Extended Service Life Research Articles

PROSPECTS FOR THE USE OF COMBINED METAL-CUTTING TOOLS FOR THREADING

This article examines the use of combined metal-cutting tools for performing threading operations. The main purpose of the work is to analyze the effectiveness of using these tools in terms of improving accuracy, productivity and cost-effectiveness of processing. Combined tools show significant advantages over traditional methods, including reduced processing time, improved accuracy characteristics and reduced equipment maintenance costs. The design features and principles of operation of boring threaded cutters and threaded combs, as well as their impact on production processes and the quality of final products, are considered. Threading with the use of combined metal cutting tools allows you to integrate several technological operations in one cycle, which helps to increase efficiency and reduce basing errors. Experimental data confirm that the use of comb cutters contributes to a significant increase in processing accuracy and productivity, as well as reducing the time required to perform operations. Comparative analysis has shown that combined tools provide a higher quality of the thread being cut and an extended service life compared to traditional processing methods. Keywords: combined metalcutting tools, threading tools, boring threaded cutters, threaded combs, threading, productivity, processing quality.

Control of deposits on pipeline systems by the method of free oscillations

RELEVANCE. There are a large number of heat exchangers in operation enterprises that operate under various temperature conditions. Steam, hot water, heated products of oil refining and other industries, which may contain oxides of iron, aluminum, calcium sulfate silicates, etc., are used as a heating agent. The efficiency of the heat exchange equipment depends on the condition of the heating surfaces. Contamination of these surfaces with various deposits dramatically reduces the heat transfer coefficient, which leads to a significant increase in heat consumption. The nature of the deposits depends on the properties of the heating agent and the heated medium.THE PURPOSE. The purpose is to assess the possibility of controlling deposits on the surfaces of heat exchange equipment by the free oscillation method. The presence of deposits changes the mass of structures and, consequently, the natural frequencies of vibrations, the analysis of which can determine not only the presence and thickness of deposits, as well as their appearance.METHODS. The paper shows the results of experimental studies conducted using a hardware and software package and calculations of natural vibrations of the surfaces of heat exchange equipment in the ANSYS software package to identify their dependence on the thickness and density of deposits. A plate, a pipe, and a pressurized pipe were modeled as heat transfer surfaces.RESULTS. The results obtained experimentally and computationally coincided, and it was concluded that the free oscillation method makes it possible to determine not only the presence of deposits on heat exchange surfaces, but their thickness and appearance.CONCLUSION. The free oscillation method can detect deposits in a timely manner and monitor their condition, which in turn will, reduce overall operating costs, increase energy efficiency and extend service life.

Constructing a multilayered film β[sbnd]PbO2[sbnd]ZrO2 electrode for energy-efficient zinc electrowinning

The zinc electrowinning process demands considerable energy, prompting the quest for energy-efficient solutions to curtail costs. Hence, the development of energy-saving anode materials for zinc hydrometallurgy is an important issue. Herein, multilayered PbO2 film materials were prepared through thermal decomposition and composite electrodeposition, yielding a new PbO2–ZrO2 electrode featuring ZrO2 particles as the second phase for energy-saving zinc electrowinning. The introduction of ZrO2 leads to reduced PbO2 crystal size, heightened the specific surface area of the electrode, and preferential growth of crystal planes. Electrochemical tests underscore that the PbO2–ZrO2 electrode manifests a reduced charge-transfer resistance (Rct) and overpotential alongside a 46.15 % extension in service life compared to the pure PbO2 electrode. Simulated zinc electrowinning experiment affirms PbO2–ZrO2 electrode has a 3.63 % surge in the current efficiency and a substantial 244.61 kWh/t reduction in energy consumption relative to the traditional Pb–0.6wt%Ag anode. This study provides a strategic framework for designing and developing cost-efficient, cost-effective anode materials, promoting advancements in energy conservation and consumption reduction within zinc electrowinning processes.

