Search Results (106)

Urban expressways increasingly struggle with declining skid resistance and rising tire–pavement noise as asphalt surfaces age, yet few studies integrate friction, acoustic behavior, and permeability over multiple pavement types and service years. This research provides the first multi-year, multi-indicator field evaluation of four widely used surface systems in Korea (double-layer drainage asphalt, thin-layer low-noise overlays, SMA, and WC-6) linking wet-skid resistance (BPN), rolling friction (GN), acoustic metrics (LAeq, LAFmax), density evolution, and field permeability (Q) into a single performance framework. A three-year dataset from 2021–2024 (n = 20 sites) revealed that wheelpath friction deteriorated steadily at −1.77 BPN/year, with WC-6 exhibiting the fastest decline (≈−5.5 BPN/year) and drainage asphalt the slowest (≈–2.5 BPN/year). Predicted wheelpath service lives spanned 3.8–5.7 years across pavement types. Acoustic monitoring showed a consistent hierarchy (Drainage < Thin-Layer < SMA < WC-6), with WC-6 producing up to 20 dB higher LAFmax due to strong air-pumping effects. Permeability trends mirrored acoustic behavior, with Q decreasing 9–18% over 3 years but maintaining clear ranking: Drainage > Thin-Layer > SMA > WC-6. SMA NMAS analysis further showed that SMA-10 mm delivers higher initial friction but deteriorates faster than SMA-8 mm. Correlation analysis demonstrated that permeability governs both friction and noise (Q vs. LAeq: r = −0.84; Q vs. GN: r = +0.81), confirming the dominant mechanistic role of void connectivity. Collectively, the findings provide quantitative evidence that drainage and thin-layer systems deliver the most balanced long-term performance across safety, noise, and hydraulic functionality, offering practical guidance for pavement selection on noise-sensitive expressways. Full article

Asphalt pavements incorporating recycled and sustainable materials have become a widely adopted strategy in road construction, particularly with the use of reclaimed asphalt pavement (RAP) and crumb rubber (CR) derived from waste tires. However, the adhesion and cohesion characteristics of rubberized RAP mixtures remain insufficiently understood. This study investigates how interfacial bonding affects the rutting resistance and moisture susceptibility of rubberized RAP asphalt mixtures. Two RAP sources with different aging levels and two CR particle sizes (250 μm and 380 μm) were evaluated. Binder bond strength (BBS) tests showed that pull-off strength increased with the use of smaller CR particles and more highly aged RAP, while rotational viscosity and penetration tests confirmed the corresponding increase in binder stiffness. Hamburg wheel track (HWT) tests with high-temperature viscoplastic deformation analysis demonstrated improved rutting resistance in the tested mixtures. Furthermore, boiling tests supported by image analysis revealed reductions in stripping ratios, indicating enhanced moisture resistance. ANOVA results (p < 0.05) confirmed that CR content had a significant effect on bonding characteristics, whereas RAP aging and CR particle size jointly influenced rutting performance. Overall, mixtures incorporating 10% CR and 25% RAP achieved the best balance between adhesion, cohesion, and durability. These findings provide a quantitative understanding of how interfacial bonding governs the mechanical performance and moisture resistance of rubberized RAP mixtures. Full article

Background: The psychosomatic effects of stress are risk factors for a range of dental and systemic diseases. This study used the massive Japanese national statistics database to clarify the association of psychological stress with subjective symptoms and conditions requiring hospital visits. Methods: Anonymized data from 93,690 respondents of the 2019 Japanese survey were provided for this study. From these data, those of 29,777 respondents aged 40–89 years were classified into stress groups based on their responses to the Kessler Psychological Distress Scale (K6). The response rates for symptoms and diseases were compared and analyzed using contingency tables and binomial logistic regression. Results: The items with the largest odds ratios in the univariate analysis were depression/other mental disease (7.60), followed by irritability (6.86) and health perception QOL (6.31). Among those with subjective symptoms, the proportion in the high-stress group was higher (15.1%), with a univariate odds ratio of 3.17. The results of the binomial logistic regression analysis, with subjective QOL as the dependent variable, were as follows: The explanatory variables with the highest adjusted odds ratios were stress group classification (3.14), followed by feeling physically tired (2.44) and sleep satisfaction (2.22). The stress group was associated with subjective symptoms, such as irritability and depression/other mental diseases, as well as with social factors, such as household structure and work hours. These results suggest the existence of specific symptoms, diseases, and environmental factors associated with high stress. Conclusions: The results suggest that stress may have a substantial impact on quality of life in later life. Therefore, healthcare measures for older adults should focus on the symptoms and diseases that tend to be associated with stress to mitigate their effects. Full article

