Search Results (28,134)

A novel flow process to produce low-molecular-weight (Mwt) methacrylate oligomer mixtures that have potential as vaccine adjuvants and chain transfer agents (CTAs) is reported. The chemistry and process were designed to significantly reduce the number of stages required to manufacture methyl methacrylate oligomer-in-monomer mixtures with an oligomer Mwt range of dimers to pentamers and >50% conversion. Combining rapid in-flow, in situ catalytic chain transfer polymerization catalyst synthesis and volumetric microwave heating of the reaction medium resulted in catalyst flow synthesis being completed in <4 min, removing the need to pre-synthesize it. The steady-state operation was then successfully maintained with very low levels of external energy, as the process utilized the reaction exotherm. The microwave process outperformed a comparative conventionally heated system by delivering a 20% increase in process throughput with no change in final product quality or conversion. Additionally, combining flow and in situ catalyst processing enabled the use of a more oxidatively unstable catalyst. This allowed for in situ catalyst deactivation post-generation of the oligomers, such that residual catalyst did not need to be removed prior to preparing subsequent vaccine adjuvant or CTA screening formulations. Finally, dielectric property measurements were able to monitor the onset of reaction and steady-state operation. Full article

Accurate Remaining Useful Life (RUL) prediction is vital for effective prognostics in and the health management of industrial equipment, particularly under varying operational conditions. Existing approaches to multi-condition RUL prediction often treat each working condition independently, failing to effectively exploit cross-condition knowledge. To address this limitation, this paper introduces MoEFormer, a novel framework that combines a Mixture of Encoders (MoE) with a Transformer-based architecture to achieve precise multi-condition RUL prediction. The core innovation lies in the MoE architecture, where each encoder is designed to specialize in feature extraction for a specific operational condition. These features are then dynamically integrated through a gated mixture module, enabling the model to effectively leverage cross-condition knowledge. A Transformer layer is subsequently employed to capture temporal dependencies within the input sequence, followed by a fully connected layer to produce the final prediction. Additionally, we provide a theoretical performance guarantee for MoEFormer by deriving a lower bound for its error rate. Extensive experiments on the widely used C-MAPSS dataset demonstrate that MoEFormer outperforms several state-of-the-art methods for multi-condition RUL prediction. Full article

High-entropy materials, characterized by complex chemical compositions, are difficult to identify and describe structurally. These problems are encountered at the composition design stage when choosing an effective method for predicting the final phase structure of the alloy, which affects its functional properties. In this work, the effects of introducing oxide precipitates into the matrix of a high-entropy TiCoCrFeMn alloy to strengthen ceramic particles were studied. The particles were introduced by the ex situ method, such as TiO₂ in the form of anatase, and by the in situ method, consisting of the reconstruction of CuO into TiO₂. In both cases, it was assumed that after the homogenization process, carried out at 1000 °C, ceramic precipitates in the rutile phase, commonly considered a stable allotropic form of TiO₂, would be obtained. However, the microscopic observations and XRD analyses, supported by EDS chemical composition microanalysis and EBSD backscattered electron diffraction, clearly revealed that, regardless of the method of introducing oxides, the final strengthening phase obtained was a mixture of TiO₂ in the form of anatase with the Magnelli phase of Ti₂O₃. In this work, phase reconstruction in the Ti-O system was analyzed using changes in the Gibbs free energy of the identified oxide phases. Full article

