Search Results (351)

Tetracycline-class antibiotics are persistent contaminants in aquatic environments and are difficult to remove by conventional treatment processes. In this study, a recoverable granular MIL-101(Fe)/γ-Al₂O₃ catalyst was prepared through ligand anchoring followed by secondary Fe-MOF growth on spherical γ-Al₂O₃ and applied to catalytic ozonation of tetracycline (TC) under ordinary-bubble and microbubble-assisted operation. Structural characterization supported the formation of Fe-containing MOF domains on the alumina support, accompanied by an increase in BET surface area from 164.28 to 210.05 m² g⁻¹ and enhanced Lewis-acid-related pyridine-IR signals. Under conventional bubbling ozonation, the optimized catalyst achieved 67.93% apparent UV–Vis-based TC removal during an overall 50 min run consisting of 30 min dark adsorption followed by 20 min ozonation. In a 12 L microbubble reactor, the catalyst-assisted system reached 93.74% apparent UV–Vis-based TC removal at pH 6 with 100 g catalyst and 6 mg min⁻¹ fed ozone, showing higher apparent removal than ordinary ozonation, microbubble ozonation, and ordinary-bubble catalytic ozonation under the tested configuration. Phosphate-blocking and radical-quenching experiments were consistent with the involvement of Lewis-acid-related sites, hydroxyl radicals, and superoxide-related pathways, but these tests are interpreted as indirect mechanistic evidence. LC-MS analysis suggested possible hydroxylation, demethylation, deamidation, ring opening, and low-molecular-weight product formation. The system also transformed chlortetracycline, oxytetracycline, and doxycycline and reduced COD and TOC in a simulated mixed-antibiotic matrix. Because parent-compound HPLC/LC-MS time-series quantification, ozone utilization/off-gas ozone measurement, bubble-size/kLa analysis, and ICP-based Fe loading/leaching data were not available, the present work is positioned as an apparent catalyst–reactor coupling study rather than a complete catalytic, hydrodynamic, or process-level demonstration. Full article

The algae-based landfill leachate (LL) treatment system has been proved promising for nutrient recycling and biomass production at lab- or small-scale photobioreactors (PBRs). However, many assessment tools such as techno-economic analyses (TEAs) usually utilize parameters from small-scale experiments as input data to predict the potential performance of commercial large-scale or full-scale bioreactors. Reliability of using data from lab-scale for commercial large-scale estimation is still uncertain. This study compared the performance of three photobioreactor systems that differed simultaneously in scale, geometry, light intensity, mixing mode, and aeration: 0.125 L small-scale flask, 1 L medium-scale tubular PBR, and 15 L wall-shaped PBR for real LL treatment. The 1 L medium-scale tubular photobioreactor outperformed the other two systems in biomass growth rate and the rates of nitrogen and phosphorus removal, even though all three systems removed nearly all NH₄-N and PO₄-P (≈100%) within two weeks. Possible reasons for this better performance include stronger illumination, a bubbling aeration mode, the reactor shape (which improves mixing), and higher surface area to volume ratio × light intensity. According to these results, using relatively small-scale flask experimental data for predictive analysis of industrial-scale algal systems could be inadequate. In this study, volumetric optical radiation (VOR) serves as a promising preliminary descriptive indicator to reflect the overall performance of an algal-based treatment system. Full article

