Resistance Coefficient Research Articles

Study of the influence of ultra-high molecular weight polyethylene and high-density polyethylene on the properties and structure of ethylene propylene diene monomer rubber

Objectives. The study set out to examine the impact of pre-mixed ultra-high molecular weight polyethylene (UHMWPE) and high-density polyethylene (HDPE) on a range of properties and structural characteristics of SKEPT-50 ethylene propylene diene monomer (EPDM) rubber.Methods. The production of rubber mixtures involved the pre-mixing of rubber with UHMWPE and HDPE in a Brabender PL 2200-3 plasti-corder chamber (Germany) at a temperature of 160°C, for a period of 6 min, and with a rotor speed of 60 rpm. The polyethylene constituents were incorporated into the rubber compound at concentrations of 5, 10, and 15 pts. wt. The subsequent introduction of the principal constituents of the rubber mixture was conducted in an SYM laboratory mill (China) for a period of 30 min at a temperature of no more than 100°C. The vulcanization of the samples was conducted in an Y1000D vacuum hydraulic press (China) at a temperature of 185°C for a period of 35 min. The investigation of vulcanization and physical and mechanical properties was conducted in accordance with the established protocols. The analysis of the rubber supramolecular structure was conducted using a JEOL JSM-6840 LV scanning electron microscope (Japan).Results. The results demonstrate that an increase in the proportion of HDPE and UHMWPE to 15 pts. wt leads to a notable enhancement in the hardness of the rubbers by 10 and 5 Shore A units, respectively. The frost resistance coefficient at −45°C demonstrates an increase with the incorporation of 10 pts. wt of HDPE to reach a value of 0.229, and a further increase with the incorporation of 15 pts. wt of UHMWPE to reach a value of 0.260. The degree of swelling of rubbers in a DOT-4 brake fluid environment is observed to decrease to 13% for rubbers with HDPE and 19% with UHMWPE. The degree of swelling of rubbers in the DOT-4 brake fluid environment is observed to decrease to 13% for rubbers with HDPE and 19% with UHMWPE. While an increase in the HDPE content results in a 5% increase in volumetric wear, an increase in the UHMWPE content is associated with a 45% decrease in volumetric wear. The introduction of UHMWPE was observed to result in the formation of inclusions of varying shapes and sizes within a range of 50–100 µm. The transition zone between UHMWPE and rubber is characterized by a smooth surface. No evidence of cracks or micro-tears between the polymer phases, which could potentially form during low-temperature splitting, was observed. This finding indicates the presence of favorable interfacial interactions, which can be linked to the observed enhancements in resistance to aggressive liquids and abrasion, as well as the improved tensile frost resistance coefficient. The supramolecular structure of rubber samples combined with HDPE is more pronounced and exhibits greater relief than that of the original rubber. This is indicative of a more uniform distribution within the matrix volume, which can be attributed to the high fluidity of the HDPE melt.Conclusions. Rubbers modified with UHMWPE, in comparison with HDPE, exhibit enhanced resistance to wear, oil, and frost, while maintaining their elastic and strength properties. It was established that rubber containing 15 pts. wt of UHMWPE exhibits optimal properties and can thus be recommended for use in sealing rubber products.

Improvement of the Thermoelectric Properties in CNT/Bi2Te3 Composite Films Due to Evolution of the Depletion Layer and Point Defects under the Pulse Current Field.

A carbon nanotube (CNT) composite is an effective method to improve the thermoelectricity of materials. However, the depletion layer between the CNT and thermoelectric (TE) material always decreases the contribution of CNT to the conductivity of the TE material. It is important to eliminate the depletion layer for improving the TE properties. Pulsed-electric-field (PEF) treatment was used to eliminate the depletion layer based on the atomic short-range diffusion on the interface of CNT and Bi2Te3. When the pulse current density is 30 A·dm-2, the CNT composite Bi2Te3 film has high mobility, a high carrier concentration, and a high effective mass due to no depletion layer and a low density of point defects. Both the resistivity and Seebeck coefficient improve in the CNT composite Bi2Te3 films by PEF treatment of 30 A·dm-2. The power density is 1.36 W·m-2 when the hot side temperature is 373 K. The maximum ZT value of this film is 1.66 at 513 K. Thus, the PEF is an effective way to achieve TE property enhancement in the composite films.