A Shape Memory Polyurethane with Extended Service Life by Self-Healing and Recyclable Properties

A Shape Memory Polyurethane with Extended Service Life by Self-Healing and Recyclable Properties

Room-temperature self-healing polyurethane with superior mechanical properties based on supramolecular structure for flame retardant application

Self-healing polymers, with their ability to extend service life and conserve resources, have garnered significant attention across various fields due to their immense potential applications. However, most repairable polymers typically require high temperatures for repair, and their relatively weak mechanical properties limit their practical use. Moreover, the flammability of polymers not only poses safety hazards during use but also fails to meet specific requirements for flame retardancy in certain fields. Addressing these issues, this study successfully designed a reactive self-extinguishing room-temperature self-healing polyurethane (PU) by introducing hyperbranched catechol (DBPA) onto the PU main chain. The prepared self-healing PU elastomer (DPU) exhibited high tensile strength (∼51.2 MPa), outstanding toughness (∼119.0 MJ/m3), recyclability, and good flame retardancy. Through intermolecular and intramolecular multilevel hydrogen bonding, the prepared DPU0.6 achieved room-temperature self-healing with an efficiency of approximately 71.2 %. The results showed that the addition of trace amounts of DBPA (0.6 wt%) significantly enhanced the flame retardancy and thermal stability of DPU. Compared to DPU0, the heat release rate (HRR) of DPU0.6 decreased by approximately 13 %, the total heat release (THR) reduced by 18 %, and the time to ignition (TTI) was extended by 7 s (reduced by ∼ 21 %). This study not only provides insights into the synthesis and design of novel self-healing PU but also further expands the application scope of self-healing PU.

Cost savings associated with extended battery longevity in cardiac resynchronization therapy defibrillators (CRT-D)

BackgroundCardiac resynchronization therapy-defibrillators (CRT-D) are devices established as treatment for symptomatic heart failure patients at risk of sudden cardiac death. Battery depletion poses a significant clinical and economic burden; extended service life may reduce costs due to generator changes and associated complications. ObjectiveThis study estimated cost-savings associated with extended battery longevity in Medicare patients receiving CRT-D implantation. MethodsA decision tree was used to explore three battery capacities: 1.0 ampere-hours (Ah), 1.6Ah, and 2.1Ah. Yearly risk of all-cause mortality, device-related complications, and end of battery life were estimated. Over 6 years, estimated costs included device implantation, replacement, follow-up appointments, and complications. ResultsThe average total costs to Medicare over 6 years were $41,527, $48,515, and $56,647 per person (USD 2023) for the 2.1Ah, 1.6Ah, and 1.0Ah, respectively. The total per-person replacement cost for the 1.0Ah devices was more than 4 times that of the 2.1Ah devices ($20,126 versus $5,006). When extrapolated to the total number of CRT-D implants over a 6-year period, the difference in costs between 2.1Ah1.0Ah battery capacity exceeded $500 million. ConclusionExtended longevity CRT-D batteries demonstrate significant cost savings to Medicare over 6 years. These data indicate long-term economic considerations should be included in device selection.

Zwiększenie wytrzymałości zdalnie sterowanych zaworów suwakowych poprzez zastosowanie ulepszonego komponentu hermetycznego

In this study, the hermetic elements of a remote-controlled valve were scrutinized, leading to the development of an advanced hermetic unit. The primary focus was on assessing the wear resistance of this crucial component. Through meticulous analysis and experimentation, graphs illustrating wear speed and intensity over time were constructed, revealing a substantial increase in resistance compared to existing designs. Employing a combination of detailed analysis and methodical experimentation, graphical representations delineating the evolution of wear speed and intensity over time were generated. The results underscored a notable increase in resistance when compared to prevailing designs, exemplifying the heightened efficacy of the newly devised hermetic unit, which demonstrated higher durability, crucial for effective valve operation across diverse conditions. These findings signify a significant advancement in engineering, promising enhanced reliability and extended service life for valves utilizing this innovative technology. The implications extend to various industries reliant on such valves, offering improved performance and durability. Further studies, including physical experiments for surface reinforcement, can deepen the understanding of parameters such as temperature change, velocity, pressure distribution, specific heat, thermal conductivity, and turbulence dissipation over the improved valve construction’s hermetic elements. The trajectory of this research aligns with the objective of refining the design and optimizing the performance of the hermetic unit, ensuring its resilience under diverse and demanding operational environments. This comprehensive exploration not only lays the groundwork for the evolution of future advancements in valve technology but also holds the potential to substantially elevate efficiency and longevity across a wide array of industrial applications.

