Search Results (115)

Listeria monocytogenes biofilms on surfaces that come into contact with food create ongoing challenges in produce-processing environments, highlighting the necessity for effective surface sanitation. This research examined the effectiveness of chlorine (200 ppm), quaternary ammonium compound (QAC, 400 ppm), and UV-C light (0.85 J/cm²) against L. monocytogenes biofilms developed on stainless steel, polyethylene terephthalate (PET), and silicone rubber materials frequently used in apple packing settings. Biofilms were cultivated using a mixture of LCDC and V7 strains in diluted apple juice and evaluated after 1 and 7 days of growth. The type of surface material and the age of the biofilm had a significant impact on the performance of the sanitizing agents (p < 0.05). Chlorine achieved a reduction of 2.84 ± 0.06 log CFU/coupon on 1-day-old biofilms on stainless steel, although its effectiveness dropped to 1.90 ± 0.07 log CFU/coupon on biofilms aged 7 days. Similar trends were noted for QAC (2.42 ± 0.05 to 1.73 ± 0.06 log CFU/coupon) and UV-C (2.71 ± 0.05 to 1.57 ± 0.08 log CFU/coupon) over time. PET and silicone rubber consistently exhibited lower log reductions than stainless steel for all treatments. The presence of organic matter from apple juice reduced the efficacy of sanitizers on all surfaces. These results emphasize the significant role of surface material, biofilm age, and organic load on sanitation effectiveness, offering practical recommendations for enhancing the control of L. monocytogenes in produce-processing facilities. Full article

As by-products rich in flavonoids and phenolic compounds, onion peels are globally undervalued and often discarded. This study reports the synthesis of carbon quantum dots (CQDs) from onion peels and evaluates their antimicrobial effectiveness against key foodborne pathogens and biofilms on common food contact surfaces, including plastic, stainless steel, and rubber. The CQDs exhibited a quasi-spherical shape with particle sizes ranging from 1.7 to 9.0 nm and contained abundant oxygen- and nitrogen-functional groups, as confirmed by FT-IR and XPS analyses. The CQDs showed significant antimicrobial activity, with minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against Salmonella typhimurium, Escherichia coli O157: H7, Listeria monocytogenes, and Staphylococcus aureus of 2200/2800 µg/mL, 1400/2000 µg/mL, 1200/1800 µg/mL, and 400/600 µg/mL, respectively. Time-kill assays confirmed these results. In biofilm tests, S. typhimurium formed biofilms more easily than L. monocytogenes. Washing with CQD solution for 5 min reduced biofilm presence by 81.6–91.5% for S. typhimurium and over 74% for L. monocytogenes, with more than 94% reduction after 10 min of treatment (over 94% for S. typhimurium; 95.8–98.8% for L. monocytogenes) across all surfaces, especially on plastic and stainless steel. These findings indicate that onion peel-derived CQDs are promising, eco-friendly agents for disrupting biofilms and turning undervalued waste into valuable products. Full article

High-friction surface treatments (HFSTs) are widely applied to improve pavement safety by enhancing long-term skid resistance. Although epoxy resins are commonly used due to their strength and durability, their high cost, susceptibility to delamination, incompatibility with substrates of flexible pavements, and adverse environmental concerns limit their long-term performance. This study presents crumb rubber modified (CRM) asphalt as a sustainable alternative binder for HFST applications. CRM binders offer high performance and compatibility with existing pavement surfaces, cost effectiveness and reduced environmental impacts as compared to epoxy binders. In addition, the binder development utilizes enhanced recycling technologies for interacting with used tire rubber with asphalt. The evaluated CRM binders were prepared under varying interaction temperatures, crumb rubber contents, and types. The developed binders were evaluated for friction performance with two aggregate sources, calcined bauxite (CB) and rhyolite (Rhy). Binder characterization included rheological testing conducted through both frequency sweep and temperature sweep procedures. HFST mixes were evaluated using the British Pendulum Test (BPT), the Dynamic Friction Tester (DFT), and the Circular Track Meter (CTM) in collaboration with the Three-Wheel Polishing Device (TWPD) to simulate the traffic-induced polishing effect. The results showed that CRM content influenced binder performance under polishing. CRM asphalt-based HFST with a relatively high CRM content (15%) maintained a greater coefficient of friction (COF) and exhibited polishing resistance, showing low reduction in the COF after the total number of polishing cycles. In contrast, mean profile depth (MPD) analysis revealed that the most macrotexture efficiency was found in binders with a lower CRM content (10%) after completing the total number of polishing cycles. Analysis of Variance (ANOVA) showed a significant effect of the interaction conditions and rheological properties of CRM binders on the British pendulum number (BPN) loss due to the polishing process. As expected, aggregate source further influenced the resistance to polishing; CB outperformed Rhy with significantly lower aggregate loss under polishing. Overall, the results confirmed that CRM asphalt binders can effectively serve as a sustainable, flexible, and cost-effective alternative binder in HFST. Full article

