Crosslinked polymers' excellent performance and broad engineering uses have significantly impacted the development of advanced polymer slurries for use in pipe jacking methods. This study presented a groundbreaking methodology, incorporating boric acid crosslinked polymers into polyacrylamide bentonite slurry, addressing the deficiencies of conventional grouting materials while fulfilling essential working performance expectations. The slurry's funnel viscosity, filter loss, water dissociation ratio, and dynamic shear properties were evaluated using an orthogonal experimental design. check details To identify the optimal mix proportion, a single-factor range analysis, structured by an orthogonal design, was carried out. X-ray diffraction and scanning electron microscopy were used to evaluate the characteristics of mineral crystal formation and the microstructure, respectively. Through a cross-linking reaction, guar gum and borax, as per the results, generate a dense cross-linked boric acid polymer. The crosslinked polymer concentration's increase led to a more continuous and tighter internal structure. The effectiveness of the anti-permeability plugging action and viscosity of slurries was remarkably enhanced, escalating by 361% to 943%. The precise optimal proportions for sodium bentonite, guar gum, polyacrylamide, borax, and water are 10%, 0.2%, 0.25%, 0.1%, and 89.45%, respectively. These undertakings highlighted the viability of enhancing slurry composition through the utilization of boric acid crosslinked polymers.
For the remediation of textile dyeing and finishing wastewater containing dye molecules and ammonium, the in situ electrochemical oxidation method is receiving considerable attention. Nevertheless, the economic outlay and longevity of the catalytic anode have significantly circumscribed industrial applications of this process. This work details the fabrication of a novel lead dioxide/polyvinylidene fluoride/carbon cloth composite (PbO2/PVDF/CC) through the integration of surface coating and electrodeposition processes, leveraging a lab-based waste polyvinylidene fluoride membrane. Operational parameters, encompassing pH, chloride concentration, current density, and initial pollutant concentration, were scrutinized to determine their influence on the oxidation efficacy of the PbO2/PVDF/CC system. In a favorable environment, this composite material demonstrates 100% decolorization of methyl orange (MO), a 99.48% removal of ammonium ions, a 94.46% transformation of ammonium-based nitrogen into N2, and a remarkable 82.55% decrease in chemical oxygen demand (COD). In the context of coexisting ammonium and MO, MO decolorization, ammonium removal, and COD reduction maintain exceptionally high rates, roughly 100%, 99.43%, and 77.33%, respectively. Hydroxyl radical and chloride species synergistically oxidize MO, while chlorine oxidizes ammonium, exhibiting a combined effect. Through the identification of numerous intermediate substances, MO is finally mineralized to CO2 and H2O, and ammonium is primarily converted to N2. Regarding stability and safety, the PbO2/PVDF/CC composite performs extremely well.
Particulate matter, 0.3 meters in size, is readily inhaled and presents considerable threats to human health. High-voltage corona charging, essential for treating traditional meltblown nonwovens in air filtration, unfortunately exhibits the problem of electrostatic dissipation, reducing filtration efficacy. The process of constructing a composite air filter with remarkable efficiency and low resistance in this study involved the alternating lamination of ultrathin electrospun nano-layers and melt-blown layers, without resorting to corona charging methods. To determine the impact of fiber diameter, pore size, porosity, layer count, and weight on filtration performance, an experimental study was conducted. check details Simultaneously, the study explored the surface hydrophobicity, loading capacity, and long-term storage stability of the composite filter. Laminated fiber-webs (185 gsm), composed of 10 layers, demonstrate exceptional filtration efficiency (97.94%), a low pressure drop (532 Pa), a high quality factor (QF 0.0073 Pa⁻¹), and a substantial dust holding capacity (972 g/m²) for NaCl aerosol particles. By increasing the number of layers and diminishing the weight of each layer, a substantial advancement in filtration performance and a decrease in pressure drop are attainable. Following an 80-day storage period, the filtration efficiency exhibited a modest decline, moving from 97.94% to 96.48%. A composite filter, constructed from alternating ultra-thin nano and melt-blown layers, exhibited a layer-by-layer interception and collaborative filtering effect. High filtration efficiency and low resistance were achieved without the need for high voltage corona charging. The application of nonwoven fabrics in air filtration gained new perspectives thanks to these findings.