Expanded snack extrusion is governed by tightly coupled interactions among raw material composition, moisture, barrel temperature, screw speed, feed rate, screw configuration, die geometry, and energy input. These variables affect not only final responses such as expansion ratio, bulk density, hardness, crispness, and water absorption or solubility indices, but also intermediate state variables including specific mechanical energy (SME), melt temperature, die pressure, melt viscosity, and bubble growth dynamics. As a result, modelling has become essential for product design, process optimisation, and scale-up. This review critically evaluates the major classes of models used to describe process–structure–quality relationships in the extrusion of expanded snacks. The literature shows that empirical regression and response surface methodology (RSM) remain the most widely applied tools because they are experimentally efficient and easy to interpret. However, mixture-process designs are more appropriate when formulation and operating variables are changed simultaneously, while phenomenological and mechanistic approaches provide better physical insight into expansion and structure development. More recently, machine-learning and interpretable artificial intelligence approaches have demonstrated strong predictive capability when large, well-curated datasets are available. Across model families, a consistent theme is that operating variables act on final product quality through intermediate process state variables rather than independently. On that basis, this review proposes a practical hybrid framework for expanded snack extrusion: a mixture-process quadratic model augmented with SME, die pressure, melt temperature and shear-related state variables, and structured in three levels linking (i) controllable inputs to state variables, (ii) state variables to measurable quality attributes, and (iii) quality attributes to a gold-standard product target or sensory-control criterion. Such a model offers a realistic balance between predictive performance, physical interpretability, experimental burden, and industrial usefulness, while also providing a clear pathway toward future digital twin and machine-learning-enabled optimisation. Full article

Oxygen transfer enhancement in aquaculture was investigated using a low-cost fine-bubble spray system operated under controlled hydrodynamic conditions. Experiments were conducted under oxygen-depleted conditions (initial DO = 2.4 mg L⁻¹), and oxygen transfer kinetics were evaluated using the dynamic method. The dissolved oxygen concentration increased to 6.2 mg L⁻¹ within 1 h, corresponding to a net oxygen transfer of 9.55 ± 0.46 g. The volumetric mass transfer coefficient (kLa) was determined to be 1.44 h⁻¹ (R² = 0.97), while the specific oxygen transfer efficiency (SOTE) reached 76.4 ± 7.8 gO₂ kWh⁻¹. Dimensionless analysis (Re ≈ 2 × 10⁴, Sc ≈ 500, Sh ≈ 682) indicates a turbulent, convection-dominated transport regime. Biological observations showed a 43% increase in fish growth under spray-assisted conditions, indicating improved oxygen availability. The observed oxygen transfer enhancement was primarily associated with hydrodynamic interfacial area generation rather than diffusion-limited transport. The low-power configuration and simplified system design suggest potential applicability for decentralized aquaculture operations. The proposed approach also provides an engineering framework for evaluating low-cost aeration technologies under aquaculture operating conditions. Full article

Foam injection moulding (FIM) enables lightweight thermoplastic parts, but current process simulations do not resolve microstructure formation. This work presents a micro-scale CFD framework for FIM that captures gas–melt interaction and bubble morphology. A two-phase, compressible volume-of-fluid solver (OpenFOAM) with surface tension and viscoelastic Phan–Thien–Tanner rheology is coupled to a nucleation pre-processor based on classical nucleation theory, which places bubbles stochastically using macro-scale pressure and temperature histories. The approach was demonstrated on a plate geometry using a 2D through-thickness section to investigate bubble nucleation, deformation, coalescence, and interaction under realistic process conditions. The simulations reproduced characteristic morphology trends across the thickness. In particular, the predicted aspect ratio and orientation show the expected skin–core behaviour and agree qualitatively with experimental observations. These results demonstrate that the framework can describe morphology development beyond simplified spherical-cell assumptions and provides a proof of concept for multiscale coupling between macro-scale process conditions and micro-scale foam structure evolution. A simplified surrogate growth representation was used to enable bubble expansion; however, a physically based mass-transfer model is required for quantitatively accurate growth kinetics. Full article