Chinese herbal medicines have become a new green feed additive in the aquaculture industry. The aim of this study is to investigate the effects of traditional Chinese herbal medicines (Isatidis radix, Forsythia suspensa, and Schisandra chinensis) on the growth performance, antioxidant capacity, and intestinal microbiota of hybrid snakehead (Channa maculata ♀ × Channa argus ♂). A total of 600 fish (mean weight: 15.85 ± 0.15 g) were randomly assigned to five groups, including the control group (CG), I. radix extract group (IRE), F. suspensa extract group (FSE), S. chinensis extract group (SCE), and the Chinese herbal medicine mixture group (CHMM; a mixture of extracts of I. radix, F. suspensa, and S. chinensis at the ratio of 1:1:1) for 6 weeks. The results show that the IRE-supplemented diet improved the survival rate (SR), feed efficiency ratio (FE), and condition factor (CF) compared to others. Compared to the control group, the activity of superoxide dismutase (SOD) in plasma and intestine was significantly increased in the FSE and CHMM groups, whereas the content of malondialdehyde (MDA) in plasma and liver was significantly reduced in the SCE group. A 16s rRNA analysis indicates that dietary supplementation with FSE significantly promoted the proliferation of Fusobacteriota, while IRE supplementation increased the alpha diversity of intestinal bacteria. In conclusion, the addition of I. radix to the diet of hybrid snakehead improves growth, antioxidant capacity, and liver and intestine health, and modulates the intestinal microbiota of snakehead positively. Full article

Fault fracture zones, characterized by high weathering, low strength, and a high degree of fragmentation, are common adverse geological phenomena encountered in tunneling projects. This paper performed a series of large-scale triaxial compression tests on the cohesive soil–rock mixture (SRM) samples with dimensions of 500 mm × 1000 mm to investigate the influence of rock content P_BV (20, 40, and 60% by volume), rock orientation angle α, and confining pressure on their macro-mechanical properties. Furthermore, a triaxial numerical model, which takes into account P_BV and α, was constructed by means of PFC^3D to investigate the evolution of the mechanical properties of the cohesive SRM. The results indicated that (1) the influence of the α is significant at high confining pressures. For the sample with an α of 0°, shear failure was inhibited, and the rock blocks tended to break more easily, while the samples with an α of 30° and 60° exhibited fewer fragmentations. (2) P_BV significantly affected the shear behaviors of the cohesive SRM. The peak deviatoric stress of the sample with an α of 0° was minimized at lower P_BV (<20%), while both the deformation modulus and peak deviatoric stress were larger at high P_BV (>60%). Based on these findings, an equation correlating shear strength and P_BV was proposed under consistent α and matrix strength conditions. This equation effectively predicts the shear strength of the cohesive SRM with different P_BV values. Full article

Zeolitic imidazolate framework-8 (ZIF-8) has been extensively studied as a precursor for nitrogen-doped carbon (NC) materials due to its high surface area, tunable porosity, and adjustable nitrogen content. However, the intrinsic microporous structure of the ZIF-8 limits mass transport and accessibility of reactants to active sites, reducing its effectiveness in electrochemical applications. In this study, a soft templating approach using a triblock copolymer was used to prepare mesoporous ZIF-8-derived NC (Meso-ZIF-NC) samples. The hierarchical porous structure was investigated by varying the ratios of Pluronic F-127, NaClO₄, and toluene. The resulting Meso-ZIF-NC exhibited widespread pore size distribution with an enhanced mesopore (2–50 nm) volume according to the composition of the reaction mixtures. Pt nanoparticles were uniformly dispersed on the Meso-ZIF-NC to form Pt/Meso-ZIF-NC catalysts, which presented a high electrochemical surface area and improved oxygen reduction reaction activity. The study highlights the important role of mesopore structure and nitrogen doping in enhancing catalytic performance, providing a pathway for advanced fuel cell catalyst design. Full article

In this study, the usability of construction and demolition waste (CDW) aggregates as filling when stabilized with alkaline activator solution (AAS) and blast furnace slag (BFS) was investigated. The initial stage of this study involved determining the engineering properties of CDW by laboratory experiments. In the next stage, modified Proctor tests were performed to investigate the compaction behavior of CDW, to which 5% to 30% BFS was added with water or AAS. In the following stage, California bearing ratio experiments were performed to determine the mixture specimen with the highest strength. In the final stage, a weak soil layer was created in a test tank, and fillings of different thicknesses were built on it using CDW with and without additives in the determined optimum mixing ratio. Then, plate-loading tests were conducted using a model foundation to evaluate the load–deformation behavior of the fillings. The study’s results indicated that adding BFS with water or AAS to CDW increased strength. Furthermore, the addition of 20% BFS yielded the highest strength value, and the CDW aggregates with the added BFS increased the ultimate bearing capacity by up to 4.72 times compared to those without the additive. Full article