Experimental Research on the Tribological Behavior of Plastic Materials with Friction Properties, with Applications to Manipulators in the Pharmaceutical Industry

In this article, the authors present the results obtained within a complex experimental program that focuses on determining the tribological characteristics of the friction materials used in transmission belts, which are critical active components in manipulators within the pharmaceutical industry. The elements of transmission belts, having the role of ensuring the movement of cardboard packaging—used when packing the foils with medicine capsules—and stopping them during the insertion of the foils, were studied. This repetitive cycle—travel-braking—leads to the wearing of the friction material on the active surface of the belt. The experiments were carried out in a dry environment (air) by testing different types of friction materials (original belt, 3D printed TPU 60A, and TPU 95A). While the study is limited to these three materials, the results highlight the significant influence of material type and infill percentage on the coefficient of friction (COF) and wear resistance. TPU 60A achieved the highest COF at 100% infill, indicating a superior grip but experienced substantial wear, under the same conditions. Conversely, TPU 95A demonstrated a lower COF, suggesting reduced grip, but exhibited exceptional wear resistance. The aim of the research is to provide a preliminary investigation into the materials’ wear resistance and braking effectiveness. The experiments utilized appropriate samples to replicate real operational conditions, particularly focusing on the nature of contact between the moving belt and the packaging.

Heat transfer optimization using silver nanoparticle-stabilized nanofluids in copper heat pipes: comparative analysis of stabilizing agents

Abstract This study explores the thermal performance of copper heat pipes filled with surface-modified silver nanoparticle-stabilized nanofluids. The aim was to assess the effect of different nanoparticle surface chemistries on key heat transfer parameters such as thermal resistance and heat transfer coefficient (HTC). Five silver nanofluids stabilized by Polyethylene Glycol (PEG), Branched Polyethyleneimine (bPEI), Polyvinylpyrrolidone (PVP), Citrate, and Lipoic Acid were evaluated under heat inputs ranging from 50 W to 90 W and filling ratios of 60% and 70%. K-type thermocouples were used to measure temperature, from which thermal resistance and HTC were calculated. The bPEI-stabilized nanofluid demonstrated the best performance, reducing thermal resistance from 0.0540 °C/W at 50 W to 0.0420 °C/W at 90 W, while increasing HTC from 1680 W/m2 °C to 2320 W/m2 °C. Response Surface Methodology (RSM) confirmed that higher filling ratios and heat inputs significantly enhanced heat transfer. These findings highlight the potential of surface-modified silver nanofluids to improve thermal management systems, particularly in high heat flux applications. Further research is suggested to explore long-term stability and the scalability of these nanofluids for industrial use.

Hindered Sedimentation of Tungsten Carbide Particles in a Hydroxyl-Terminated Polybutadiene-Based Polymer-Bonded Explosive Energetic Composite System.

Energetic composite systems with uniform particle distributions are of considerable interest, but sedimentation is a persisting challenge. Tungsten carbide (WC, density: 15.36 g/cm3) particles are promising cemented carbide particles owing to their desirable properties. In this study, we investigated the mitigation of sedimentation in a polymer-bonded explosive (PBX) energetic composite by optimizing the viscosity and particle distribution using WC particles and a hydroxyl-terminated polybutadiene-based binder. A simulation based on a modified version of Stokes' law is used to study the sedimentation behaviors of the system at different viscosities, and the resistance coefficient of particle sedimentation is estimated. The PBX energetic composite system loaded with the WC particles is prepared and analyzed. In the early curing stages, when the resistance coefficient is 0.65-1.95 (×109), the sedimentation rate is low, but increases rapidly as the viscosity of the system increases. When the effective viscosity is ≥11,510 MPa·s, the particle sedimentation is improved. The energetic components are tightly entangled within the binder, with no exposure or agglomeration, and the WC particles are evenly distributed. The system can reach a solid content of 91% and retain its pourability. Thus, an energetic composite system loaded with high-density metal particles is prepared, providing a reference for use in PBX formulation.

