Search Results (1,580)

The performance of oil–water coalescence separation elements currently fails to meet the increasing demands of the oily wastewater treatment industry. To address this challenge, a series of fiber coalescing filters were developed through an underwater superoleophobic modification process using a simple impregnation technique. The effect of varying surface wettability on the separation efficiency of oil-in-water (O/W) emulsions stabilized with surfactants was investigated. The results demonstrate that, after undergoing underwater superoleophobic modification, the separation efficiency of the fiber filter material improved by 33.9%, the pressure drop was reduced by 46.1%, and the steady-state quality factor increased by 83.3%. Building upon these findings, an oil-repellent pore size gradient structure was introduced for the coalescence separation of surfactant-stabilized oil-in-water emulsions. This structure exhibited outstanding characteristics, including a low pressure drop and a high-quality factor. Furthermore, when processing emulsions stabilized with surfactants such as OP-10 (nonionic), CTAB (cationic), and SDS (anionic), the structure maintained high separation efficiencies of 93.6%, 96.4%, and 97.2%, respectively, after 10 cycles. Finally, based on experimental data and theoretical analysis, a separation mechanism for oil–water coalescence using superoleophobic pore size gradient filtration materials is proposed. This structure demonstrates significant potential for widespread application in liquid–liquid separation technologies. Full article

Wood, steel, and concrete constitute the three predominant structural materials employed in contemporary commercial and residential construction. In composite applications, bond interfaces between these materials represent critical structural junctures that frequently exhibit a reduced load-bearing capacity, rendering them susceptible to the initiation of cracks. To elucidate the fracture propagation mechanisms at composite material interfaces, this study implements the cohesive zone method (CZM) to numerically simulate interfacial cracking behavior in two material systems: glued laminated timber (GLT) and reinforced concrete (RC). The adopted CZM framework utilizes a progressive delamination approach through cohesive elements governed by a bilinear traction–separation constitutive law. This methodology enables the simulation of interfacial failure through three distinct fracture modes: mode I (pure normal separation), mode II (pure in-plane shear), and mixed-mode (mode m) failure. Numerical models were developed for GLT beams, RC beams, and RC slab structures to investigate the propagation of interfacial cracks under monotonic loading conditions. The simulation results demonstrate strong agreement with experimental cracking observations in GLT structures, validating the CZM’s efficacy in characterizing both mechanical behavior and crack displacement fields. The model successfully captures transverse tensile failure (mode I) parallel to wood grain, longitudinal shear failure (mode II), and mixed-mode failure (mode m) in GLT specimens. Subsequent application of the CZM to RC structural components revealed a comparable predictive accuracy in simulating the interfacial mechanical response and crack displacement patterns at concrete composite interfaces. These findings collectively substantiate the robustness of the proposed CZM framework in modeling complex fracture phenomena across diverse construction material systems. Full article

Concrete-like composites are widely used in the building of civil engineering applications such as houses, dams, and roads. Mesoscale modeling is a powerful tool for the physical and mechanical analysis of concrete-like composites. A novel discrete element method (DEM)-enhanced external force-free method for multi-phase concrete-like composite modeling with an interface transition zone (ITZ) is presented in this paper. Firstly, randomly distributed particles with arbitrary shapes are generated based on a grading curve. Then, a Minkowski sum operation for particles is implemented to control the minimum gap between adjacent particles. Secondly, a transition from particles to clumps is realized using the overlapping discrete element cluster (ODEC) method and is randomly placed into a specific space. Thirdly, the DEM simulation with a simple linear contact model is employed to separate the overlapped clumps. Meanwhile, the initial position, displacement, and rotation of clumps are recorded. Finally, the mesoscale model is reconstructed based on the displacement and rotation information. The results show that this method can efficiently generate multi-phase composites with arbitrary particle shapes, high volume fractions, an overlapped ITZ, and a periodic structure. This study proposes a novel, efficient tool for analyzing and designing composite materials in resilient civil infrastructure. Full article

This study focuses on the compression area of a cryogenic air separation unit (ASU). The mechanism of exergy consumption in the compressor was revealed. The influence of the compression ratio and of the isentropic efficiency per stage give arguments for proper choice of these decisional parameters. For the purchase cost of the compressor, an exergoeconomic correlation based on the exergetic product represented by the compression ratio and the isentropic efficiency as the Second Law coefficient of performance was used instead of the common thermo-economic one based only on the cost of materials. The impact of the suction temperature on the compressor operating performance is shown, making the gap between the compression stage and the associated intercooler. After optimization of the global system, a specific exergy destruction is assigned to each inter-stage compression cooler. To fit this optimum exergy consumption, a design procedure for the inter-stages and final coolers based on the number of heat transfer units (NTU-ε) method and the number of exergy units destroyed (NEUD) is shown. Graphs are provided that make the application of the method straightforward and much easier to use compared to the usual logarithmic mean temperature difference. A 25% increase in the compression ratio per stage leads to a decrease in the exergy efficiency of 3%, while the purchase cost of the compressor rises by 80%. An increase in the isentropic efficiency of the compressor from 0.7 to 0.85 leads to an increase in the exergetic performance coefficient of 21%, while the compressor purchase cost triples. Full article