Silicon (Si)–containing compounds, such as silica (SiO₂), play a crucial role as fillers, binding phases, and linking agents in sustainable materials. Coating biochar with SiO₂ can enhance its performance as a carbon-negative filler in composites such as bioplastics, rubber, asphalt, and cement, making it more competitive with conventional fillers. Biochar, derived from biomass pyrolysis, contains a high concentration of biogenic SiO₂—typically 50–80% of its total inorganic content. However, conventional extraction methods such as solvent extraction or gasification detach SiO₂ from the biochar matrix, leading to energy-intensive and environmentally unfavorable processes. The objective of this study was to develop an environmentally friendly and energy-efficient approach to induce the migration of embedded biogenic SiO₂ from within biochar to its surface—without detachment—using ultrasonic treatment. Fifteen biochar samples were produced by pyrolyzing five biomass types (sugarcane bagasse, miscanthus, wheat straw, corn stover, and railroad ties) at 650, 750, and 850 °C. Each sample was subsequently subjected to ultrasonic irradiation in an isopropanol–water mixture for 1 and 2 min. Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analyses confirmed that ultrasound treatment significantly enhanced SiO₂ migration to the biochar surface, with up to a 2.5-fold increase in surface Si and O concentrations after 2 min of sonication. The effect was most pronounced for biochar synthesized at 850 °C, corresponding to higher surface porosity and structural stability. Fourier Transform Infrared (FTIR) spectroscopy revealed an increased intensity of the Si–O–Si asymmetric stretching band at 1030 cm⁻¹, indicating surface enrichment of siloxane networks and rearrangement of Si-containing functional groups. Overall, the results demonstrate that ultrasound-assisted treatment is a viable and sustainable technique for enhancing SiO₂ surface concentration and modifying the surface chemistry of biochar. This SiO₂-enriched biochar shows potential for advanced applications in soil amendment, CO₂ capture, water purification, and as a reactive additive in cementitious and asphalt composites. Full article

Bamboo fibers have received significant attention due to their biodegradability and environmental benefits. However, their inherent hydrophilicity causes dramatic degradation in mechanical properties after water absorption. Some methods have been adopted to treat bamboo fiber to address this challenge, e.g., sodium hydroxide (NaOH) solution treatment, vegetable oil treatment, and carboxylated styrene butadiene rubber (XSBR) treatment. In this study, the sodium silicate solution treatment method is proposed. The effects of four treatment methods on bamboo fibers are systematically evaluated using direct tensile tests, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results indicate that all four treatment methods can effectively mitigate the reduction in tensile stress and Young’s modulus of bamboo fibers after water immersion. Sodium silicate solution (modulus = 3.3)-treated bamboo fibers show the smallest reduction in tensile strength (36.8%), while the Young’s modulus of the sodium silicate solution (modulus = 2.3)-treated fibers increased by 4.5%. FTIR analysis shows that four treatment methods lead to reduction in hydrophilic groups in bamboo fiber. For the sodium silicate solution treatment method, a hydrophobic solidified sodium silicate layer forms on the surface of bamboo fibers, which further hinders moisture absorption. Full article

Rubber chips, when used as a partial replacement for coarse aggregates in concrete, tend to increase ductility, absorb energy, and can be beneficial due to their ability to reduce impact forces and dampen vibrations. However, they lead to a substantial decrease in compressive strength compared to ordinary concrete. Due to the weak bond between rubber particles and the concrete matrix, sand-coating surface treatment was applied to enhance the interfacial properties of the rubber surface. In this research, a detailed numerical analysis was conducted in order to predict the mechanical and dynamic behavior of concrete by incorporating partially replaced coarse aggregates with uncoated and sand-coated rubber chips. The study also seeks to examine the effects of rubber inclusion on key parameters such as damping ratio and compressive strength, thereby providing insights into the effectiveness of using recycled rubber as a sustainable alternative material in concrete production. The compressive strength and damping ratio of concrete were examined through a three-dimensional numerical simulation using ABAQUS/CAE 6.14-1. The results demonstrated that the optimal compressive strength was achieved with a 15% sand-coated rubber replacement, resulting in a 15.67% increment. Furthermore, the maximum improvements in damping ratios were observed to be 48.42% for uncoated rubber chips and 25% for coated ones, when compared to conventional concrete. These enhancements highlight the potential of both coated and uncoated rubber inclusions, due to rubber’s high elasticity. Moreover, at optimized levels, improved concrete properties can be achieved while promoting sustainability through material reuse. Full article