Enhanced Tribological Performance of Laser-Textured TiN-Coated Ti6Al4V Alloy Surfaces: A Comparative Study with Untextured Surfaces

Titanium alloy is widely used as a biomaterial due to its strength, lightweight nature, and corrosion resistance. Despite its strength and lightweight nature, its low wear resistance limits its uses in prosthetic components. Laser surface texturing (LST) was used to improve the wear resistance of titanium alloys by creating textured surfaces before applying protective coatings. A biocompatible TiN composite protective coating was applied using physical vapour deposition (PVD) with a thickness of 4 µm. Response surface methodology (RSM) was used to predict the tribological properties by varying input parameters such as material type (TI, T2, T3, and T4), load in N, and sliding velocity in m/s. A pin-on-disc tribometer was used to conduct a unidirectional sliding wear test based on the RSM design. Tribological properties were studied to determine the impact of laser texturing on the bonding strength of the coating. As a result, material type T4 exhibits an improved coefficient of friction and specific wear resistance under varying sliding velocity and load conditions compared to other material types. The study was further supported by an ANSYS simulation, which revealed stress reduction affecting the coefficient of friction and, consequently, wear. The textured surface topography, wear mechanisms, and coating compositions were examined using scanning electron microscopy.

Computational simulation of the Aerodynamic performance of NACA2412 and NACA25112 in low Reynolds numbers

The present study introduces the basic definition of aerofoil and NACA series aerofoil. Then numerically investigates the two-dimensional aerodynamic characteristics of NACA 2412 and NACA 25112 aerofoils at a Reynolds number of 2. 0106. This study utilises the fluid dynamics simulation tool ANSYS Fluent, which is based on the finite volume method, to acquire the necessary data. The geometric model and grid of aerofoil were built with ANSYS Meshing and simulated with the pressure-based solver. In addition, the experimental environment of this study is the inlet speed of 30m/s and the air pressure of 1ATM. The study based on the Nabier-Strokes control equation completes simulation processing with SSTK-Omega. The aerodynamic characteristics of NACA2412 and NACA25112 were compared, including the pressure, velocity distribution map and the lift resistance coefficient change with the angle of attack. These experimental results are presented in the form of graphs. This experiment can be used for subsequent wind tunnel experiments or for developing a new aerofoil.

Analysis of the Tolerance of 22 Malus baccata Accessions to Alkali Stress

Alkali stress is an important factor that restricts the growth and yield of crops. Apple (Malus baccata Borkh.) rootstocks have attracted widespread attention because of their wide distribution and ability to exist in various forms. This study reported the tolerance of several M. baccata accessions to alkaline stress using the sand culture method. Nitrogen (N), phosphorus (P), and potassium (K) contents in the roots of 22 M. baccata accessions decreased after 40 days of alkali stress exposure. N and P contents in the leaves of most M. baccata seedlings decreased, whereas K content increased. In addition, the new leaf number and fresh and dry weights of the M. baccata accessions decreased significantly, indicating that alkali stress inhibits the growth of M. baccata seedlings. The 22 M. baccata accessions were divided into three categories: high, moderate, and low tolerance based on the cluster analysis of the resistance coefficients of six growth indices combined with the average resistance coefficient evaluation of the growth indices. These delineations are important for screening M. baccata resources. This study provides a basis for the growth of the apple industry in areas such as northwest China, which suffer from severe salinization.