The need for renewable alternatives to petroleum-based polymers is growing in response to environmental concerns and resource depletion. Polyimides (PIs), which are traditionally synthesized from petroleum-derived monomers, raise sustainability issues. In this work, renewable 2,5-furandicarboxylic acid (FDCA) was employed as a sustainable feedstock to synthesize a bio-based diamine monomer, N,N′-bis(4-aminophenyl)furan-2,5-dicarboxamide (FPA). Subsequently, FPA was polymerized with various aromatic dianhydrides through thermal imidization, yielding four distinct bio-based polyimide (FPA-PI) films. The resulting films exhibited exceptional thermal stability, with 5% weight loss temperatures exceeding 425 °C and char yields ranging from 54% to 60%. Mechanical characterization revealed high elastic moduli (2.14–3.20 GPa), moderate tensile strengths (50–99 MPa), and favorable aging resistance. Gas permeation tests demonstrated promising CO₂/N₂ separation performance, with FPA-DODDA achieving superior CO₂/N₂ selectivity (27.721) compared to commercial films such as Matrimid^®, polysulfone, and polycarbonate, while FPA-BPFLDA exhibited enhanced CO₂ permeability (P(CO₂) = 2.526 Barrer), surpassing that of Torlon^®. The CO₂/N₂ separation performance of these FPA-PI films is governed synergistically by size-sieving effects and solution-diffusion mechanisms. This work not only introduces a novel synthetic route for bio-based polymers but also highlights the potential of replacing conventional petroleum-based materials with renewable alternatives in high-temperature and gas separation applications, thereby advancing environmental sustainability. Full article

Lithium metal exhibits strong adhesive properties and a highly reactive nature, which complicates conventional mechanical separation methods. Laser cutting, as a contactless process, is possible under a defined drying room atmosphere. However, it is a costly process and therefore not suitable for industrial usage. Consequently, the development of a cost-effective process gas is imperative for the future implementation of lithium metal. In this research, the laser cutting of 30 µm lithium copper composite foil is performed under different process gases (nitrogen and argon) and ambient atmospheres with different water contents to determine the ablation potential depended on the process gas. To assess the laser–material interaction, the impact of pulse repetition frequency and cutting velocity on the material behavior was investigated. To this end, the ablation behavior, the resulting cutting edges, and the electrochemical performance were thoroughly explored. The findings reveal a dependence of the ablation behavior on the water content in the ambient atmosphere, as well as a reduced energy input for a complete shot through when using an inert gas. The resulting cutting edges result in nearly similar outcomes with regard to the heat-affected zone. The electrochemical performance illustrates the influence of the laser process with different gases, taking into account the changed electrochemical impedance spectroscopy. Full article

The relationship between tearing energy and crack growth rates in elastomers is typically divided into three regions—slow crack growth, fast crack growth, and a transitional region—each described by separate power law relationships, requiring six variables to fully characterize the behavior. This study introduces a novel, unified equation that simplifies this relationship by combining two coexisting energy dissipation mechanisms into a single model with only four variables. The model consists of two terms, one for each energy dissipation mechanism: one term is dominant at slow crack growth rates and limited by a threshold energy, and the other is dominant at fast speeds. The transition region emerges naturally as the dominant mechanism shifts. The model’s simplicity enables new advances, such as predicting fast crack growth tearing and transition energies using only slow crack growth data. This capability is demonstrated across a wide range of non-strain crystallizing rubbers, including filled and unfilled compounds, tested at room temperature and elevated temperatures and in both swollen and unswollen states. This model offers a practical tool for material design, failure prediction, and reducing experimental effort in characterizing elastomer performance. Notably, this is the first model to unify slow, transition, and fast crack growth regimes into a single continuous equation requiring only four variables, enabling the prediction of high-speed behavior using only low-speed experimental data—a major advantage over existing six-parameter models. Full article

