Engineering practices frequently utilize crosslinked polymers, showcasing their remarkable performance and driving the development of novel polymer slurries for pipe jacking applications. This study's innovative solution involves the utilization of boric acid crosslinked polymers mixed within a polyacrylamide bentonite slurry, effectively overcoming limitations of traditional grouting materials and aligning with required general performance parameters. Measurements of funnel viscosity, filter loss, water dissociation ratio, and dynamic shear of the new slurry were taken using an orthogonal experimental design. read more To determine the ideal mixture ratio, a single-factor range analysis, employing an orthogonal design, was performed. Subsequently, X-ray diffraction and scanning electron microscopy were utilized to assess the formation patterns of mineral crystals and the microstructure, respectively. Guar gum and borax, as evidenced by the results, yield a dense cross-linked boric acid polymer through a cross-linking reaction. The increasing concentration of crosslinked polymer resulted in a more tightly bound and unbroken internal structure. The effectiveness of the anti-permeability plugging action and viscosity of slurries was remarkably enhanced, escalating by 361% to 943%. Sodium bentonite, guar gum, polyacrylamide, borax, and water were combined in optimal proportions of 10%, 0.2%, 0.25%, 0.1%, and 89.45%, respectively. The application of boric acid crosslinked polymers to slurry composition improvement was shown by these works to be possible.
Textile dyeing and finishing wastewater treatment has seen a rise in the use of in-situ electrochemical oxidation, a process receiving considerable attention for the elimination of dye and ammonium molecules. Although, the price and durability of the catalytic anode have greatly curtailed the implementation of this technique in industrial applications. A lead dioxide/polyvinylidene fluoride/carbon cloth composite (PbO2/PVDF/CC) was synthesized in this work using a lab-based waste polyvinylidene fluoride membrane, achieved through the integrated application of surface coating and electrodeposition processes. A study was conducted to determine how the operating parameters—pH, chloride concentration, current density, and initial pollutant concentration—impact the oxidation efficiency of the PbO2/PVDF/CC system. Under optimum conditions, this composite material completely decolorizes methyl orange (MO), removing 99.48% of ammonium and converting 94.46% of ammonium-based nitrogen to N2, as well as achieving an 82.55% reduction in chemical oxygen demand (COD). Coexistence of ammonium and MO leads to sustained levels of MO decolorization, ammonium removal, and chemical oxygen demand (COD) reduction at near-maximal levels, approximately 100%, 99.43%, and 77.33%, respectively. A combination of hydroxyl radical and chloride-mediated oxidation synergistically affects MO, whereas ammonium undergoes oxidation by chlorine. MO is eventually mineralized to CO2 and H2O, a result of the identification of numerous intermediates, and ammonium is principally transformed into N2. The PbO2/PVDF/CC composite's performance is marked by exceptional stability and safety.
Particulate matter particles, 0.3 meters in diameter, are inhalable and pose substantial threats to human well-being. In the air filtration process, traditional meltblown nonwovens require high-voltage corona charging. However, this process's vulnerability to electrostatic dissipation negatively impacts filtration efficiency. Through the meticulous alternation of ultrathin electrospun nano-layer and melt-blown layer laminations, a highly efficient and low-resistance composite air filter was fabricated in this work without employing corona charging. A comprehensive investigation was conducted to analyze the relationship between fiber diameter, pore size, porosity, the number of layers, and weight, with regards to filtration performance. read more A study was performed to determine the composite filter's properties, including surface hydrophobicity, loading capacity, and storage stability. 10-ply 185-gsm laminated fiber-webs demonstrate a noteworthy filtration efficiency (97.94%), low pressure drop (532 Pa), a high quality factor (QF 0.0073 Pa⁻¹), and a remarkable capacity to retain NaCl aerosol particles (972 g/m²). Augmenting the number of layers while diminishing the weight of each layer can substantially enhance filtration efficacy and lessen the pressure decline across the filter. Following an 80-day storage period, the filtration efficiency exhibited a modest decline, moving from 97.94% to 96.48%. Alternating ultra-thin nano and melt-blown layers within the composite filter produced a layered, collaborative filtering and interception mechanism. This yielded high filtration efficiency and low resistance, eliminating the requirement for high voltage corona charging. The study of nonwoven fabrics in air filtration has progressed substantially due to the new understanding provided by these results.