In the last 10–15 years, the use of waste refractory materials has significantly increased because it is not economically justified to transport such expensive materials to landfills. This work compared the physical and mechanical properties of refractory concrete samples with those of individual deflocculants—polycarboxilate, sodium tripolyphosphate, and a deflocculant mixture. Three refractory concrete compositions with individual deflocculants and a deflocculant mix were created to choose the best main properties of refractory concrete. Five compositions of refractory concrete specimens were created by partial replacement of chamotte aggregate (CA) by refractory concrete waste (RCW) (100, 75, 50, and 25%). Exothermal profile, structure development and spread were determined for fresh refractory concrete pastes. It was found that with an increase in CA replacement level to RCW, the EXO maximum temperature, spread and structure evolution speed decreases. SEM and porosity tests confirmed density, compressive strength results and structural parameters. The study shows that RCW replacement slows the hydration process, particularly at replacement levels above 33%. However, replacement levels of up to 25% improve compressive strength by 13% due to the additional amount of cement minerals in RCW aggregates, which can participate in the hydration process, making it a viable option for applications where enhanced durability is required, such as in non-critical zones of industrial refractory linings. Full article

This study explores the optimization of hydrometallurgical processes for recycling lithium-ion batteries (LIBs) containing a mixture of lithium iron phosphate (LFP) and nickel–manganese–cobalt (NMC) cathodes. Two approaches were investigated: acid-excess leaching and acid-deficient leaching with residue recirculation. A design of experiments (DoE) framework was applied to assess the impact of key parameters, including sulfuric acid and hydrogen peroxide concentrations, as well as solid-to-liquid (S/L) ratios, on the dissolution yields of target metals (Ni, Mn, Co, and Li). Acid-excess leaching achieved nearly complete dissolution of target metals but required additional purification steps to remove impurities. Acid-deficient leaching with a 60% recirculation of leaching residue improved dissolution yields by up to 12.5%, reduced reagent consumption, and minimized operational complexity. The study also evaluated separation strategies for manganese and cobalt through solvent extraction. Results indicate that while acid-excess leaching offers higher yields, acid-deficient leaching with residue recirculation is more cost-effective and environmentally friendly. These findings provide valuable insights for developing sustainable LIB recycling technologies. Full article

Ensuring the mechanical performance of backfill materials while reducing cementation costs is a key challenge in mine backfill research. To address this, fiber materials such as polypropylene (PP) fiber and rice straw (RS) fiber have been incorporated into cement-based mixtures for mine backfilling. This study investigates the effects of PP and RS fibers on the mechanical properties, flow characteristics, and microstructure of Tailings and Wasted Stone Mixed Backfill (TWSMB). A series of orthogonal experiments were designed to evaluate the influence of variables, including the cement–sand ratio, solid mass concentration, wasted stone mass concentration, fiber content, and fiber length on the TWSMB properties. The results indicate that the influence of cement–sand ratio and solid mass concentration have a more significant impact on strength than fibers, though the fibers show a stronger effect than the wasted stone mass concentration. Both fiber types enhanced the strength of the specimens, with PP fiber exhibiting a stronger reinforcing effect than RS fiber. Furthermore, the effect of PP fiber content was more pronounced than that of fiber length, whereas the opposite trend was observed for RS fiber. The optimum fiber parameter levels were determined for each type: PP fiber performed best at a mass concentration of 1.5% and a length of 6 mm, while RS fiber showed optimal performance at a mass concentration of 1.0% and a length of 5–10 mm. Macroscopic damage analysis indicated that the structural integrity and residual compressive strength of the TWSMB specimens were preserved even after surpassing the ultimate compressive strength, due to the crack-bridging effect of the fibers. Microstructural analysis showed that PP fiber-reinforced specimens exhibited a dense structure formed through reactions with other hydration products. In contrast, the surface of RS fibers was nearly fully encapsulated by hydration products, resulting in the formation of a physical skeleton structure. This study provides new insights into minimizing cement consumption and reducing backfilling costs in mining operations. Full article