Background: The interplay between QoL and psychological distress may differ cross-culturally. The purpose of this study was to investigate the relationship between quality of life (QoL) and psychological distress, among an Egyptian Christian background sample. Methods: Participants completed QoL and K-10 questionnaires. Descriptive statistics, correlation analysis, and partial correlation controlling for age were conducted to explore these relationships. Results: The sample had a mean age of 50.64 years (SD ± 9.6) and was slightly male dominated (57.1%). QoL scores ranged from 4.23 to 5.52 on a 7-point scale, with the highest scores in personal relationships and the lowest in community engagement. K-10 scores indicated low to moderate psychological distress, with feeling tired without reason scoring highest. A significant negative correlation was found between QoL and K-10 scores (r = −0.354, p < 0.001), suggesting higher QoL is associated with lower psychological distress. Material comforts and health showed the strongest negative correlations with K-10 scores. The relationship between QoL and psychological distress remained significant after controlling for age (r = −0.347, p < 0.01). Self-awareness and self-expression emerged as key factors positively correlated with overall QoL. Conclusions: Enhancing QoL, particularly in areas of material comfort, health, and personal growth, may effectively reduce psychological distress. Interventions should be culturally tailored to respect linguistic and religious backgrounds. Further research with more diverse samples and longitudinal designs is recommended to deepen understanding of these relationships. Full article

The formation and evolution of galaxies and other astrophysical objects have become of great interest, especially since the launch of the James Webb Space Telescope in 2021. The mass, size, and density of objects in the early universe appear to be drastically different from those predicted by the standard cosmology—the $\mathsf{\Lambda }$CDM model. This work shows that the mass–size–density evolution is not surprising when we use the CCC+TL cosmology, which is based on the concepts of covarying coupling constants in an expanding universe and the tired light effect contributing to the observed redshift. This model is consistent with supernovae Pantheon+ data, the angular size of the cosmic dawn galaxies, BAO, CMB sound horizon, galaxy formation time scales, time dilation, galaxy rotation curves, etc., and does not have the coincidence problem. The effective radii $r_e$ of the objects are larger in the new model by $r_e\propto {\left(1+z\right)}^{0.93}$. Thus, the object size evolution in different studies, estimated as $r_e\propto {\left(1+z\right)}^s$ with $s=-1.0$ ± $0.3$, is modified to $r_e\propto {\left(1+z\right)}^{s+0.93}$, the dynamical mass by ${\left(1+z\right)}^{0.93},$ and number density by ${\left(1+z\right)}^{-2.80}$. The luminosity modification increases slowly with $z$ to 1.8 at $z=20$. Thus, the stellar mass increase is modest, and the luminosity and stellar density decrease are mainly due to the larger object size in the new model. Since the aging of the universe is stretched in the new model, its temporal evolution is much slower (e.g., at $z=10$, the age is about a dex longer); stars, black holes, and galaxies do not have to form at unrealistic rates. Full article