Efficient coal grinding is a crucial aspect of the energy and mining industries. However, traditional grinding methods are known to be energy-intensive and cause significant wear on equipment as well as negative environmental impacts due to the release of small particles that can harm air quality and affect human health. In response to these challenges, we are conducting research to develop an electric pulse device for coal grinding. This device will use high-voltage discharges in a liquid medium to create shock waves that selectively destroy coal particles while minimizing mechanical damage. The electric pulse installation consisted of a control unit (for monitoring the operating modes of the installation), a generator (for converting the AC input voltage into DC output voltage), a capacitor (for energy storage), a protection system (for shutting down the installation in cases when a voltage exceeding the set safe operating discharge voltage occurs on the capacitor), a spark gap (forming a gap consisting of two conductive hemispherical electrodes separated by an air gap, designed to form an electric spark between conductors), and an electric pulse grinding device. The input material for each experiment had consistent parameters: the coal particles were diameter 8–10 mm and weighed 400 g. Coal was processed using the electric pulse method with various voltage values, numbers of pulses, capacitor capacities, and pulse frequencies. The yield of the final product depended on these parameters, and effective settings for producing coal powder were identified. The research results demonstrate that a flat metal mesh plate is effective as the negative electrode in the electric pulse grinding device. Full article

This study analyses the effect of lignin extracted from the Dominico-Harton banana on the physicochemical properties of biodegradable methylhydroxyethylcellulose (MHEC) composites. Lignin was obtained by grinding and sieving, followed by treatment with sulphuric acid and subsequent separation via centrifugation. Films were developed using the casting method, incorporating lignin and glycerol in a matrix of MHEC dissolved in distilled water. They were characterised according to their physical, barrier, mechanical, optical, and antioxidant properties, using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The results showed that lignin provides antioxidant capacity and improves mechanical and barrier properties, while MHEC contributes flexibility and biodegradability. These films have a dense and resistant structure, with potential applications in food packaging, agriculture, and medicine. The research highlights the use of agricultural waste to develop sustainable materials as an alternative to conventional plastics. Full article

This study proposes an innovative design strategy for molybdenum disulfide (MoS₂) optoelectronic devices based on three-dimensional folded configurations. A “Z”-shaped folded MoS₂ device was fabricated through mechanical exfoliation combined with a pre-strain technique on elastic substrates. Experimental investigations reveal that the geometric folding deformation induces novel photocurrent response zones near folded regions beyond the Schottky junction area via band structure reconstruction, achieving triple polarity switching (negative–positive–negative–positive) of photocurrent. This breakthrough overcomes the single-polarity separation mechanism limitation in conventional planar devices. Scanning photocurrent microscopy demonstrates a 40-fold enhancement in photocurrent intensity at folded regions compared to flat areas, attributed to the optimization of carrier separation efficiency through a pn junction-like built-in electric field induced by the three-dimensional configuration. Voltage-modulation experiments show that negative bias (−150 mV) expands positive response regions, while +200 mV bias induces a global negative response, revealing a dynamic synergy between folding deformation and electric field regulation. Theoretical analysis identifies that the band bending and built-in electric field in folded regions constitutes the physical origin of multiple polarity reversals. This work establishes a design paradigm integrating “geometric deformation-band engineering” for regulating optoelectronic properties of two-dimensional materials, demonstrating significant application potential in programmable photoelectric sensing and neuromorphic devices. Full article

Due to its distinctive two-dimensional structure and high specific surface area, graphene oxide (GO) is expected to be a very promising material to be used for membrane separation. Not only can it improve the mechanical strength, surface wettability, and thermal stability of the membrane, but it can also improve the filtration performance and shelf life of the polymer membrane. Graphene oxide/poly(meta-phenylene isophthalamide) (GO/PMIA) nanofiber membranes were prepared by means of an electrospinning technique. The effects of adding different amounts of GO on the PMIA nanofiber membranes were studied. The results indicated that the GO had a strong affinity with the PMIA matrix by forming hydrogen bonds. The composite nanofiber membranes exhibited better filtration and thermostability performance than those of the pristine membrane. As the loading amount of GO was 1.0 wt%, the air filtration efficiency of the composite nanofiber membrane was 97.79%, the pressure drop was 85.45 Pa and the glass transition temperature was 299.8 °C. Full article