Comparative electrochemical properties of MO (ZrO2, V2O5) based polyaniline nanocomposites for high-performance supercapacitor applications

Due to its distinctive qualities, such as its moderate energy density, extended service life, rapid discharge–charge rates, and superior safety, supercapacitors (SCs) are gaining more and more attention. A zirconium oxide ZrO2 (Zr) and vanadium oxide V2O5 (VO) based PANI nanocomposites, denoted as (ZrP for ZrO2/PANI, and VOP for V2O5/PANI) are fabricated using hydrothermal technique in this research work. Morphological and phase investigations validated the random particle shapes with good crystallinity and purity of the samples. The N2 sorption/desorption isotherm reveals a mesoporous feature of the electrodes and the highest BET surface area (36.5 m2/g) with large electroactive sites, which offers abundant faradaic reactions for charge storage. The I-V characteristics confirm their excellent conduction capabilities as well. When utilized as electrodes for SCs in the three-electrode setup, the VOP composite electrode attains the highest capacitance of 1372 F g−1 at a scan rate of 5 mV s−1 compared with other active electrodes. Besides that, the VOP electrodes offer superior cyclic stability, with a retention rate of 94.28% even after 7000 consecutive charge/discharge cycles. It has been discovered that the in two electrode VOP asymmetric device exhibited remarkable specific capacitance of 651.36 Fg−1 at 5 mV s−1 demonstrating a significant capacitance retention of 87.6% over 6000 cycles. The results suggest that the material could be a good contender for electrode materials in supercapacitors.

A digital workflow for assessing lifespan, carbonation, and embodied carbon of reusing concrete in buildings

Concrete is the most used construction material, accounting for 8 % of global CO2 emissions. Various strategies aim to reduce concrete's embodied carbon, such as using supplementary cementitious materials, utilizing cleaner energy, and carbonation. However, a large potential lies in reusing concrete for new buildings in a Circular Economy, thereby closing material loops and avoiding CO2 emissions. This study focuses on the reuse of precast concrete elements. We present a digital workflow for assessing reuse by predicting the remaining service life, estimating CO2 uptake by natural carbonation, and calculating the embodied carbon savings of concrete reuse. Both carbonation rates from EN 16757 and our investigation were applied to a case study building. While EN 16757 rates suggest that most precast elements have reached the end of their service life, our assessment shows that these elements have a sufficient lifespan for reuse. Plaster and coverings significantly delay carbonation and extend service life. During the first service life following EN 16757, carbonation was 19,2 kg CO2/m3, whereas our prediction was 5,4 kg CO2/m3. Moreover, CO2 uptake during service life, including reuse, was less than 6 % of the embodied carbon. The climate benefits of reuse greatly exceeded those of carbonation. Furthermore, carbonation did not have a decisive influence when applying Cut-Off, Distributed, and End-of-Life allocations for assessing embodied carbon of re-used elements in subsequent life cycles. The digital workflow is useful in quickly assessing lifespan, carbonation, and embodied carbon of concrete. It can be leveraged as a decision-making tool when designing for reuse.