The objective of this study was to evaluate the potential of age Opuntia-derivated digestate (OpDcm) as a nutrient source for photosynthetic microbial consortia (PMC), aiming to reduce dependence on mineral media and promote the valorization of locally available biomass in arid and semi-arid regions. Batch cultures were performed in bubble column photobioreactors (BCPBR) and open raceway (ORPBR) photobioreactors using different proportions of OpDcm and BG11₀ to assess biomass production, chlorophyll a dynamics, and physicochemical responses of a PMC dominated by Nostoc sp. Chemical characterization showed that OpDcm contained higher levels of K, Ca, Mg, and Mn than BG11₀, providing a robust ionic matrix for initial growth; however, potential limitations in P, Mg, and Fe were identified. In both BCPBR and ORPBR systems, OpDcm demonstrated nutrient compositions that stimulated biomass production in the PMC at levels comparable to those achieved with BG11₀ medium. Statistical analyses showed that specific treatments, particularly T1 (10% OpDcm in BCPBR) and T3 (10% OpDcm + 2.5% BG11₀ in ORPBR), produced biomass yields similar to or higher than those obtained with the conventional BG11₀ medium. However, chlorophyll a concentration was lower in OpDcm treatments due to limited light transmission and micronutrient constraints. The N–NH₄⁺ dynamics in BCPBR and ORPBR exhibited pronounced variability among the evaluated culture media, spanning from negligible changes (<1 mg L⁻¹) over the entire cultivation period to sustained ammonium production rates of 2–3 mg L⁻¹ day⁻¹. Morphological analysis confirmed a consortium dominated by Nostoc sp., supported by pH values within the optimal range (8–9). Overall, the use of age-Opuntia-derived digestates demonstrated it can serve as a partial or total substitute for a low-cost nutrient source for cyanobacterial cultivation, underscoring their relevance to circular bioeconomy strategies for producing photosynthetic biomass. Full article

Efficient froth flotation of fine smithsonite from slime-containing zinc oxide ores remains challenging due to low particle–bubble collision efficiency and strong surface hydration. Conventional agglomeration methods suffer from high reagent costs, non-selective agglomeration, or reduced surface hydrophobicity. Herein, non-hydrolyzable alkali metal salts, exemplified by NaCl, were introduced as novel and efficient coagulants to enhance the flotation of fine smithsonite, and the underlying mechanisms were systematically elucidated. In the sodium oleate flotation system, alkali metal ions promoted the formation and agglomeration of oleate micelles. Meanwhile, they significantly facilitated collector adsorption onto the smithsonite surface and improved the hydrophobicity of the mineral particles. At high ionic strengths, compression of the electrical double layer reduced the Zeta potential and interparticle electrostatic repulsion. These synergistic mechanisms promoted the growth and stability of hydrophobic aggregates, increasing their collision and attachment efficiency with bubbles. By employing non-hydrolyzable salts, the loss of surface hydrophobicity typically induced by conventional hydrolyzable coagulants was avoided. Validation tests on an industrial zinc oxide ore confirmed the feasibility of this approach, offering a promising pathway to mitigate zinc resource losses and associated environmental hazards. Full article

Droplets impacting heated porous surfaces trigger a complex process involving liquid and vapor penetration, as well as the growth and rupture of internal bubbles. In the current paper, four types of sintered porous substrates with different permeability and surface roughness are used. The droplet impact process on heated porous surfaces is visualized by high-speed photography and image processing algorithms. The boiling phase transition characteristics of propylene glycol–propanetriol binary droplets impact on different heating surfaces and the variation pattern of the number and diameter of secondary droplets splashed during the boiling process were investigated. The results show that the surface properties of the porous medium and the composition of the droplet solution have a large effect on the boiling state of the droplets as well as the number and diameter of the secondary droplets. An elevated proportion of propanetriol in solution makes it difficult for droplets to penetrate porous substrates, and it is more difficult for droplets on substrates with large pore size and roughness to undergo film boiling, with more secondary droplets erupting during boiling. Full article