The increasing demand for sustainable construction materials has underscored the limitations of conventional interlocking paving blocks (IPBs), particularly regarding durability, mechanical performance, and environmental impact. To overcome these shortcomings, this study proposes an integrated strategy of incorporating various waste materials in the production of IPBs namely: Untreated and surface-treated crumb rubber (CR) as a partial sand replacement at levels of 10%, and 20%; ceramic powder (CP) and glass powder (GP) as cement partial replacement at levels of 10%, 20%, and 30%, recycled ceramic as a full replacement of dolomite; and discrete fibers (basalt, polypropylene, and glass). A series of experimental tests was conducted to assess the slump, compressive and flexural strengths, water absorption, abrasion resistance, and microstructure of the proposed IPBs. The results of this study revealed that while untreated CR reduced workability and strength, it enhanced flexural resistance. Surface treatments of CR using CP and GP improved bonding and reduced porosity, with 20% CP yielding the best performances of 17.3% and 20% increases in compressive and flexural strength, respectively. Among fibers, 0.6% basalt fiber offered optimal strength and abrasion resistance (0.20 mm), while 0.6% polypropylene fiber achieved the lowest water absorption (3.70%) and a minimum abrasion depth of 0.28 mm at TR20CP mix. Microstructure analyses confirmed denser microstructure and stronger interfacial bonding in treated and fiber-reinforced mixes. This work offers a scalable, waste-based enhancement strategy for producing more durable and sustainable production of IPBs. Full article

This review surveys theoretical frameworks developed to describe rubber contact and friction on rough surfaces, with a particular focus on tire–road interaction. It begins with classical continuum approaches, which provide valuable foundations but show limitations when applied to viscoelastic materials and multiscale roughness. More recent formulations are then examined, including the Klüppel–Heinrich model, which couples fractal surface descriptions with viscoelastic dissipation, and Persson’s theory, which applies a statistical mechanics perspective and later integrates flash temperature effects. Grosch’s pioneering experimental work is also revisited as a key empirical reference linking friction, velocity, and temperature. A comparative discussion highlights the ability of these models to capture scale-dependent contact and energy dissipation while also noting practical challenges such as calibration requirements, parameter sensitivity, and computational costs. Persistent issues include the definition of cutoff criteria for roughness spectra, the treatment of adhesion under realistic operating conditions, and the translation of detailed power spectral density (PSD) data into usable inputs for predictive models. The review emphasizes progress in connecting material rheology, surface characterization, and operating conditions but also underscores the gap between theoretical predictions and real tire–road performance. Bridging this gap will require hybrid approaches that combine physics-based and data-driven methods, supported by advances in surface metrology, in situ friction measurements, and machine learning. Overall, the paper provides a critical synthesis of current models and outlines future directions toward more predictive and application-oriented tire–road friction modeling. Full article

A green and cost-effective method was employed to efficiently synthesize conductive silica–silver (SiO₂/PCPA/Ag) core–shell structured microspheres. The SiO₂ microspheres were initially functionalized with poly(catechol-polyamine), followed by the in situ reduction of Ag ions to Ag nanoparticles on the surface of the SiO₂ microspheres using an electroless plating process. Analysis using scanning electron microscopy confirmed the successful formation of a dense and uniform silver layer on the surface of the SiO₂ microspheres. The valence state of the silver present on the surface of the SiO₂ microspheres was determined to be zero through analyses conducted using an X-ray photoelectron spectrometer and X-ray diffractometer. Consequently, the SiO₂/PCPA/Ag microspheres, upon initial preparation, demonstrated a notable conductivity of 1005 S/cm, which was further enhanced to 1612 S/cm following additional heat treatment aimed at rectifying defects within the silver layer. The resulting rubber composites displayed a low electrical resistivity of 5.4 × 10⁻³ Ω·cm and exhibited a significant electromagnetic interference (EMI) shielding effectiveness exceeding 100 dB against both X-band and Ku-band frequencies, suggesting promising potential for utilization as a material for conducting and EMI shielding purposes. Full article