Smart structural health monitoring using computer vision and edge computing

Structural health monitoring (SHM) provides real-time data on the condition and performance of infrastructure, enabling timely and cost-effective maintenance interventions, and hence enhanced safety and extended service life. The computer vision-based non-contact sensor has emerged as a promising alternative to conventional contact-type sensors for structural displacement measurement and SHM. Many of the currently reported vision-based structural displacement measurement systems typically temporarily set up a video camera from a distance to the structure. The collected images or videos are usually stored locally and post-processed offline to obtain structural displacement responses, which is cumbersome and limited to short-term SHM applications. The recent development of technologies empowered by the Internet of Things (IoT) and edge computing has enabled real-time video processing and analysis at the source, minimizing latency, reducing bandwidth requirements, and enabling prompt decision-making, thereby enhancing efficiency and responsiveness compared to traditional offline video recording and processing systems. In this paper, an edge computing vision-based displacement measurement system (EdgeCVDMS) is developed. Video recording, processing, and displacement response identification are entirely performed on an edge device integrated with the vision-based displacement tracking algorithm, thereby greatly reducing the amount of data transmitted to the cloud server. The feasibility and applicability of the developed sensing system are experimentally validated on a laboratory-scaled transmission tower structure. The proposed EdgeCVDMS is cost-effective, easily deployable, and of great potential to be applied for the condition assessment of a larger population of aging civil infrastructure.

The influence of the addition of titanium oxide nanotubes on the properties of 3D printed denture base materials.

In this study, the effects of adding titanium dioxide nanotubes (TiO2) to 3D-printed denture base resin on the mechanical and physical properties of denture bases were examined for the first time. The specimens were digitally created using 3D builder software from Microsoft Corporation through computer-aided design. In accordance with the test specifications for transverse strength, impact strength, hardness, surface roughness, and color stability, specimens were designed and printed with certain dimensions following relevant standards. TiO2 nanotubes (diameter: 15-30 nm and length: 2-3 μm) were added to the 3D-printed denture base resin (DentaBase, Asiga, Australia) at 1.0% and 1.5% by weight. Flexural strength, impact strength (Charpy impact), hardness, surface roughness, and color stability were evaluated, and the collected data were analyzed with ANOVA followed by Tukey's post hoc test (α = 0.05). Field emission scanning electron microscopy (FESEM) and energy dispersive x-ray spectroscopy (EDX) mapping were used to evaluate the dispersion of the nanotubes. Compared with those of the control group (0.0 wt.% TiO2 nanotubes), the average flexural, impact, and hardness values of the 1.0 and 1.5 wt.% TiO2 nanotube reinforcement groups increased significantly. Both nanocomposite groups showed significant color changes compared to that of the pure resin, and there was a considerable reduction in the surface roughness of the nanocomposites compared to that of the control group. Adding TiO2 nanotubes to 3D-printed denture base materials at 1.0 and 1.5 wt.% could enhance the mechanical and physical properties of the material, leading to better clinical performance. In terms of clinical applications, 3D-printed denture base material has been shown to be a viable substitute for traditional heat-cured materials. By combining this with nanotechnology, existing dentures could be significantly enhanced, promoting extended service life and patient satisfaction while addressing the shortcomings of the current standard materials.

Effect of Melamine Formaldehyde Resin Encapsulated UV Acrylic Resin Primer Microcapsules on the Properties of UV Primer Coating.

Ultra-Violet (UV) coatings are widely adaptable of substrates and produce low emissions of volatile organic compounds. UV coatings can extend service life by adding self-healing microcapsules that restore integrity after sustaining damage. In this study, UV coating was used as a core material; microcapsules were produced and added to the UV coating to enhance its self-healing property, providing a good protection for both the UV coating and the substrate. UV primer microcapsules were prepared with UV primer as the core material and melamine formaldehyde resin as the wall material. The UV primer containing more than 98.0% solids content was mainly composed of epoxy acrylic resin, polyester acrylic resin, trihydroxy methacrylate, trimethyl methacrylate, and photo initiator. The preparation process of the UV primer microcapsules was optimized. Further, the UV coating was prepared with better UV primer microcapsules, and the effects of the UV primer microcapsules alongside the comprehensive properties of the coating were studied. The best preparation process for the UV primer microcapsules was as follows: the wall-core mass ratio was 1:0.50, Triton X-100 and Span-20 as emulsifiers with an HLB value of 10.04, the microcapsule reaction temperature was 70 °C, and the reaction time of the was 3.0 h. When the quantity of the UV primer microcapsules increased in the coating, color difference ΔE of the coating increased, gloss decreased, transmittance decreased, elongation at break increased and then decreased, roughness increased, and self-healing rate first increased and then decreased. When the addition of the UV primer microcapsules reached 2.0%, the color difference ΔE of the coating was 1.71, the gloss was 106.63 GU, the transmittance was 78.80%, the elongation at break was 3.62%, the roughness was 0.204 μm, and the self-healing rate was 28.56%, which were the best comprehensive properties of the UV primer. To improve the comprehensive properties of the UV coatings, the UV coatings were modified by a microcapsule technology, which gave the UV coatings a better self-healing property. The application range of microcapsules for the UV coatings was broadened. Based on the previous research of microcapsules in UV coatings, the results further refined the study of the effects of adding self-healing microcapsules to UV coatings using the UV coating itself as the core material.