With regard to a diverse assortment of PCMs, the strength attributes of materials showing a reduction of not more than 20% after thirty years of operation are of considerable importance. A recurring characteristic of PCM climatic aging is the development of mechanical property variations as a function of the plate's thickness. Long-term PCM strength predictions hinge on the acknowledgment of gradient occurrences within the modeling process. The scientific community currently lacks a basis for the dependable forecasting of the physical and mechanical traits of phase change materials over extended periods of operation. Undeniably, the assessment of PCMs against various climatic factors has been a standardized and globally recognized procedure for guaranteeing their secure performance in a multitude of mechanical engineering fields. This review scrutinizes the impact of solar radiation, temperature, and moisture variations on PCM mechanical properties, considering the thickness gradients, utilizing dynamic mechanical analysis, linear dilatometry, profilometry, acoustic emission, and other measurement approaches. Besides, the methods by which PCMs experience uneven climatic aging are detailed. read more The theoretical modeling of composites' variable deterioration due to uneven climates is, finally, analyzed for its limitations.
To evaluate the effectiveness of a novel approach to freezing using functionalized bionanocompounds with ice nucleation protein (INP), this study measured the energy consumption at each step of the freezing process, contrasting water bionanocompound solutions with pure water samples. The results of the manufacturing analysis suggest that water requires 28 times less energy than the silica + INA bionanocompound, while also demonstrating 14 times lower energy requirements compared to the magnetite + INA bionanocompound. 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. Bionanocompounds demonstrably reduced environmental impact by 91% after implementation during all four work cycles of the operation phase, as our research revealed. Subsequently, the demands for energy and raw materials in this process elevated the impact of this enhancement relative to its significance during the manufacturing stage. The findings from both stages suggest that using the magnetite + INA bionanocompound and the silica + INA bionanocompound would save an estimated 7% and 47% in total energy consumption, respectively, compared to water. The study's results underscored a considerable potential for bionanocompounds in freezing applications, aiming to lessen their environmental and health repercussions.
Two nanomicas, containing both muscovite and quartz, but differing in their particle size distribution, were used for the production of transparent epoxy nanocomposites. Despite the absence of organic modification, the nano-sized particles exhibited a uniform dispersion, avoiding any aggregation and thereby optimizing the matrix-nanofiller interfacial contact. The presence of 1% wt and 3% wt mica fillers, while effectively dispersing within the matrix to produce nanocomposites with a visible light transparency reduction of less than 10%, failed to induce any exfoliation or intercalation, as observed via XRD. The thermal properties of the nanocomposites, exhibiting consistency with that of the plain epoxy resin, are unaffected by the presence of mica fillers. Analysis of epoxy resin composites' mechanical properties demonstrated a rise in Young's modulus, but a concomitant drop in tensile strength. An approach using peridynamics and a representative volume element was used to estimate the effective Young's modulus in nanomodified materials. Analysis of the nanocomposite's fracture toughness, using a coupled continuum mechanics-peridynamics approach, leveraged the results of this homogenization process. A comparison of the peridynamics-based predictions with experimental data reveals the strategies' ability to model the effective Young's modulus and fracture toughness of epoxy-resin nanocomposites precisely. Ultimately, the novel mica-based composites demonstrate elevated volume resistivity, thereby positioning them as superior insulating materials.
Ionic liquid-functionalized imogolite nanotubes (INTs-PF6-ILs) were mixed with epoxy resin (EP)/ammonium polyphosphate (APP) to study their flame retardancy and thermal stability; these properties were characterized using the limiting oxygen index (LOI) test, the UL-94 test, and the cone calorimeter test (CCT). The research findings suggest a combined effect of INTs-PF6-ILs and APP on the char formation process and anti-dripping performance 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. Furthermore, the fire performance index (FPI) and fire spread index (FSI) of EP/APP/INTs-PF6-ILs composites exhibited a significant decrease of 114% and 211%, respectively, when contrasted with the EP/APP composite.