Triclosan (TCS), a persistent antimicrobial and endocrine-disrupting compound, is commonly found in surface and groundwater due to incomplete removal by conventional wastewater treatment. This study evaluated its fate in authentic rainwater runoff collected from a state road using rubber tiles made from recycled tires that were either uncoated (RRT) or coated with TiO₂ via the sol–gel method (SGT). Pollutants were analyzed by a high-resolution liquid chromatography–quadrupole time-of-flight mass spectrometry system (LC/MS QTOF) before and after treatment in a flat-plate cascade reactor under UV-A irradiation. After 120 min SGT achieved >50% TCS removal, while RRT achieved ~44%. Further analysis identified degradation products (chlorocatechole, quinone, and transient dioxin-like species). ECOSAR predictions indicated moderate to high toxicity for some degradation products, but their transient and low-abundance detection suggests that photocatalysis suppresses accumulation, ultimately yielding less harmful products such as benzoic acid. These findings highlight the dual role of TiO₂-coated rubber tiles: improving material durability while enabling photocatalytic degradation. Full article

Polymeric biocomposites are emerging as a new generation of eco-friendly and cost-effective materials that provide sustainable alternatives for the polymer industry while supporting environmental conservation. This study investigates the mechanical behavior of Low-Density Polyethylene (LDPE) compounds blended with natural rubber (NR) and reinforced with silanized Sugarcane Bagasse Ash (SCBA), chemically modified with bis(3 triethoxysilylpropyl) tetrasulfide (TESPT). Blends were formulated in LDPE/NR-SCBA weight ratios (wt%) of 90/10, 70/30, and 50/50, and processed at mixing speeds of 40 and 80 rpm to evaluate their potential as thermoplastic additives. Mechanical testing showed that blends mixed at 80 rpm achieved an 86% increase in elongation, while those processed at 40 rpm demonstrated a 78% enhancement in tensile strength. The incorporation of NR and vulcanizing systems markedly improved the overall mechanical properties of the composites. These biocomposites present promise for applications in the footwear industry (especially for soles) and for ergonomic molded components by conferring the advantageous combination of mechanical performance and esthetic appeal. Furthermore, development supports innovative manufacturing processes and contributes to reducing the industry`s carbon footprints, mitigating its negative impact on the planet. Full article

The aim of this study was to evaluate and compare the surface roughness and gloss—both initially and after simulated toothbrushing—of three 3D-printed crown materials subjected to different surface treatments: varnishing, polishing with diamond-impregnated rubber polishers, and polishing with a bristle brush and paste. Disc-shaped specimens (n = 90) were 3D-printed using three commercially available crown resins (Rodin Sculpture, VarseoSmile TriniQ, and OnX Tough 2) and post-processed per manufacturers’ instructions. Specimens were divided into three surface treatment groups: application of a light-cured varnish, polishing with a two-step diamond-impregnated rubber polisher, or polishing with a bristle brush and abrasive paste. Surface roughness and gloss were measured after treatment and again following 20,000 cycles of simulated toothbrushing. Additional specimens were prepared for Vickers microhardness testing and determination of filler weight percentage (wt%). Statistical comparisons were performed using two-way ANOVA with significance set at p < 0.05. Results: The varnish provided the statistically lowest roughness of all surface treatments for all materials. The bristle brush and abrasive paste polishing protocol produced the greatest gloss for the softest material (VarseoSmile TriniQ) and lowest gloss for the hardest material (Rodin Sculpture), whereas the two-step diamond-impregnated rubber polisher produced an equivalent gloss on all materials. Following toothbrushing, roughness was minimally affected; however, gloss was considerably reduced. Conclusions: All tested polishing and varnishing methods achieved clinically acceptable surface roughness (Ra < 0.2 µm) that persisted after simulated toothbrushing. Notably, the two-step diamond-impregnated rubber polisher produced consistent gloss across all materials, while the bristle brush and abrasive paste polishing protocol performed better on softer materials, and varnish application resulted in equal or superior gloss and roughness retention compared to polishing. Full article