This study investigates the rheological and chemical effects of waste tire pyrolytic oil (TPO) and its encapsulation (POC) as rejuvenators for asphalt binders. Driven by the need for sustainable and effective strategies to Recycle Reclaimed Asphalt Pavement (RAP), we investigated the use of TPO in two forms: as a liquid additive and as polymer capsules. The capsules, made in a 1:5 mass ratio (one part polymer, five parts TPO), were assessed through two methods: rheological tests (dynamic modulus and phase angles) and chemical composition analysis (carbonyl and sulfoxide indices). The binders underwent three aging levels: unaged, primary aging (RTFO), and secondary aging (PAV). Five liquid TPO dosages (1%, 2%, 4%, 6%, 9% by weight) and three encapsulated TPO dosages (6%, 9%, 12% by weight) were tested. Results show that TPO reduces stiffness, increases viscous response, and lowers aging indices, with higher dosages enhancing the effect. Quantitatively, 9% liquid TPO restores PAV-aged binder to near-unaged conditions, suitable for RAP recycling, while 4% release from POCs achieves rejuvenation comparable to RTFO-aged binders, enabling self-healing applications. The estimated release of TPO from POCs during mixing was 20–40%, ensuring a gradual softening effect. These findings highlight the potential of TPO and POC in enhancing asphalt durability and recycling. Full article

Background: Chronic obstructive pulmonary disease (COPD) is a progressive condition leading to declining lung function, dyspnea, and reduced quality of life. Pulmonary rehabilitation (PR) remains a cornerstone in COPD management; however, access remains limited, with less than 3% of eligible patients participating. Inspiratory muscle training (IMT), especially through novel methods like the Test of Incremental Respiratory Endurance (TIRE), offers a potential home-based alternative to traditional rehabilitation services. Despite growing interest, a key knowledge gap persists: few randomized trials have directly compared TIRE with threshold loading IMT over extended, largely unsupervised home-based periods while concurrently evaluating inspiratory muscle endurance and adherence. This randomized controlled trial aimed to evaluate the long-term efficacy of TIRE IMT compared to traditional threshold IMT and sham training in COPD patients. The study also assessed adherence to these home-based interventions, focusing on unsupervised periods without additional motivational support. Methods: A total of 52 COPD patients were randomly assigned to one of three groups: TIRE IMT, Threshold IMT, or Sham IMT. The study consisted of an 8-week supervised Phase I followed by a 24-week unsupervised Phase II. Training details: TIRE—session template set to 50% of the day’s maximal sustained effort; 6 levels × 6 inspirations (total 36) with preset inter-breath recoveries decreasing from 60 s to 10 s. Threshold IMT—spring-loaded valve set to 50% MIP (re-set at week 4); 36 inspirations completed within ≤30 min. Sham—valve set to minimal resistance (9 cmH₂O); 36 inspirations within ≤30 min. Primary outcomes included changes in maximal inspiratory pressure (MIP) and sustained maximal inspiratory pressure. Secondary outcomes focused on adherence rates and correlations with functional capacity. Results: Of the 52 participants, 36 completed the study. Participant details: TIRE n = 12 (mean age 60.9 ± 12.9 years), Threshold n = 12 (67.4 ± 6.9 years), Sham n = 12 (67.3 ± 8.7 years); overall 21/36 (58%) men; mean BMI 30.0 ± 7.5 kg/m². The TIRE IMT group demonstrated significantly greater improvements in MIP (31.7%) and SMIP compared to both the Threshold and Sham groups at 24 weeks (p < 0.05). Despite a decline in adherence during the unsupervised phase, the TIRE group maintained superior outcomes. No adverse events were reported during the intervention period. Conclusions: In this randomized trial, TIRE IMT was associated with greater improvements in inspiratory muscle performance than threshold and sham IMT. While adherence was higher in the TIRE group, it declined during the unsupervised phase. The clinical interpretation of these findings should consider the relatively wide confidence intervals and modest sample size. Nevertheless, the mean change in MIP in the TIRE arm exceeded a recently proposed minimal important difference for COPD, suggesting potential clinical relevance; however, no universally accepted minimal important difference exists yet for SMIP. Further adequately powered trials are warranted. Full article