Effects of Ni–Cr–Mo–Si–B prealloy additives on the properties of Fe-based diamond composites

In this study, Fe-based diamond composites with various Ni–Cr–Mo–Si–B prealloy additives were prepared using hot-press sintering, and the effects of the Ni–Cr–Mo–Si–B content on the relative density, bending strength, Rockwell hardness, and frictional wear properties of the Fe–Cu–Co–Sn matrix were investigated. Additionally, the effect of the composition of the Ni–Cr–Mo–Si–B additives on the interface between the matrix and diamond was studied. The Ni and Cr in the additives facilitated a tight bonding interface without notable gaps between the diamond and Fe–Cu–Co–Sn matrix. Considering the overall performance of the materials, the optimal addition of Ni–Cr–Mo–Si–B was determined to be 10 %, which resulted in notably improved comprehensive performance indicators of the Fe-based diamond composite materials. For example, diamond drill bits made with this formulation exhibited a wear ratio of 1600 mm/g and a penetration rate of 29.21 mm/min, representing increases of 29 % and 44.96 %, respectively, compared to those of drill bits without Ni–Cr–Mo–Si–B additives. Developing high-performance diamond drill bits with increased ROP and extended service lives to enhanced performance, efficiency, and cost-effectiveness in drilling operations across different industries, ranging from mining and construction to oil and gas exploration.

Biomass-derived dynamic polyurethanes: Enhanced self-healing and recyclability through reversible cross-linking

Chemically cross-linked polyurethanes (CCPUs), renowned for their superior solvent resistance, high strength, and exceptional thermostability, have emerged as extensively used polymeric materials. Despite their advantages, CCPUs face a significant limitation that their stable cross-linked structures can preclude healing and recycling once damaged. This limitation underscores the urgent need for a new CCPUs variant that offers self-healing and recyclability to extend service life. In this work, a new type of cross-linked polyurethanes (CPUs) was designed and synthesized by incorporating the biomass-derived castor oil (CO) as a cross-linking agent and dynamic disulfide bond into a traditional polyurethane without using any catalysts. These newly developed CPUs exhibit superior mechanical performance with an impressive tensile strength of 29.37 MPa and a remarkable maximum elongation at break of 769.9 %. Notably, our recycled CPU-2 can retain a tensile strength of 22.40 MPa and an elongation at break above 604.8 % even after four thermal recycling cycles. Furthermore, the addition of conductive carbon black (CB) into this CPU matrix imparts remarkable self-healing properties to the polyurethanes/carbon black composite (CPU-2/CB), activated solely by near-infrared light. This inventive approach effectively enhances the functionality of traditional CCPUs, broadening their application potential.