Ultra-low reverse leakage NiOx/β-Ga2O3 heterojunction diode achieving breakdown voltage >3 kV with plasma etch field-termination

This work reports the fabrication and characterization of a NiOx/β-Ga2O3 heterojunction diode (HJD) that uses a metallic nickel (Ni) target to deposit NiOx layers via reactive RF magnetron sputtering and lift-off processing with >3 kV breakdown voltage, ultra-low reverse current leakage under high reverse bias, and a high junction electric field (>3.34 MV/cm). The heterojunction diodes are fabricated via bilayer NiOx sputtering followed by self-aligned plasma-etching for field-termination on both large (1-mm2) and small area (300/100-μm diameter) devices. The HJD exhibits an ∼135 A/cm2 forward current density at 5 V with a rectifying ratio of ∼1010. The minimum differential specific on-resistance was measured to be 17.26/11.64 mΩ cm2 (with/without current spreading). The breakdown voltage on a 100-μm diameter pad was measured to be greater than 3 kV with a noise floor-level reverse leakage current density (10−8 ∼ 10−6 A/cm2) up to 3 kV, accomplishing a parallel-plane junction electric field to be at least 3.34 MV/cm at 3 kV with a power figure of merit >0.52/>0.78 GW/cm2 (with/without current spreading). The temperature-dependent forward current density–voltage (J–V) measurements were performed from room temperature (25 °C) to 200 °C, which showed a temperature coefficient of resistance (α) of 1.56, lower than the value of SiC Schottky barrier diodes.

Fully printed all-resistive dual-mode sensor with ultra-low temperature coefficient of resistance for crosstalk-free detections of pressure and humidity

Fully printed all-resistive dual-mode sensor with ultra-low temperature coefficient of resistance for crosstalk-free detections of pressure and humidity

The calculation of fluid leaks in the peristaltic hydraulic machine

BACKGROUND: In the peristaltic pumps a significant gap can remain in the compressed working body, and therefore volumetric losses may significantly influence on the actual flow rate of the pump. The gap’s shape is determined by approximate dependencies or by numerical methods, but both of these approaches have their own drawbacks. AIMS: Using both theoretical dependencies and numerical methods, to determine parameters of the gap in the compressed pump’s hose and to calculate fluid leaks in the pump. MATERIALS AND METHODS: The object of this study is a peristaltic pump that uses a hose compressed by two rollers. The theoretical flow rate was determined according to the existing theory of positive displacement hydraulic machines, through the rotor speed and the volume of the working chambers. It was assumed that the hose in the pump body has the shape of a torus, and the SolidWorks Simulation software product was used to determine the shape of the gap in the compression region and the amount by which the volume inside the hose decreases due to compression by the roller. The resulting geometry of the deformed hose was transferred to the STAR-CCM+ computational fluid dynamics program, where the velocity field in the gap and the dependence of the gap resistance coefficient on the Reynolds number were obtained. For the final determination of leaks in the gap, the Weisbach formula for local losses in the gap and the Darcy-Weisbach formula for friction losses along the length of the pump hose were used. The Darcy coefficient was calculated assuming that the flow in the pump hose is laminar. RESULTS: Comparison of calculation results with experimental dependencies showed that the proposed leaks calculation method in the pump can be used at laminar flow and rotation speeds of the pump rotor not less than 100 min-1. CONCLUSIONS: The usage of theoretical dependencies and numerical methods to determine the gap’s parameters and to calculate leaks in the pump has shown its effectiveness, but for more accurate results, it is necessary to take into account additional factors due to the fact that the flow in the pump is non-stationary.

