Search Results (6,642)

The effective management of waste-activated sludge (WAS) presents a significant challenge for wastewater treatment plants (WWTPs), primarily due to the sludge’s high content of organic matter, pathogens, and hazardous substances such as heavy metals. As urban populations and industrial activities expand, the increasing volume of WAS has intensified the need for sustainable treatment solutions. Conventional approaches, such as landfilling and anaerobic digestion, are frequently ineffective and resource-intensive, particularly when dealing with the protective extracellular polymeric substances (EPS) that render WAS resistant to biodegradation. Thermal pretreatment methods have gained attention due to their ability to enhance the biodegradability of sludge, improve dewaterability, and facilitate resource recovery. These processes function by breaking down complex organic structures within the sludge, thereby increasing its accessibility for subsequent treatments such as anaerobic digestion. The integration of thermal treatment with chemical methods can further optimize the management process, resulting in higher biogas yields, reduced pathogen content, and lower environmental risks. While thermal disintegration is energy-intensive, advancements in energy recovery and process optimization have made it a more viable and environmentally friendly option. This approach offers a pathway to more sustainable and efficient sludge management practices, which align with the goals of reducing waste and complying with stricter environmental regulations. Full article

Fluorosilicone was combined with aluminum trihydrate (ATH) to induce synergistic flame-retardant and thermal-resistant properties. The surface of ATH was modified with four different silane coupling agents. The flammability and mechanical properties of the fluorosilicone/ATH composites were assessed using an UL94 vertical test and a die shear strength test. The change in shear strength was investigated under aging for 1000 h at −55 °C and 150 °C. Pure fluorosilicone had inherent fire resistance and thus achieved a V-0 rating even at 20 wt.% ATH loading. Upon addition of ATH treated with 3-glycidoxypropyl trimethoxysilane, the composites exhibited the highest shear strength of 3.9 MPa at 23 °C because of the additional crosslinking reaction of fluorosilicone resin with the epoxide functional group of the coupling agent. Regardless of the types of coupling agents, the composites exhibited similar flame retardancy at the same ATH content, with a slight reduction in shear strength at 180 °C and 250 °C. The shear strength of the adhesives gradually decreased with aging time at −55 °C, but increased noticeably from 3.9 MPa to 11.5 MPa when aged at 150 °C due to the occurrence of the additional crosslinking reaction of fluorosilicone. Full article

This paper presents a recent investigation into the electromechanical behavior of thermally reduced graphene oxide (rGO) as a strain sensor undergoing repeated large mechanical strains up to 20.72%, with electrical signal output measurement in multiple directions relative to the applied strain. Strain is one the most basic and most common stimuli sensed. rGO can be synthesized from abundant materials, can survive exposure to large strains (up to 20.72%), can be synthesized directly on structures with relative ease, and provides high sensitivity, with gauge factors up to 200 regularly reported. In this investigation, a suspension of graphene oxide flakes was deposited onto Polydimethylsiloxane (PDMS) substrates and thermally reduced to create macroscopic rGO-strain sensors. Electrical resistance parallel to the direction of applied tension (x^) demonstrated linear behavior (similar to the piezoresistive behavior of solid materials under strain) up to strains around 7.5%, beyond which nonlinear resistive behavior (similar to percolative electrical behavior) was observed. Cyclic tensile testing results suggested that some residual micro-cracks remained in place after relaxation from the first cycle of tensile loading. A linear fit across the range of strains investigated produced a gauge factor of 91.50(Ω/Ω)/(m/m), though it was observed that the behavior at high strains was clearly nonlinear. Hysteresis testing showed high consistency in the electromechanical response of the sensor between loading and unloading within cycles as well as increased consistency in the pattern of the response between different cycles starting from cycle 2. Full article

This paper presents and demonstrates the development of a new lightweight coating for aluminum alloy from a novel multicomponent alloy based on the AlSiMgCu system. The coating was applied using a newly designed approach that combined high velocity oxy-fuel (HVOF) and plasma spraying processes. This hybrid technique enables the deposition of coatings with enhanced performance characteristics. The optical microscopy (OM) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM + EDS) revealed a strong adhesion and compaction between the multicomponent coating and the A6061 substrate. The new coating improved hardness by 50% and increased electrical conductivity by approximately 3.3 times compared to the as-cast alloy. Corrosion tests showed a lower corrosion rate, comparable to thermally treated A6061 alloy. Tribological tests indicated over 20% reduction in friction and over 50% reduction in wear rate. This suggests that multicomponent aluminum coatings could improve automotive and parts in contact with hydrogen by enhancing hydrogen fragilization resistance, corrosion resistance, electrical conductivity, and wear properties, with further optimization of thermal spraying potentially boosting performance even further. Full article