Background: University students are vulnerable to depression due to the transitional nature of their life stage, which often involves increased academic pressures and social changes. This study aims to examine the prevalence, symptoms, and associated risk factors for depressive symptoms among undergraduate students at non-medical universities. Methods: This cross-sectional study was conducted at non-medical universities in Mwanza Region, Tanzania. A self-administered, structured questionnaire was used to collect the data. The presence and severity of depressive symptoms were assessed using the Beck Depression Inventory (BDI-II). Results: A total of 768 students participated in the study. The prevalence of depressive symptoms was 35.7%. A significant proportion experienced loss of interest and pleasure (n = 516; 67.2%), felt easily tired (n = 373; 48.6%), and had difficulty making decisions (n = 303; 39.4%). A significant relationship was observed between age and depressive symptoms, with participants aged 25 and above reporting higher rates of depressive symptoms (53.2%) compared to those aged 18–24 (28.8%) (p < 0.001). Similarly, the year of study was significantly associated with depressive symptoms; fourth-year students had the highest proportion of depressive symptoms (64.3%), while first-year students had the lowest proportion (26.2%) (p < 0.001). Conclusion: This study found that over one-third of undergraduate students in non-medical universities suffer from depressive symptoms. This high prevalence rate highlights an urgent need for targeted mental health interventions within university settings to prevent long-term academic, social, and psychological consequences. Campus counseling services should prioritize screening for key symptoms while developing stress-management programs tailored to academic progression challenges. Full article

Heavy metals are a major cause for concern in relation to water systems, due to their high toxicity at elevated levels. The metals can originate from both natural processes, including geological weathering and volcanic activity, as well as anthropogenic activi-ties such as industrial discharges, agricultural runoff, mining, and urbanization, which significantly contribute to water pollution and environmental degradation. The as-sessment of these risks is crucial for protecting public health, especially in populations reliant on contaminated water sources. Exposure to such contaminants can result in severe health consequences, including neurological impairments, organ deterioration, and an elevated risk of cancer. To conduct this assessment study, six surface water sampling sites were selected (i.e., S1 (Gobia), S2 (Kouamefla), S3 (Benkro), S4 (Dou-kouya), S5 (Doka), and S6 (Zengue)) due to their proximity to mining activities. We used the hazard quotient (HQ) and hazard index (HI) methods to estimate the levels of non-carcinogenic health risk associated with heavy metals. Then, the assessment of carcinogenic health risk was carried out using the Incremental Lifetime Cancer Risk (ILCR) methods. First, the highest ILCR total values were observed in the Doya locality (i.e., 0.4237 for the children and 0.5650 for the adults) and during the great dry season (i.e., 0.4333 for the children and 0.5743 for the adults). These findings highlight that populations in this locale experience heightened exposure during the period of the Great Rainy Season. The results indicated that the population exposed to Cd and Hg may experience health concerns irrespective of season and locality. For As and Pb, risks are present in both seasons (i.e., Short Dry Season (SDS) and Short Rainy Season (SRS)). On the other hand, the HIs are well above 1, indicating that the population may be exposed to non-carcinogenic diseases associated with the metals, regardless of the season or locality. To further explore the results, the assessment by ILCR was em-ployed, which demonstrated that for all the designated localities, the ILCRs of As and Cd are well above 10⁻⁴ for the entire population, indicating that the population con-suming this water may develop major carcinogenic risks. In addition, the highest ILCR values were obtained for Cd, regardless of the age group. It should be noted that sea-sonal variation had no significant effect on the trend in ILCRs determined for the en-tire population. Full article

The cement industry faces increasing energy costs and environmental pressures, driving the adoption of alternative fuels derived from waste materials. In Togo, approximately 350,000 t of end-of-life tires (ELT) are generated annually, creating significant environmental and health hazards through uncontrolled disposal and burning practices. This study investigated the technical feasibility and economic viability of incorporating waste tires as an alternative fuel in cement manufacturing. Tire-derived fuel (TDF) performance was evaluated by comparing pre-processed industrial tires with unprocessed ones, focusing on clinker production loss, elemental composition, heating values, and bulk density. The results demonstrate that TDF exhibits superior performance characteristics, with the highest heating values, and meets all the required specifications for cement production. In contrast, whole tire incineration fails to satisfy the recommended criteria, necessitating blending with conventional fuels to maintain clinker quality and combustion efficiency. The investigation revealed no significant adverse effects on production processes or clinker quality while achieving substantial reductions in nitrogen and sulfur oxide emissions. The experimental results were compared with the theoretical burnout times to optimize the shredding operations and injection methods. However, several challenges remain unaddressed, including the absence of streamlined handling processes, limited understanding of long-term ecological and health impacts, and insufficient techno-economic assessments. Future research should prioritize identifying critical aging points, investigating self-rejuvenating behaviors, and quantifying long-term environmental implications. These findings provide a foundation for developing computational models to optimize the mixing ratios of alternative and fossil fuels in cement manufacturing, offering significant environmental, economic, and societal benefits for the cement industry. Full article