Advanced photocatalytic materials for environmental cleanup need to be developed in response to growing concerns about water pollution. This paper presents a novel N-doped hollow carbon spheres (NHCSs)-supported Co₂SnO₄/WS₂ heterostructure synthesized using a hydrothermal approach and examined using various characterization techniques to evaluate the crystal structures, functional groups, surface morphology, chemical properties, and optical characteristics. The photocatalytic performance of the Co₂SnO₄/WS₂@NHCSs composite was assessed by degrading Congo red (CR) under visible light, resulting in a notable degradation rate of 87.22% in 60 min. The enhanced degradation efficiency is ascribed to the Z-scheme heterojunction charge-transfer mechanism, which augments sustained charge separation while suppressing recombination under visible-light irradiation. Furthermore, the quenching experiments revealed that specific superoxide radicals (^•O₂^-) and hydroxyl radicals (^•OH) were integral to the degradation reaction, and a potential Z-scheme charge-transfer pathway mechanism for the effective Co₂SnO₄/WS₂@NHCSs photocatalysts was also suggested. The potential degradation mechanism was suggested using LC-MS analysis. This study highlights the promise of Co₂SnO₄/WS₂@NHCSs composites for practical wastewater treatment applications, providing a sustainable and effective solution for environmental remediation. Full article

This work provides a comprehensive review of the recent advancements in the toughening modification methods for epoxy resins. The study explores a variety of approaches, including the incorporation of liquid rubbers, core–shell rubber particles, thermoplastic resins, hyperbranched polymers, and the nanoparticle toughening method, each of which contributes to improving the mechanical properties and fracture toughness of epoxy resins. Special attention is given to the mechanisms underlying these toughening methods, such as reaction-induced phase separation, crack pinning, and energy dissipation through particle deformation. The paper also examines the synergistic effects achieved by combining different toughening agents, such as phenoxy thermoplastic rubber and core–shell rubber particles, which significantly enhance the critical fracture energy and impact strength of epoxy composites. Additionally, the challenges associated with each method, such as the potential reduction in mechanical properties and the influence of phase separation on material performance, are discussed. Through a detailed analysis of experimental studies, this paper highlights the effectiveness of various toughening strategies and suggests future research directions aimed at further optimizing epoxy resin toughening techniques for diverse industrial applications. Emerging computational modeling and machine learning applications in epoxy resin development are also systematically reviewed to highlight their potential in advancing predictive design frameworks. Full article

Multilayer plastic films (MPFs) are widely used in the food industry. Despite its widespread use, the recycling of MPF remains a challenge due to its complex structure. Solvent-based recycling is more complex and costly than conventional mechanical recycling, which remains the most widely used method despite its technical and economic limitations. This study investigates the conventional mechanical recycling of post-consumer MPF without separating its constituent layers. Samples were prepared using a thermal extrusion cycle with the control of temperature, speed and sample size to improve the melt state, homogeneity and mechanical response of the mixture. The results of the physicomechanical characterization in this research study show that the proper selection of the extrusion parameters for a fine multilayer waste of 2 mm particle size, has a positive impact, for instance, on the final maximum strength of the recycled material, demonstrating an increase of up to 40 and 70% in tensile and flexural properties, respectively. The proposed mechanical recycling of post-consumer MPF without separation of its constituents can produce a material with mechanical properties comparable to those of low-density polyethylene and polypropylene. These findings could significantly benefit the recycling industry by reducing plastic pollution and allowing for creating new products with specific mechanical properties tailored for different applications. Full article

This study focuses on enhancing the photoelectrocatalytic (PEC) performance of LaFeO₃ photocathodes by incorporating Ag nanocrystals. LaFeO₃, a perovskite-type metal oxide semiconductor, has potential in PEC water splitting but suffers from fast charge carrier recombination. Ag nanoparticles are introduced due to their surface plasmon resonance (SPR) property and ability to form Schottky junctions with LaFeO₃. A series of Ag/LaFeO₃ materials are prepared using the molten salt method for LaFeO₃ synthesis and the direct reduction method for Ag loading. The results show that Ag nanoparticles are uniformly dispersed on LaFeO₃. The 3 mol% Ag/LaFeO₃ photocathode demonstrates a remarkable ninefold increase in photocurrent density (15 mA·cm⁻² at −0.2 V vs. RHE) compared to pure LaFeO₃ (1.7 mA·cm⁻²). The band gap of LaFeO₃ is reduced from 2.07 eV to 1.92 eV with 3 mol% Ag loading, and the charge transfer impedance is reduced by 77%, while the carrier concentration increases by 2.3 times. The novelty of this work lies in the comprehensive investigation of the interaction mechanisms between Ag nanoparticles and LaFeO₃, which lead to enhanced light absorption, improved charge separation, and increased electrochemical activity. The optimized Ag loading not only improves the photocatalytic efficiency but also enhances the stability of the photocathode. This work provides valuable insights into the interaction between Ag and LaFeO₃, and offers experimental and theoretical support for developing efficient photocatalytic materials for PEC water splitting. Full article