Environmentally persistent free radicals (EPFRs) are a new class of pollutants that have been identified as potential environmental contaminants due to their persistence and ability to generate reactive oxygen species (ROS) that cause oxidative stress in living organisms. This study investigates the formation and behavior of EPFRs during the photodegradation of organic pollutants, emphasizing the role of metal ions, precursor concentration, and environmental conditions. Results show that light exposure significantly enhances pollutant degradation rates, EPFR yield, and formation speed, though it simultaneously shortens EPFR lifespan due to reactive oxygen species (ROS) generation. In dark conditions, EPFR formation is slower but results in more stable radicals. Metal ions play a pivotal role, with Cu(II) exhibiting the highest EPFR generation capacity due to its strong electron-accepting properties, surpassing Zn(II) and Na(I), highlighting that metal ions with greater oxidizing potential enhance EPFR formation. The precursor, as both reaction product and reactant, plays a dual role in EPFR formation. Individual compounds like anthracene (ANT) yield stable carbon-centered radicals, while mixtures of polycyclic aromatic hydrocarbons (PAHs) produce more complex radical spectra. The study of the influencing factors and transformation mechanisms of EPFR generation in soil can provide a more comprehensive understanding of the environmental behavior of new pollutants, provide a scientific basis for sustainable development, and be of great significance for the assessment and management of environmental risks and the protection of the ecological environment. Full article

Complex mixtures of air pollutants, including ozone (O₃), carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), black carbon (BC), and fine particulate matter (PM_2.5), present significant health risks. To understand the factors influencing air pollution levels and their temporal variations, comprehensive high-resolution long-term air pollution data are essential. This study analyzed the characteristics, lagged meteorological effects, and temporal patterns of six air pollutant concentrations over a one-year period at an urban residential site in Kenitra, Morocco. The results reveal pronounced seasonal and diurnal variations in pollutant levels, shaped by meteorological factors, emission sources, and local geographic conditions. PM_2.5, SO₂, and CO concentrations peaked during winter, while NO₂ and CO exhibited consistent diurnal peaks during morning and evening rush hours across all seasons, driven by traffic emissions and nocturnal pollutant accumulation. In contrast, O₃ concentrations were highest during summer afternoons due to photochemical reactions fueled by strong UV radiation, while winter levels were the lowest due to reduced sunlight. Lagged meteorological effects further highlighted the complexity of air pollutant dynamics. Meteorological factors, including temperature, wind speed, humidity, and pressure, significantly influenced pollutant levels, with both immediate and lagged effects observed. Lag analyses revealed that PM_2.5 and BC levels responded to wind speed, temperature, and humidity over time, highlighting the temporal dynamics of dispersion and accumulation. CO is sensitive to temperature and pressure changes, with delayed impacts, while O₃ formation was primarily influenced by temperature and wind speed, reflecting complex photochemical processes. SO₂ concentrations were shaped by both immediate and lagged meteorological effects, with wind direction playing a key role in pollutant transport. These findings emphasize the importance of considering both immediate and lagged meteorological effects, as well as seasonal and diurnal variations, in developing air quality management strategies. Full article