Metallum Fire-Resistant paint, denoted as MFR henceforth, represents a cutting-edge insulating material with dual functionality as a fireproof solution, presenting substantial advantages in the realm of construction applications. This exposition derives its primary insights from the scholarly contributions documented in publications. The focal point of these investigations includes the assessment of fire hazards associated with polyethylene materials in building structures and the enhancement of mortars in high-temperature environments in tunnels. The purpose of this study is to evaluate the effectiveness of a modified cork-based coating (MFR) compared to traditional coatings in terms of corrosion protection, fire resistance, and thermal insulation properties in construction applications. This evaluation focuses on quantifying the efficacy of MFR by examining key properties, such as adhesion, the reduced thickness required for fire protection, thermal conductivity reduction, and corrosion resistance under extreme environmental conditions. MFR is highly effective in fire prevention for buildings and tunnels, withstanding temperatures over 1000 °C while maintaining structural integrity. A unique aspect of MFR is its use of cork shavings, a typically underutilized byproduct from wine-bottle-stopper production. This innovative not only amplifies MFR’s fire-resistant attributes, but also introduces sustainability and judicious resource utilization into its manufacturing processes. Full article

This paper investigates the structural performance of novel steel-plate concrete containment structures, focusing on third-generation nuclear power plants. To address the challenges of increased complexities and costs associated with double-layer containment designs, this study explores the potential of steel-plate concrete structures to enhance safety, economic efficiency, and construction simplicity. The steel-plate concrete structure, characterized by its core concrete and dual steel plates, shows superior compressive strength, bending resistance, and elastoplasticity. Extensive numerical analyses, including finite element modeling and thermal-stress coupling, were conducted under various load conditions. Under structural integrity test conditions, the maximum radial displacement observed was 24.59 mm. Under design basis conditions, the maximum radial displacement was 47.61 mm; under severe accident conditions, it was 53.83 mm. The ultimate bearing capacity was 0.91 MPa, 2.17 times the design pressure. This study concludes that the steel-plate concrete containment structure maintains a high safety margin under all tested conditions, with stress and strain well within acceptable limits. It can effectively serve as a robust barrier against radioactive leakage and malicious impacts, providing a viable alternative to conventional containment designs. Full article

Buckwheat and other grains have become influential in sustainable agriculture and food security owing to climate change. However, subpar storage conditions can result in the deterioration of the nutritional value and active components of buckwheat, making storage quality a significant research subject. This study examined common buckwheat (CB) and Tartary buckwheat (TB) stored at 4 °C, 30 °C, and 55 °C from 0 to 6 months to assess storage quality and its relationship to the preservation of active components. The results of agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) showed that as storage temperature and time increased, both CB and TB exhibited the following differences: significant alterations in color due to an increase in browning index (B.I.), higher acidity from accelerated acid production at high temperatures, and a decrease in total phenolics, flavonoid content, and antioxidant capacity due to thermal degradation of functional components. In the storage quality assessment, no alteration in microstructure or degradation in components was detected after exposure to all times and temperatures, and the content of the primary bioactive compound, rutin, was CB (16.57–27.81 mg/100 g d.w.) and TB (707.70–787.58 mg/100 g d.w.), demonstrating buckwheat’s resistance to microbial contamination. Storage temperature significantly impacts buckwheat’s quality and bioactive components, making it an important element in establishing a sustainable food supply chain. Full article

We report the investigation of silicon nanoparticle composite anodes for Li-ion batteries, using a combination of two nm-scale atomic force microscopy-based techniques: scanning spreading resistance microscopy for electrical conduction mapping and contact resonance and force volume for elastic modulus mapping, along with scanning electron microscopy-based energy dispersion spectroscopy, nanoindentation, and electrochemical analysis. Thermally curing the composite anode—made of polyethylene oxide-treated Si nanoparticles, carbon black, and polyimide binder—reportedly improves the anode electrochemical performance significantly. This work demonstrates phase segregation resulting from thermal curing, where alternating bands of carbon and silicon active material are observed. This electrode morphology is retained after extensive cycling, where the electrical conduction of the carbon-rich bands remains relatively unchanged, but the mechanical modulus of the bands decreases distinctly. These electrical and mechanical factors may contribute to performance improvement, with carbon bands serving as a mechanical buffer for Si deformation and providing electrical conduction pathways. This work motivates future efforts to engineer similar morphologies for mitigating capacity loss in silicon electrodes. Full article