Pressure Drop Analysis of Turbine Housing Model with Circular Sliced Pipe for Micro Hydropower Generation

Energy independence is a government program aiming to meet society's energy needs evenly. Steps to increase energy independence in the new and renewable energy sector include hydro-energy generation. One of the important components of a hydro generator is the penstock pipe and turbine housing, which channels water and then pushes and drives (spins) the turbine with the flow of water to produce electrical energy. The turbine housing flow design innovation must provide a function as an optimal fluid conductor by minimizing the resistance that occurs when fluid flows towards the turbine housing and rotates the turbine optimally. The scope of this research includes analysis of the phenomenon of energy loss flowing in circular pipe slices in hydroelectric power plant turbine housings with influencing factors such as friction, turbulence, and flow resistance, as well as measuring the pressure drop in circular pipe slices. The model developed is a circular slice bend with angles of 180 degrees, 270 degrees, 360 degrees, and 450 degrees, taking into account the optimal curvature ratio (R/D) of 3.5. Based on previous research, 90-degree wedge bends with many slices (n_(90-degree)) 4 to 6 or  4 and pressure drop coefficient (C_(pd-th)) obtained 180-degree (0.333 – 0.200), 270-degree (0.445 – 0.277), 360-degree (0.527¬ – 0.339), 450-degree (0.587 – 0.390) with a bend length L, an elevation reduction angle  and a 1.5D upstream-downstream elevation difference to avoid contact between the upstream and downstream bends. The results obtained from this research are the slice modules that can be used and the resistance coefficient values that arise from the slice modules. The more slices selected according to the angle of inclination chosen, the smoother the resulting circular bend shape and the lower the resistance value, but the work will be more difficult. The most optimal slice module is the number of slices that allow its implementation, and the resistance coefficient is small. By knowing the optimal resistance coefficient value, the resulting pressure drop can be predicted to maximize the thrust to rotate the turbine.

Fabrication of Free-Standing Porous BaTiO Thick Films by Indirect Selective Laser Sintering

The fabrication of free-standing porous thick films of ferroelectric BaTiO3, using a laser-assisted technique, is presented as a novel alternative to conventional methods. This approach adapts Indirect Selective Laser Sintering (ISLS) to create green films in a single laser pass, avoiding the complexities of traditional processes. Using commercial BaTiO3 powder and polyamide 12 as raw materials, laser processing parameters such as scanning laser speed and power were optimized to produce green BaTiO3 thick films with different thicknesses. After laser processing, the films were conventionally sintered and characterized for phase composition, microstructure, porosity, and electrical properties. X-ray diffraction and Raman spectroscopy confirmed the tetragonal BaTiO3 phase, while mercury intrusion porosimetry revealed a bimodal pore distribution. Impedance spectroscopy demonstrated a positive temperature coefficient of resistivity (PTCR) effect, with a peak resistivity near the Curie temperature. The PTCR behavior is hypothesized to arise from better oxygen adsorption due to the porosity and oxygen vacancies generated during sintering by carbon residues from polyamide degradation. The results demonstrate that ISLS is a versatile technique for producing high-quality, free-standing porous ceramic thick films with potential for a wide range of applications.

Fe‐Vacancies Manipulate Kondo Screening States in the d‐Orbital Kondo Lattice of Fe3‐xGeTe2 (x = 0.07–0.54)

AbstractManipulating the electronic correlation is a long‐term issue in the Kondo regime. Based on the pioneer successes in many localized f‐orbital systems, further achievements in more itinerant d‐orbital systems will open up avenues for numerous systems to participate in enabling the understanding of the electron interactions toward quantum criticality. Here, by simply tuning the ratio of Fe vacancies (x) in d‐orbital Fe3‐xGeTe2 (x = 0.07–0.54), the effective mass of Kondo lattice (KL) Fe3‐xGeTe2 is modulated due to the change of spinless Kondo hole densities, through a series of scaling investigations including on the effective and spontaneous moments µeff and µspon, magnetic susceptibility χ, the Sommerfeld coefficient γ, and the resistivity coefficients A. By analyzing the Fermi liquid characteristics of KL via the two relations of AFL/γ2 and χ0Pauli/γ below T*, an orbital coupling between degenerate orbitals of local moment S and multiple conducting spins m are found. With increasing Fe vacancy concentration, the localization effect, and Kondo interactions can be manipulated simultaneously, and the change in 2S/m leads to a subtle over‐under‐over‐ Kondo screening states evolution in Fe3‐xGeTe2. This work expands the comprehension of Kondo screening and provides a facile method to control electron correlation.