To thoroughly study the stress–strain relationship of lightweight mixed ceramic concrete, this paper conducts axial compressive strength tests on three groups of lightweight mixed ceramic concrete specimens with different types and contents as the basis. It establishes the elastic modulus calculation formula and compressive stress–strain formula for lightweight mixed ceramic concrete by combining with the current standards and related research. The results show that lightweight mixed ceramic concrete, made of a mixture of different types and densities of ceramic grains, has better mechanical properties and deformation properties. The calculation errors of the modulus of elasticity formulas, derived from the experimental results for the three groups of lightweight mixed ceramic concretes, are all controlled within 5%. The average relative errors of the fitting results of stress–strain curves for the three groups of specimens and the measured data are as low as 6.66%, 3.16%, and 3.39%. The errors between the experimental values of the modulus of elasticity of different studies and the predicted values based on the formula in this paper were controlled within 17%, and the average relative errors between the predicted and experimental results of the stress–strain curves for the three groups of specimens were 2.64%, 8.94%, and 17.50%. This paper innovatively constructs a prediction model of key mechanical parameters of lightweight mixed ceramic concrete, which can provide a reference and experimental basis for the structural analysis and application of lightweight mixed ceramic concrete. Full article

In this paper, a method of ultrasound-assisted low-pressure closed acid digestion followed by inductively coupled plasma mass spectrometry (ICP-MS) analysis was proposed for trace element quantification in rock samples. By using 1.5 mL of a binary acid mixture of HNO₃–HF with a ratio of 2:1, rock powder samples of 50 mg were completely decomposed in 12 h at 140 °C after 4 h of ultrasonic treatment with or without pressure relief procedure. The element extraction efficiency of this method was evaluated via the yielded relative errors (REs) of the trace elements in a series of geological standard reference materials (SRMs) with compositions from basic to acidic. It was found that the contents of trace elements (i.e., 36 metal elements from Li to U) in basalt BCR-2, diabase W-2a, andesite AGV-2, granodiorite GSP-2, and granite GSR-1 were comparable with the reported reference values, giving REs with absolute values less than 10%. It was also found that clear solutions without sample powder residues by naked-eye observation can be obtained when using the low-pressure closed decomposition method without ultrasonic pretreatment. The quantification results, however, were found to be negatively biased for most of the studied trace elements, and, in particular, the content bias of Zr in SRM GSP-2 was down to −86.28% due to the low extraction efficiency of refractory minerals of the low-pressure closed digestion method. By applying this proposed digestion strategy, the decomposition property of the ternary combination of HNO₃–HF–mannitol in terms of trace element quantification accuracy was also investigated. Results showed that the concentrations of trace elements in the studied SRMs were consistent with the reference values, giving REs within ±6.94%, which revealed that there was no deterioration of extraction efficiencies of trace elements and neglected mass interferences from mannitol. This study demonstrated the essential role of ultrasound irradiation in rock sample decomposition to achieve the high extraction efficiency of trace elements under a low-pressure environment, and the developed approach with promising future applications in geoscience exhibited considerable merits, including a high extraction efficiency, feasible digestion process, less time consumption, and lower safety associated risks. Full article

Technical and economic criteria were used to evaluate the feasibility of the treatment of an industrial effluent (10 m³/h) for water recovery and reuse. The treatment evaluation included the following: (1) effluent characteristic determination; (2) selection and evaluation of the effluent treatment at lab scale, establishing operating conditions and process efficiency; (3) scaling up the treatment process to the industrial level; (4) treatment plant design and commercial availability analysis of the required equipment; and (5) the costs of the inversion and operation of the plant treatment, cost/m³ for water recovery, and time of investment recovery. The physicochemical characteristics of the effluent exposed the polluted wastewater with sodium chloride salts and colourants, predominating a mixture of tartrazine, Red 40, and brilliant blue from the synthesis of food additives. Other contributions of organic compounds and salts could be in minor content. According to the effluent conditions, a coupled process, integrated with ozonation and reverse osmosis, was indicated to be a treatment for water recovery. Scaling up the plant treatment design resulted in 130 m² of area, producing 7.7 m³/h of clean water. The cost of the effluent treatment was 1.4 USD/m³, with an inversion return of 3.4 years and cost investment of USD 860,407. The treatment process resulted a viable project for water recovery. Full article