Dual defense against membrane fouling for efficient and sustainable oil/water separation on a novel super-hydrophilic/underwater superoleophobic and catalytic nanofibrous membrane

Membrane separation technology is widely recognized as an efficient method for treating organically polluted wastewater in virtue of high performance and straightforward operation. However, the practical application of membranes is inevitably confronted with contamination issues, presenting a major challenge in terms of fouling resistance. To address this issue, a defensive-offensive dual-defense strategy based on wettability and catalytic ability control is proposed. With this concept, a novel nanofibrous membrane with a unique structure was successfully prepared through polyacrylonitrile (PAN) electrospinning, pre-oxidation, CoFe Prussian blue analogue (PBA) and polypyrrole (PPy) modification, and calcination processes. For the passive defense mode, the as-prepared membrane has shown good underwater-superoleophobicity for various types of oils, good separation capability for corresponding oil–water emulsions with retention ratios of above 99 % and fluxes ranging from 231.5 to 1524.2 L·m−2·h−1·bar−1, as well as organic solvent (dimethylformamide, DMF) resistance. For the offensive defense mode, this membrane exhibits well catalytic degradation performance for refractory pollutants with the assistance of peroxymonosulfate (PMS), which is due to the membrane being decorated with catalytic nanoparticles that contain abundant encapsulated ultra-small Fe doped Co3O4 (∼2.28 nm), and that is much smaller than the size of the pristine PBA (∼33.8 nm). Notably, the surfactants present in oil-in-water emulsions are found to be the main cause of membrane fouling, where the cationic surfactants exhibit the most significant fouling effect, while the introduction of photo-Fenton-like catalysis can endow the membrane with excellent antifouling performance and extended service life, and nearly a fully recover of emulsion separation performance was achieved. Overall, this work paves pathways to the design of advanced membranes for sustainable wastewater treatment.

Novel bamboo-raft-type floating structure (BRT-FS) assembled by FRP reinforced concrete tubes: Conceptual design and analysis

To improve construction efficiency in offshore engineering and extend service life of offshore platforms, a novel bamboo-raft-type floating structure (BRT-FS) assembled by FRP reinforced concrete tubes is proposed. It comprises four fundamental components: concrete tube, carbon fiber-reinforced polymer (CFRP) cable, holding beam, and bellow. This paper presents the structure system and structure design of BRT-FS. Separating load-bearing and buoyant functions ensures structural safety and ease of design. It has broad application perspectives in offshore construction due to its high corrosion resistance, designability, construction efficiency, and low crack control requirement. Furthermore, to obtain the operation conditions of BRT-FS, the mechanical performance is analyzed from two levels, which are hydroelastic analysis and structural analysis. Hydroelastic analysis is conducted under different wave directions, wave periods, water depths, and structural dimensions using a new finite element-boundary element (FE-BE) method. In a specify study case, a sensitive period around 11 s for head sea, around 7 s for oblique wave, around 5 s for beam sea are noted. The hydroelastic response is not significantly affected by water depth or transverse dimension. Structural analysis indicates that the structure can work in clam harbour sea with breakwater protection. Even after concrete tubes crack in higher waves, this new structure can still float with the inside bellows in theory. These preliminary findings confirm the feasibility of this novel structure. Structural details such as tube-tube joints, tube-beam joints, CFRP cable anchorages, and other connections will be further designed and tested in the future.

Wheel Wear Modeling and Re-Profiling Strategy Optimization Based on the Maintenance Data of a Three-Axle Bogie Locomotive

Wear caused by wheel–rail contact forces is inevitable during vehicle operation, which has an important impact on the security and stability of train operation. Therefore, it is of great significance to study wheel wear patterns and optimize re-profiling strategies to extend service life. Based on the wheel wear data of three-axle bogie locomotives, this paper proposes a data-driven hybrid wheel wear model and optimization schemes of the re-profiling strategy. The wear model consists of a wheel flange thickness wear model, a wheel diameter wear model, and a re-profiling ratio coefficient model. Then, utilizing the above models, the optimization of the re-profiling strategy for different axle position wheels is raised, and the optimization of the complete vehicle re-profiling strategy is presented by considering the wheel diameter difference. Finally, a wheel data-driven analysis platform was developed to enable the management and utilization of wheel maintenance data. Analysis of extensive maintenance data indicates that the guide wheels wear the fastest, approximately 22.2% higher than the middle wheels, which wear the slowest. The re-profiling ratio coefficient model indicates that the ratio coefficient increases as the wheel flange thickness before re-profiling increases. Simulations demonstrate a longer expected wheel life with a flange thickness between 28 and 32.5 mm. Compared to measured values, the optimization strategy reduces complete vehicle re-profiling by 21.5%. Through the initial implementation at CRRC Dalian Locomotive Ltd, it has become evident that this methodology offers a viable solution to enhance the service longevity of locomotive wheels.

