less than 1%.

As additive manufacturing (AM) technologies continue to gain traction across various industries, researchers have increasingly focused on optimizing the mechanical performance of polymer parts produced through material extrusion (MEX). Among the manufacturing parameters involved, infill pattern and density stand out as key factors that directly determine the mechanical behavior and energy absorption capacity of printed components. This study examines how different infill density gradients influence energy absorption, focusing specifically on samples built from polylactic acid (PLA) filament using a Triply Periodic Minimal Surface (TPMS-D) diamond pattern. TPMS-based infill patterns were selected for this study due to their potential to offer superior mechanical properties and energy absorption capacity compared to conventional two-dimensional infill patterns. The samples were subjected to quasi-static compression tests, from which stress-strain curves were obtained and energy absorption properties were calculated. The findings of this study are expected to inform the optimization of infill pattern and density parameters for energy-absorption applications, while also offering practical guidance for designing lightweight structures capable of withstanding high-energy impacts.

This study evaluates the applicability of Powder Forging for producing hypercompositional structures from heat-resistant powders based on Inconel 625, ZhS6U, and CoCrAlY alloys. One-step forging and triple forging at 1150 °C were examined to determine their influence on densification, prior particle boundary elimination, microstructural evolution, and high-temperature mechanical behaviour. Triple forging markedly improved interparticle bonding, reduced structural defects, and enabled the formation of dense composite architectures with statistically distributed constituents. The Inconel 625-ZhS6U and Inconel 625-CoCrAlY systems demonstrated high yield strength over a broad temperature range and exhibited anomalous strengthening at elevated temperatures, attributed to dynamic strain aging and phase redistribution. The results confirm that Powder Forging is a promising thermomechanical route for designing advanced heat-resistant powder composites for aerospace hot-section applications.

The selection of an appropriate structural and construction system significantly influences material consumption, energy demand, construction duration and overall project efficiency. This study presents an integrated parametric methodology for comparing prefabricated and conventional cast-in-situ reinforced concrete systems under equivalent functional and structural requirements. A representative five-storey building with a gross floor area of approximately 5,000 m² is analysed using two construction scenarios: CIS (conventional cast-in-situ reinforced concrete) and PRE (prefabricated reinforced concrete). The assessment incorporates concrete and reinforcement consumption, material losses, structural construction duration, embodied energy of principal materials, additional production energy, transportation and site energy. The analysed performance dimensions are integrated into a dimensionless Construction Efficiency Index (CEI), while sensitivity analysis evaluates the influence of decision priorities. At a reference factory-to-site distance of 50 km, the parametric scenario indicates a reduction of approximately 7.8% in total structural-material input, 25% in structural construction duration and 6.2% in total energy demand for PRE relative to CIS. The baseline CEI increases from 1.000 for CIS to 1.153 for PRE. The study additionally introduces a project-specific break-even transportation-distance model. Under the adopted assumptions, the energy advantage of prefabrication disappears at approximately 185 km, whereas the integrated CEI advantage persists to a substantially larger theoretical distance because material and time benefits remain. The proposed framework demonstrates that prefabrication should not be evaluated through a single indicator. Its relative advantage depends on the combined effects of materials, energy, time and logistics. The methodology is intended as an early-stage engineering decision-support approach and requires project-specific inventory data for application to real construction projects.

Composite materials with potential application in medical textiles were developed by modifying cotton fabric with chitosan containing diclofenac. The influence of the concentration of citric acid as a crosslinking agent on the properties of the materials was studied. The resulting composite materials were characterized by gravimetric analysis, optical microscopy, contact angle measurement and thermogravimetric analysis. The antimicrobial activity of the cotton samples was evaluated against Gram-positive and Gram-negative model bacterial strains. A synergistic antimicrobial effect of chitosan and diclofenac and a uniform release of diclofenac in vitro under physiological conditions were established.

In this study, we present the key results of computer modeling and experimental series of a combined technological process that integrates hydro-vacuum atomization and hydrogenation of metallic melts. The simulations considered several representative cases in which lead, aluminum, magnesium, Armco iron, and magnesium–aluminum alloys were used as initial materials. A comparative analysis of the obtained data revealed that, during hydro-vacuum atomization, the cooling, solidification, and hydrogenation kinetics of atomized droplets are strongly governed by the specific thermodynamic characteristics of the metals, such as the solidification interval, latent heat of fusion/solidification, and specific heat capacity. It was established that the relationship between the melt overheating temperature and the width of its solidification interval constitutes a key controlling factor in the combined processes of atomization and hydrogenation. This factor is critical because it determines both the duration and the nature of the residence of atomized metallic droplets in the transitional liquid–crystalline state, thereby defining the temporal window and the depth of highly effective physico-technological influences that promote hydrogen uptake. These influences arise during the entrainment and breakup of the melt jet in the water stream and include hydromechanical activation, structural metastabilization, and interstitial hydrogen incorporation released from collapsing cavitation cavities in water due to the thermobaric energy generated during their directed cumulative implosion.

The basic prerequisite for trouble-free assembly of moving structures is that the assembled structure has as many degrees of freedom as its function requires. In practice, we often encounter cases of statically overdetermined pairs. Designers often use them to increase the rigidity of products. This article describes a way to mitigate the consequences of problematic assembly in sliding pairs, which are often statically overdetermined. The article also addresses an important problem in assembly, which is repeated assembly accuracy, especially when designing assembly lines and automated and robotic systems.

To reduce the sintering temperature in the microstructural design of α-Al2O3-based ceramics, a mixture of basalt glass and yttria-stabilized zirconia (YSZ) was used. The effect of isothermal holding time during liquid-phase sintering of a composite containing 85 wt.% α-Al2O3 and 15 wt.% (basalt glass + YSZ) on its mechanical properties was investigated. The samples were sintered at temperatures of 1450 and 1500 °C for 2–6 hours. It was established that sintering occurs in the presence of a liquid phase that persists throughout the entire holding period, and the densification of the material is determined by the rearrangement and Ostwald ripening processes of Al2O3 grains. The maximum hardness reached 7.73 GPa, while the fracture toughness reached 7.95 MPa•m¹ᐟ². The effect of microstructural evolution on the hardness and fracture toughness of the composite was demonstrated.

Reinforcement corrosion remains a major cause of premature deterioration of reinforced concrete infrastructure, especially when chloride ingress and stray direct currents act simultaneously. This paper develops and computationally demonstrates an artificial intelligence-assisted framework for predicting a relative electrochemical deterioration score from seven measurable inputs: corrosion potential, concrete electrical resistivity, corrosion current density, chloride content, moisture, temperature and stray-current intensity. A reproducible synthetic parametric database of 1,200 scenarios was generated within physically plausible engineering ranges. Four supervised learning models—an artificial neural network, Random Forest, support vector regression and Gradient Boosting—were trained using a 75/25 stratified train-test split. Prediction accuracy was assessed by R², mean absolute error and root mean square error, while permutation importance was used to interpret the dominant predictors. The ensemble models achieved the strongest performance, and the importance analysis confirmed that corrosion current density, chloride content and electrical resistivity exerted the largest influence on the predicted condition. The results are a methodological demonstration rather than validation against laboratory or field measurements. The proposed workflow is intended to complement conventional electrochemical inspection, support maintenance prioritisation and provide a transparent basis for future calibration using monitored reinforced concrete structures.