Nitrile Butadiene Rubber (NBR) is widely used as a sealing material due to its excellent mechanical properties and good oil resistance. However, when using NBR material, the seal structure is unable to avoid the negative effects of rubber aging. Hence, the influence of oil and thermal aging on the characteristics of NBR seals was studied by coupling the mechanical behavioral changes with the tribological behavioral changes of NBR in oil and the thermal environment. For this paper, aging testing and compression testing of NBR were carried out. Additionally, friction testing between friction pairs under different aging times was carried out. The surface morphology of the NBR working surface under different aging conditions was also observed. Finally, coefficients of different test conditions were introduced into the finite element model of NBR seals. It can be seen from the results that the elastic modulus increased with the increase in aging time in the thermal oxidative aging testing. The elastic modulus after 7 days of thermal oxidative aging increased by 135.45% compared to the unaged case, and the elastic modulus after 7 days of oil aging increased by 15.03% compared to the unaged case. The compression set rate of NBR increased significantly with the increase in aging time and temperature. The coefficient of friction (COF) between friction pairs increased first and then decreased with the increase in aging time. The maximum contact pressure decreased by 2.43% between the shaft and sealing ring and decreased by 4.01% between the O-ring and groove. The proportion of the effective sealing area decreased by 3.05% between the shaft and sealing ring and decreased by 6.11% between the O-ring and groove. Furthermore, the sealing characteristics between the O-ring and groove were better than those between the shaft and sealing ring. Full article

The study developed a large emission area of flexible blue organic light-emitting diodes (BOLED) on a polyethylene terephthalate/ Indium tin oxide (PET/ITO) substrate using a polycyclic skeleton ν-DABNA Thermally Activated Delayed Fluorescence (TADF) material. Initially, a 1 × 1 cm² blue OLED was fabricated to optimize the layer thickness. The blue OLED structure consisted of PET/ITO/HATCN/TAPC/UBH-21:ν-DABNA/TPBi/LiF/Al. However, as the emission area increased to 3.5 × 3.5 cm², the current density decreased due to the resistance of PET/ITO, leading to luminance non-uniformity. To address this issue, auxiliary Au lines were added to the ITO anode to enhance current injection. Despite this, when the Au lines reached a thickness of 30 nm, average light emission was disrupted. To improve the luminescence characteristics of large-area PET/ITO OLEDs, a capping and planarization layer of PEDOT:PSS was applied. Grid uniformity revealed a significant increase in overall luminance uniformity from 74.1% to 87.4% with the addition of auxiliary Au lines. Further increases in grid line density slightly reduced uniformity but enhanced brightness, resulting in brighter, flexible, large-area blue OLED lighting panels. Full article

Yb-doped Y₂O₃ stabilized ZrO₂ (YbYSZ) coatings, developed through solution precursor plasma spraying (SPPS), are engineered to resist calcium–magnesium–alumino–silicate (CMAS) infiltration by leveraging their unique micro-nano structures. This provides superior anti-wetting properties, crucial for preventing CMAS penetration at high temperatures. The investigation focused on the structural and compositional changes in YbYSZ-SPPS coatings subjected to prolonged thermal exposure at 1300 °C. Results indicate that while the coatings undergo significant sintering, leading to densification and microstructural evolution, the elemental composition and phase stability remain largely intact after up to 8 h of heat treatment. Despite some reduction in CMAS resistance, the coatings maintained their overall protective performance, demonstrating the potential of SPPS coatings for long-term use in high-temperature environments where CMAS infiltration is a concern. These findings contribute to the development of more durable TBCs for advanced thermal protection applications. Full article