Effect of Ce on structural evolution and corrosion resistance of HRB500E rebar corrosion layer

HRB500E rebar is a low-alloy high-strength steel with excellent mechanical properties and good plasticity but suffers from deficient corrosion resistance. This can be solved by adding trace elements, including rare earth elements. Herein, the corrosion-resistant behavior of rebar was evaluated by weightlessness testing and electrochemical measurements, and the effects of Ce on the structural evolution of the corrosion product layer were investigated by scanning electron microscopy (SEM), Electron Probe X-ray Micro-Analyzer (EPMA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that adding Ce to the rebar improved the densification of the reinforcing surface corrosion products, as well as reduced the corrosion rate of the experimental rebar. Compared to C0 sample without Ce, the rebar sample containing 0.044 wt.% Ce displayed increased Ecorr by 0.051 V, decreased Icorr by 15.573 mA cm−2, enhanced Rc of the corrosion product layer by 112.71 Ω cm2, incremented α-FeOOH content in the corrosion product layer, and boosted ratio of α/γ* in the corrosion product layer by 10.11%. Furthermore, the oxide (CeO2) formed by Ce in the corrosion layer of the rebar bar surface existed in the rust layer, resulting in a stable corrosion product layer with improved blocking ability of the corrosive medium. Overall, the addition of Ce at certain ratios looks promising to produce HRB500E rebar with excellent corrosion resistance and extended service life under harsh conditions.

Evaluation of Slurry-Eroded Rubber Surface Using Gloss Measurement

Slurry erosion testing is essential for evaluating the durability of materials under erosive conditions. This study examines the slurry erosion behaviours of chloroprene rubber (CR) under varying impact conditions to assess its durability. Traditional mass loss methods and qualitative techniques, including microscopy, SEM, and AFM, were employed to analyse eroded CR samples. Results indicate that cumulative material loss in CR increases linearly with sand impingement after approximately 60 kg of sand and correlates with an impact energy of about 30 kJ. The highest erosion rate was found at an impact angle of 15°. Erosion mechanisms vary with impact angle, affecting surface topography from cutting and ploughing at lower angles to deformation and crater formation at higher angles. Despite their efficacy, these methods are time-intensive and costly. This paper presents a novel approach utilising gloss measurement for continuous, non-destructive monitoring of eroded rubber surfaces. Gloss measurements are 24 times faster than traditional mass loss methods. Correlating gloss values with cumulative material loss, steady-state erosion, and impact energy offers significant time savings and an enhanced understanding of the erosion process. Experimental results demonstrate the effectiveness of gloss measurement as a reliable tool in slurry erosion testing of rubbers. The quantitative output from gloss measurements could support proactive maintenance strategies to extend service life and optimise operational efficiency in industrial applications, particularly in the mining industry.

Comparative Testing of Asphalt Concrete for Fatigue Life Using Various Modern Laboratory Methods

Statement of the problem. At present, one of the most significant tasks in the road industry is the actua-lization of the methodology for designing flexible pavements. In order to ensure extended pavement service life, design issues are of particular relevance, which requires the improvement of existing and the development of new calculation criteria, one of which is the calculation of asphalt concrete layers for fatigue life. Results. Comparative tests of various types of asphalt concrete selected at road construction sites were carried out using modern laboratory methods to evaluate their fatigue properties. The dependences between the relative tensile deformation of asphalt concrete and the number of load application cycles during tests by various methods are obtained. Conclusions. Through the course of the research, possible reasons for the heterogeneity of the results obtained on four-point bending installations were identified. For further research, the indirect stretching method is set forth as the main method, as it provides greater uniformity and determinism of the results, and the four-point bending method is proposed to be considered as an additional one, confirming the results obtained with indirect stretching.