Aiming at the problems of serious pavement temperature diseases, low efficiency and high loss of ice-breaking methods, high occupancy rate of waste tires and the low utilization rate and insufficient durability of rubber particles, this paper aims to improve the service level of roads and ensure the safety of winter pavements. A pavement material with high efficiency, low carbon and environmental friendliness for active snow melting and ice breaking is developed. Firstly, NaOH, NaClO and KH550 were used to optimize the treatment of rubber particles. The hydrophilic properties, surface morphology and phase composition of rubber particles before and after optimization were studied, and the optimal treatment method of rubber particles was determined. Then, the optimized rubber particles were used to replace the natural aggregate in the polyurethane gel mixture by the volume substitution method, and the optimum polyurethane gel dosages and molding and curing processes were determined. Finally, the influence law of the road performance of RPGM was compared and analyzed by means of an indoor test, and the ice-breaking effect of RPGM was explored. The results showed that the contact angles of rubber particles treated with three solutions were reduced by 22.5%, 30.2% and 36.7%, respectively. The surface energy was improved, the element types on the surface of rubber particles were reduced and the surface impurities were effectively removed. Among them, the improvement effect of the KH550 solution was the most significant. With the increase in rubber particle content from 0% to 15%, the dynamic stability of the mixture gradually increases, with a maximum increase of 23.5%. The maximum bending strain increases with the increase in its content. The residual stability increases first and then decreases with the increase in rubber particle content, and the increase ranges are 1.4%, 3.3% and 0.5%, respectively. The anti-scattering performance increases with the increase in rubber content, and an excessive amount will lead to an increase in the scattering loss rate, but it can still be maintained below 5%. The fatigue life of polyurethane gel mixtures with 0%, 5%, 10% and 15% rubber particles is 2.9 times, 3.8 times, 4.3 times and 4.0 times higher than that of the AC-13 asphalt mixture, respectively, showing excellent anti-fatigue performance. The friction coefficient of the mixture increases with an increase in the rubber particle content, which can be increased by 22.3% compared with the ordinary asphalt mixture. RPGM shows better de-icing performance than traditional asphalt mixtures, and with an increase in rubber particle content, the ice-breaking ability is effectively improved. When the thickness of the ice layer exceeds 9 mm, the ice-breaking ability of the mixture is significantly weakened. Mainly through the synergistic effect of stress coupling, thermal effect and interface failure, the bonding performance of the ice–pavement interface is weakened under the action of driving load cycle, and the ice layer is loosened, broken and peeled off, achieving efficient de-icing. Full article

Background: Healthcare-associated infections (HAIs) significantly increase morbidity, mortality, and healthcare costs. Among HAIs, catheter-associated infections are particularly prevalent due to the susceptibility of catheters to microbial contamination and biofilm formation, especially with prolonged use. Biofilms act as infection reservoirs, complicating treatment and often requiring catheter removal, thus extending hospital stays and increasing costs. Recent technological advances in catheter design have focused on integrating antifouling and antimicrobial coatings to mitigate or prevent biofilm formation. Methods: We developed COPESIL^®, a novel silicone rubber embedded with PEGylated copper nanoparticles designed to reduce microbial contamination on catheter surfaces. We conducted in vitro assays to evaluate the antimicrobial and antibiofilm efficacy of COPESIL^® against pathogens commonly implicated in catheter-associated urinary tract infections. Additionally, the safety profile of the material was assessed through cytotoxicity evaluations using HepG2 cells. Results: COPESIL^® demonstrated substantial antimicrobial activity, reducing contamination with Escherichia coli and Klebsiella pneumoniae by >99.9% and between 93.2% and 99.8%, respectively. Biofilm formation was reduced by 5.2- to 7.9-fold for E. coli and 2.7- to 2.8-fold for K. pneumoniae compared to controls. Cytotoxicity assays suggest the material is non-toxic, with cell viability remaining above 95% after 24 h of exposure. Conclusions: The integration of PEGylated copper nanoparticles into a silicone matrix in COPESIL^® represents a promising strategy to enhance the antimicrobial properties of catheters. Future studies should rigorously evaluate the long-term antimicrobial efficacy and clinical safety of COPESIL^®-coated catheters, with a focus on their impact on patient outcomes and infection rates in clinical settings. Full article

The use of low-temperature antibacterial technology is a processing method designed to preserve the biological activity of milk to the greatest extent. Traditional feeding and milking practices result in high levels of microbiological contamination of raw milk after extraction, mainly from cows and milking equipment, especially rubber cups. Ultrasonic treatment combined with antimicrobial agents combine cleaning and antibacterial technology, compared with traditional cleaning methods, more efficiently and in a environmentally friendly way. In this study, the technique was demonstrated to significantly reduce the total amount of bacteria in raw milk through simulation experiments on the surface of milking cups. It was shown that ultrasound-coupled slightly electrolytic water has a good potential for application in reducing bacterial contamination in the milk extraction process on farms. We investigated the synergistic mechanism of ultrasound (US) and slightly acidic electrolytic water (SAEW) and verified the bactericidal effect of milking cups. A 20 s treatment of milking cups with US (100 W) and SAEW (90 mg/L) led to an antibacterial rate of over 90%. The bactericidal mechanism causes fragmentation of the cell membrane of pathogenic bacteria, exudation of their intracellular contents such as nucleic acids and proteins, and increases in ROS. Full article