Natural rubber is a widely used biological polymer material because of its excellent comprehensive performance. Nevertheless, the performance of domestic natural rubber cannot meet the requirements for high-end products such as aviation tires, which has become a constraint on the innovation and upgrading of high-end manufacturing enterprises and the enhancement of global competitiveness in China. To solve the bottleneck problem of natural rubber processing technology, this study systematically analyzed the effects of different varieties of fresh latex ratios on the processing and dynamic properties of bio-coagulated natural rubber. By mixing PR107 and Reyan72059 fresh latex with Reyan73397 fresh latex according to proportion, the fresh latex was coagulated by enzyme-assisted microbials, and the effects of the fresh latex ratio on physical and chemical indexes, molecular weight distribution, vulcanization characteristics, processing properties, cross-link density and physical and mechanical properties of the natural rubber were analyzed. The results showed that the aging resistance of natural rubber coagulated with enzyme-assisted microbial decreased, and the aging resistance of natural rubber increased with the increase in the mixing ratio of PR107 and Reyan72059 fresh latex. The proportion of high molecular weight of the natural rubber coagulated with the enzyme-assisted microbial increased, and the fresh latex mixing had little effect on the molecular weight distribution curve. Under the carbon black formulation, the CRI of the enzyme-assisted microbial coagulated natural rubber compound was relatively larger. Under the same strain conditions, the H-3 compound (PR107:Reyan72059:Reyan73397 = 1:1:3) had the best viscoelasticity and the least internal resistance of rubber molecules. In addition, the cross-link density, tensile strength, elongation at break, and tear strength of H-3 vulcanized rubber were the largest, improved by 23.08%, 5.32%, 12.45% and 3.70% compared with the same H-2 vulcanized rubber. In addition, the heat generation performance was reduced by 11.86%, and the wear resistance improved. Full article

This study explores the innovative use of recovered tire-derived aggregates in cement-based mortars to enhance thermal insulation and reduce environmental impact. The research addresses the pressing global challenge of managing end-of-life tires (ELTs), which are non-biodegradable and contribute significantly to waste management issues. By incorporating crumb rubber from recycled tires into mortars, this study investigates the feasibility of creating lightweight, thermally insulating mortars suitable for building repair and rehabilitation. The primary objective is to develop mortars that minimize structural load, decrease energy consumption in buildings, and promote the recycling of ELTs as a valuable resource. The study focuses on evaluating how varying crumb rubber content affects key properties such as workability, thermal conductivity, compressive strength, and fracture energy. Experimental tests were conducted to assess these properties, with the results indicating that mortars with up to 50% crumb rubber content exhibit improved thermal insulation and meet industry standards for non-structural repair applications. The methodology involved creating eight different mortar mixtures with varying proportions of crumb rubber particles (ranging from 0% to 100%). Each mixture was tested for physical and mechanical properties, including density, workability, air content, setting time, thermal conductivity, and strength. The experimental results showed that as the crumb rubber content increased, the thermal conductivity of the mortars decreased, indicating enhanced insulation properties. However, higher crumb rubber content led to reduced mechanical strength, highlighting the need for a balanced approach in material design. Key findings reveal that the air content of early-age mortar paste increases linearly with the crumb rubber replacement ratio, impacting the hardened behavior by concentrating stresses or facilitating the infiltration of damaging elements. The study also establishes relationships between mortar properties and crumb rubber content, contributing to the development of sustainable construction materials. The environmental benefits of recycling ELTs are emphasized, as this practice reduces the reliance on natural sand, a resource that is the second most consumed globally after water. This study underscores the viability of using crumb rubber from recycled tires in mortars for repair and rehabilitation purposes. The developed mortars, particularly those with 25% to 50% crumb rubber content, show promise as non-structural repair products, offering improved thermal insulation and reduced environmental impact. Full article