A random copolymer (PTBM), utilized as deep ultra-violet (DUV) photoresist, was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization with tert-butyl methacrylate (tBMA), methyl methacrylate (MMA), triphenylsulfonium p-styrenesulfonate (TPS-SS), and functional poly (sesquicarbonylsiloxanes) (POSS-MA) as the monomer components, and 4-cyano-4-[(dodecylsulfanylthiocarbonyl) sulfanyl]pentanoic acid (CDSPA) as the RAFT reagent. Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H NMR) proved successful synthesis. Ultraviolet absorption spectroscopy (UV) analysis verified the transparency of the polymer in the DUV band. RAFT polymerization kinetics showed that the polymerization rate conformed to the first-order kinetic relationship, and the polymerization process exhibited a typical controlled free radical polymerization behavior. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and static thermo-mechanical analysis (TMA) showed that the incorporation of POSS groups improved the thermal properties of the copolymer. According to scanning electron microscopy (SEM) images, the copolymerization of photoacid monomers (TPS-SS) resulted in photoresist copolymers exhibiting good resistance to acid diffusion and low roughness. Full article

This study explores the feasibility of using Cu/AZO thin films as low-emissivity materials with antibacterial properties, fabricated using the linear sputtering method. The linear sputtering technique deposits thin films onto continuous substrates, offering high throughput, uniform coatings, and precise control over film properties. In this research, Cu/AZO thin films underwent either vacuum annealing or hydrogen plasma annealing treatments. The Cu layer imparts antibacterial properties, while the AZO layer primarily provides thermal insulation. Experimental results show that annealing treatments enhance both photoelectric performance and antibacterial capability. Annealed Cu/AZO films exhibit lower resistivity and emissivity. Among the samples, those subjected to vacuum annealing at 400 °C are most suitable for low-emissivity applications, with an average visible light transmittance of 60%, an emissivity of 0.16, and an antibacterial activity value of 8.8. The Cu/AZO films proposed in this study effectively combine antibacterial and thermal insulation properties, making them relevant for the field of green materials. Full article

ZnO film ultrasonic transducers for temperature and stress measurements with dual-mode wave excitation (longitudinal and shear) were deposited using the reactive RF magnetron sputtering technique on Si and stainless steel substrates and construction steel bolts. It was found that the position in the substrate plane had a significant effect on the structure and ultrasonic performance of the transducers. The transducers deposited at the center of the deposition zone demonstrated a straight columnar structure with a c-axis parallel to the substrate normal and the generation of longitudinal waves. The transducers deposited at the edge of the deposition zone demonstrated inclined columnar structures and the generation of dominant shear or longitudinal shear waves. Transducers deposited on the bolts with dual-wave excitation were used to study the effects of high temperatures in the range from 25 to 525 °C and tensile stress in the range from 0 to 268 MPa on ultrasonic response. Dependencies between changes in the relative time of flight and temperature or axial stress were obtained. The dependencies can be described by second-order functions of temperature and stress. An analysis of the contributions of thermal expansion, strain, and the speed of sound to changes in the time of flight was performed. At high temperatures, a decrease in the signal amplitude was observed due to the decreasing resistivity of the transducer. The ZnO ultrasonic transducers can be used up to temperatures of ~500 °C. Full article

To solve the problems on resource utilization and environmental pollution of waste concrete and waste polypropylene (PP) plastics, the recycling of them into asphalt pavement is a feasible approach. Considering the high melting temperature of waste PP, this study adopted a thermal-and-mechanochemical method to convert waste PP into high-performance warm-mix asphalt modifiers (PPMs) through the hybrid use of dicumyl peroxide (DCP), maleic anhydride (MAH), and epoxidized soybean oil (ESO) for preparing an asphalt mixture (RCAAM) containing recycled concrete aggregate (RCA). For the prepared RCAAM containing PPMs, the mixing temperature was about 30 °C lower than that of the hot-mix RCAAM containing untreated PP. Further, the high-temperature property, low-temperature crack resistance, moisture-induced damage resistance, and fatigue resistance of the RCAAM were characterized. The results indicated that the maximum flexural strain of the RCAAM increased by 7.8~21.4% after using PPMs, while the sectional fractures of the asphalt binder were reduced after damaging at low temperature. The use of ESO in PPMs can promote the cohesion enhancement of the asphalt binder and also improve the high-temperature deformation resistance and fatigue performance of the RCAAM. Notably, the warm-mix epoxidized PPMA mixture worked better close to the hot-mix untreated PPMA mixture, even after the mixing temperature was reduced by 30 °C. Full article