Analysis of Technologies for Applying High-Entropy Coatings by Physical Deposition Method

Introduction. Modern tribology solves the problems of increasing the reliability of friction units through applying vacuum wear-resistant coatings by the physical vapor deposition (PVD) method. More than five thousand scientific papers are devoted to high-entropy alloys (HEA). However, an urgent question about the possibility of obtaining wear-resistant and antifriction high-entropy coatings (HEC) using the PVD method remains unsolved. Its solution opens up the possibility of using HEC in mechanical engineering. The presented article is intended to fill this gap. Research objectives are as follows: to identify the key results on the creation of HEC by such PVD methods as vacuum arc evaporation and magnetron sputtering, to establish tribological characteristics of PVD coatings.Materials and Methods. From November 2023 to February 2024, the authors analyzed materials published in the Web of Science, Elibrary, Scopus, Medline, CINAHL databases in the Russian and English languages.Results. At the first stage, the literature on the vacuum arc coating method was considered. The issues of creating a vacuum arc discharge, its technological features, disadvantages, as well as processes in the cathode region of the arc were studied. The conditions of existence of cathode spots, the influence of temperature on the erosion coefficient, and processes on the anode and substrate were noted. The dependence of the deposition rate on the value of the potential on the substrate was shown. Nitride and combined coatings obtained by vacuum-arc method were analyzed: TiN, TiCN, TiAlN, TiMoS, TiSiN, TiN/VN, TiAlN/DLC-Ti. At the second stage, the history of the magnetron sputtering method was presented; technological features, types of magnetrons and nitride coatings obtained in this way were described. The third stage was devoted to the five-stage process of forming the coating structure. Island, layer-by-layer, and mixed growth modes of coating were considered. A schematic representation of the fundamental processes of structure formation was given. Defects in vacuum coatings were noted. At the fourth stage, the HEC based on the HEA were presented. Parameters predicting the formation of a HEA solid solution were indicated. Six families of high-entropy alloys were considered. Modern high-entropy coatings obtained by vacuum arc and magnetron methods were evaluated. The results of studies of structural-phase and physico-mechanical properties were summarized in the form of a table. The data of tribological studies of high-entropy coatings were presented.Discussion and Conclusion. The literature on HEC describes the coating structure, physical and mechanical properties, and thermal stability. The authors of the presented article found a gap in the research of tribology of high-entropy coatings. From the known results, it can be concluded that these coatings are frictional. However, due to their high hardness and ductility, they exhibit high wear resistance. In addition, it is difficult to talk about their tribological purpose. To solve the issue of the possibility of using PVD coatings in mechanical engineering, attention should be paid to the development of compositions with high hardness, wear resistance, and low coefficient of friction. They can be operated in tribo-loaded nodes.

ENHANCING THE DAMPING BEHAVIOUR OF STEEL CRANE STRUC-TURES BY INTRODUCING A CONCRETE CORE

The potential use of steel tube confined concrete columns in crane structures is being explored as a means of enhancing damping during the movement of carrying and lifting machines. This is with a view to mitigating the impact of dynamic effects that may arise during operation. The results of experimental studies of tube confined concrete specimens for stability under central compression by static loading are given. This paper presents a methodology for dynamic tests of specimens, which is used to determine the damping ratio of vibrations and the inelastic resistance coefficient of composite materials. The results demonstrate that tube confined concrete specimens possess enhanced damping behaviour in comparison to steel and reinforced concrete structures. This observation suggests that they are an effective solution for load-bearing structures designed to support moving overhead cranes.