For a wide array of phase change materials, the strength properties of materials, which decline by no greater than twenty percent after thirty years of use, warrant special consideration. One recurring aspect of PCM climatic aging is the generation of mechanical parameter gradients within the plate's thickness. When simulating PCM strength over extended operational times, gradients must be factored in. Currently, global scientific understanding lacks a reliable foundation for accurately forecasting the physical and mechanical properties of phase change materials (PCMs) over extended operational durations. Nevertheless, the qualification of PCMs under varying climate conditions has been a globally accepted approach to validating their reliable operation in many mechanical engineering sectors. This review examines the effects of solar radiation, temperature, and moisture on the mechanical properties of PCMs, as measured by dynamic mechanical analysis, linear dilatometry, profilometry, acoustic emission, and other techniques, considering variations across the material thickness. Moreover, the mechanisms of uneven climatic degradation in PCMs are elucidated. check details Ultimately, the challenges associated with theoretically modeling the uneven climatic aging of composite materials are highlighted.
The objective of this study was to evaluate the efficiency of functionalized bionanocompounds incorporating ice nucleation protein (INP) for freezing applications, measuring the energy consumption at each stage of freezing when water bionanocompound solutions are compared with pure water. A manufacturing analysis shows that water demands 28 times less energy than the silica + INA bionanocompound, and 14 times less than the magnetite + INA bionanocompound mixture. The manufacturing process's energy footprint for water was significantly smaller than other materials. To assess the environmental consequences, a study of the operational phase was performed, factoring in the defrosting duration for each bionanocompound within a four-hour work cycle. Our study highlights the potential of bionanocompounds to substantially lessen environmental repercussions, achieving a 91% reduction in impact during each of the four operational work cycles. Significantly, the demands of energy and raw materials within this process caused this advancement to be more impactful than its effect on the manufacturing stage. Analysis of the results from both stages indicated that the magnetite + INA bionanocompound and the silica + INA bionanocompound displayed an estimated 7% and 47% reduction in total energy consumption, respectively, when measured against water. The study's results illustrated a strong potential for bionanocompounds in applications involving freezing, thereby minimizing their adverse effects on both the environment and human health.
Transparent epoxy nanocomposites were produced from two nanomicas, sharing a muscovite and quartz base, but exhibiting disparate particle size distributions. Unmodified, the nano-sized particles exhibited a homogeneous dispersion, preventing aggregation and consequently maximizing the interfacial contact area between the nanofiller and the matrix. Although the filler was dispersed extensively within the matrix, resulting in nanocomposites exhibiting less than a 10% reduction in visible light transparency at both 1% wt and 3% wt mica filler concentrations, XRD analysis showed no signs of exfoliation or intercalation. Despite the presence of micas, the thermal performance of the nanocomposites remains unchanged, maintaining the characteristics of the neat epoxy resin. Regarding epoxy resin composites, the mechanical characterization revealed a noticeable enhancement in Young's modulus, accompanied by a decrease in tensile strength. A peridynamics-driven approach utilizing a representative volume element was implemented to determine the effective Young's modulus of the nanomodified materials. Through a classical continuum mechanics-peridynamics coupling, the analysis of the nanocomposite fracture toughness was informed by the results derived from this homogenization procedure. The peridynamics methods' ability to correctly represent the effective Young's modulus and fracture toughness of epoxy-resin nanocomposites is substantiated by the correspondence with experimental data. Eventually, the new mica-based composite materials display high volume resistivity, making them premier insulating candidates.
Ionic liquid functionalized imogolite nanotubes (INTs-PF6-ILs) were introduced into the epoxy resin (EP)/ammonium polyphosphate (APP) system to scrutinize its flame retardancy and thermal characteristics using the limiting oxygen index (LOI) test, the UL-94 test, and the cone calorimeter test (CCT). INTs-PF6-ILs and APP exhibited a synergistic effect, as indicated by the results, impacting the char formation and anti-dripping characteristics of EP composites. The 4 wt% APP loading of the EP/APP resulted in a UL-94 V-1 rating. In contrast to expectations, the composites containing 37% APP and 0.3% INTs-PF6-ILs passed the UL-94 V-0 rating without exhibiting any dripping. A marked decrease of 114% and 211% was observed in the fire performance index (FPI) and fire spread index (FSI), respectively, for the EP/APP/INTs-PF6-ILs composite in comparison to the EP/APP composite.