Rubber materials enter aquatic environments by stormwater runoff via sources such as playground mulch, athletic fields, and roadway surfaces. Tire rubbers are considered plastics as they comprise a substantial portion of synthetic polymers. Rubber particles are complex and variable depending on the type, source, and age of rubber. In this study, zebrafish embryos and daphnids were exposed to nano-scale or micro-scale particles, or leachate from recycled rubber (RR), crumb rubber (CR), and cryo-milled tire tread (CMTT). Zebrafish embryos were evaluated for lethal and sub-lethal effects over a 120 h exposure, while daphnids were tested over a 48 h period. Nano-scale RR, CR, and CMTT particles elicited a hatch delay in zebrafish embryos with similar EC₅₀ values (1.3 × 10⁹–1.4 × 10⁹ particles/mL). Micro-scale particles did not elicit any significant effects in developing zebrafish. Nano-scale particles of all rubber materials significantly increased hatch delay compared to leachate, suggesting an adverse nanoparticle effect unexplained by chemical leaching alone, indicating tire particle-specific effects. Daphnia RR micro- and nanoparticle exposures resulted in mortality, with LC₅₀ values of 9.8 × 10⁵ microparticles/mL and 5.0 × 10⁸ nanoparticles/mL, respectively. Leachate exposures did not elicit significant Daphnia mortality. Sublethal micro- and nano-TP exposures significantly decreased microalgae ingestion by Daphnia after 24 h. The effects of tire-derived exposures observed pose a risk to aquatic organism survival at environmentally relevant concentrations. Full article

Infraorbital groove and hollowness are common aging-related anatomical changes in the periorbital region, leading to a sunken and tired appearance. These conditions are caused by the progressive loss of volume in the deep fat pads, including the sub-orbicularis oculi fat (SOOF) and malar fat, along with skin thinning and decreased elasticity. Filler injections, particularly hyaluronic acid-based fillers, are the preferred treatment to restore volume and smooth the under-eye area. Proper diagnosis, understanding of anatomical variations, and accurate injection techniques are essential to avoid complications and achieve natural, esthetically pleasing outcomes. Treatments should consider the patient’s unique anatomy and potential adjunctive procedures to ensure balanced and harmonious facial rejuvenation. Full article

Sandy soils are a type of geomaterial that may require improvements due to lack of cohesion. In this study, first, the lack of cohesion of sand was resolved using clay, and the soil was stabilized with cement and lime (4% and 3% of the dry weight of materials, respectively) and finally reinforced with recycled tire fibers of 20 to 30 mm in length for improved strength and ductility. Next, 747 samples with different fiber contents at different curing temperatures and ages were prepared and a unconfined compressive strength (UCS) test was carried out. Next, a novel approach employing multivariate nonlinear regression techniques and obtained empirical data was applied to formulate a mathematical model for predicting the UCS and the modulus of elasticity (E_s) of the reinforced and stabilized soil. This model can serve as a valuable tool for building engineers in designing building foundations. The comparison of the obtained UCS and E_s results and those predicted using the proposed model showed a correlation of >95% (R² ≥ 0.95). The fibers effectively increased the failure strain, thus resulting in the greater ductility of the samples. As an example, in 14-day samples cured at 60 °C with 0%, 0.4%, 1%, 1.7%, and 2.5% fibers, the failure strain showed an incremental trend of 1.47%, 1.87%, 2.08%, 2.20%, and 2.92%, respectively. Scanning electron microscopy (SEM) was used to study the microstructure of the samples and to explain the strength experimental outcomes. SEM images showed a desirable interaction between the fiber surfaces with the soil mass and the reduction in porosity and the occurrence of pozzolanic reactions through stabilization. The results also showed that the reinforcement effectively improved the ductility, as desired for building foundations; however, it resulted in reduced strength, although a greater strength compared to the untreated soil was achieved. Although soil stabilization has been widely studied, limited research focuses on stabilizing soil with clay, lime, cement, and recycled tire fibers. This study offers design engineers an estimation scheme of the strength properties of stabilized and reinforced foundations. Full article