Research on the mechanism and prediction model of gas leakage and diffusion from shallow-buried natural gas pipelines

As a crucial component of urban lifeline projects, shallow-buried gas pipelines pose a significant threat to society and people's lives, as well as property in the event of a leakage accident. To investigate the diffusion mechanism of gas leakage out of pipelines, the CFD method is employed to establish a validated numerical model for gas diffusion in backfilled soil. The effects of operating pressure, burial depth, leakage direction of pipelines, and soil resistance coefficient were discussed. The calculated results indicate that the numerical model can accurately predicte the diffusion process and the resistance coefficient of methane in soil-sand, loam, and clay-based. It was found that the burial depth affects the speed of gas diffusion to the soil surface but has little impacts on the concentration distribution range. The diffusion process in the same type of backfilled soil was found very similar under varying pipeline operating pressures, though the pipeline pressure significantly impacts the diffusion range. The shape of the leaked gas cloud in the soil is affected by soil resistance, leak direction, and air buoyancy. A new diffusion model for methane leaking in soil was proposed by introducing two time-related concentration adjustment parameters to the existing natural gas diffusion model. The average error between the calculated results of the proposed diffusion model and the established numerical model was found to be within 10%.

Application of a Gyroid Structure for Thermal Insulation in Building Construction.

This paper concerns research into the use of 3D-printed gyroid structures as a modern thermal insulation material in construction. The study focuses on the analysis of open-cell gyroid structures and their effectiveness in insulating external building envelopes. Gyroid composite samples produced using DLP 3D-printing technology were tested to determine key parameters such as thermal conductivity (λ), thermal resistance (R) and heat transfer coefficient (U) according to ISO 9869-1:2014. In addition, the authors carried out a comprehensive analysis of the annual energy balance of four different residential buildings, including older and modern structures, using Arcadia software v9.0. The results showed that 100 mm-thick multi-layer gyroid structures achieve exceptionally low thermal conductivity (approximately 0.023 W/(m·K)), significantly outperforming traditional materials such as mineral wool or polystyrene foam in terms of insulation efficiency. These structures also have high mechanical strength and low density, making them both lightweight and highly durable. As a result of these properties, the structures studied represent a promising solution for designing energy-efficient buildings, effectively reducing heating energy demand and improv the overall energy balance of buildings.

Bitumen quantity reduction for stone mastic asphalt (SMA) – suitable material for the environment

This paper describes the mix design (recipe) for SMA that consists of aggregate obtained from stone with relatively high specific gravity and relatively high refractive index (LA>16) but which significantly reduces the amount of Bitumen. and in this case, it also reduces the amount of carbon emissions in the environment. For the production of stone mastic asphalt is used aggregate produced from stone with special mineralogical and petrographic characteristics. The aggregate used for the wearing course of the highway has a coefficient of resistance to crushing Los Angeles LA = 18 and a specific mass greater than 3000kg / m3. Los Angeles coefficient does not meet the standard requirements for the road layer with heavy traffic and the maximum bulk density is greater than the bulk density of ordinary aggregates used for this type of asphalt. Also, for the production of stone mastic asphalt SMA for the highway is used bitumen with additives in the amount of 4.6%, a quantity that is smaller than the amount of bitumen provided by the standard for stone mastic asphalt which is 6-7%. However, the designed mix with the aggregate produced from M.G quarry stone and with the amount of polymerized bitumen (with polymer additives) (4.6%) has met the requirements for SMA stone mastic asphalt it also increases its performance in protecting the environment.

Quick determination of water vapor permeability and water vapor resistance of plasters and putties

The existing methods for determining the coefficient of vapor permeability and vapor permeability resistance of plaster and putty materials are characterized by a long time of the experiment.This underlines the need to create a method for accelerated determination of these indicators, taking into account the simplicity of its practical implementation.The paper provides a detailed description of the proposed method, indicating experimental procedures and an algorithm for processing measurement results.The correspondence of the results of the determination of the vapor permeability coefficient by the accelerated method and according to GOST 25898–2020 is shown.