This study addresses the critical challenge of low reactivity and environmental leaching associated with high-volume phosphogypsum by implementing an ettringite seed induction strategy to optimize foam concrete performance. These issues may lead to insufficient mechanical reliability, weak structural integrity, and environmental safety concerns in engineering applications. The results demonstrate that an optimal 2% seed dosage increases the 28-day compressive strength to 4.7 MPa, which represents a 150% improvement over the control while maintaining mass loss below 3.0% after 15 wet–dry cycles. Microstructural analysis reveals that the seeds serve as heterogeneous nucleation sites that help mitigate the inhibitory effects of phosphogypsum impurities to facilitate the growth of a dense 3D interlocking ettringite framework within the pore walls. This densification significantly reinforces the mechanical skeleton and reduces phosphorus leaching by 64.2%. However, excessive seed dosages at or above 5% may promote local AFt accumulation and rheological slurry-bubble mismatch which could contribute to microstructural defects and strength regression. The findings are expected to provide a scientific basis for the engineering application of high-volume phosphogypsum in foam concrete, particularly as lightweight fillers and non-load-bearing construction materials for sustainable construction. Full article

Protrusions on the flow-passing surfaces of hydraulic machinery readily induce localized cavitation and exacerbate cavitation erosion damage. This study investigates the influence of a spherical cap protrusion on a flat wall on the collapse dynamics of cavitation bubbles. By integrating high-speed photography experiments with Kelvin impulse theory, an impulse model is constructed based on boundary treatment and potential flow superposition. The dynamic evolution characteristics of cavitation bubbles at both symmetric and asymmetric positions are systematically analyzed, with emphasis on the effects of the spherical cap angle and bubble azimuthal angle on bubble morphology evolution, bubble wall collapse velocity, and the magnitude and direction of the Kelvin impulse. The results indicate that as the spherical cap angle increases, the non-spherical collapse of bubbles at symmetric positions becomes substantially more pronounced, and the collapse mode transitions from flat wall-dominated to protrusion-dominated behavior. At asymmetric positions, a larger spherical cap angle intensifies the non-uniformity of the bubble wall collapse velocity: the minimum velocity continues to decrease, and the location of this extremum shifts toward the side adjacent to the protrusion. Meanwhile, the Kelvin impulse magnitude exhibits accelerating growth, and its direction reorients from perpendicular to the wall toward the protrusion structure. Full article

We investigate laser wakefield electron acceleration in a periodic plasma density profile using 2D PIC simulations with the EPOCH code. The profile of the electron density has the form $n\left(x\right)=n_0\left(1+\delta sin2\pi x/x_0\right)$, where $n_0$ is the steady electron density, $x_0=100\mathrm{m}$ is the spatial periodicity in the laser propagation direction and $\delta$, taking the values 0, $0.1$, $0.3$, $0.5$ and $0.7$, is the modulation parameter. The bubble size varies with the modulated plasma density, thereby influencing the electron acceleration, which occurs within a continuously changing bubble structure. We propose an analytical model to estimate the energies of the accelerated electrons, and evaluate the maximum electron energies at $500 \mathrm{f}\mathrm{s}$ intervals for the five modulated density profiles. We then calculate the dephasing and depletion lengths for these modulated plasma profiles and examine their dependence on $\delta$. The results show a growth in both lengths with $\delta$, with depletion being the main limitation in these cases. Additionally, we compute and compare the transverse emittance of the self-injected electron bunches corresponding to the various density profiles at the same simulation time, and other characteristics, like the center energy and energy spread. Emittance is observed to experience a decrease with the increase in the modulation parameter. Full article

This study investigates the selective synthesis of α- and γ-alumina nanoparticles using plasma-induced microbubbles. Although plasma-induced bubbles provide an effective reaction environment for the synthesis of nanomaterials, precise phase control remains challenging. Herein, we demonstrate that the modulation of the pulse off time regulates the thermal environment within the bubbles. Optical emission spectroscopy revealed that a shorter off time maintains a high electron temperature, indicating substantial heat accumulation. This high-energy state promotes the atomization of the precursor mist and the subsequent growth of molten droplets, providing sufficient activation energy for the formation of the thermodynamically stable α-phase. In contrast, a longer off time leads to the formation of a metastable γ-phase because of insufficient heating and rapid quenching. These findings prove that alumina nanoparticles with desired crystal phase and size can be synthesized by controlling the thermal energy inside the plasma-induced microbubbles. Full article

Conductive polymer microcellular foamed materials are a type of functional composite that combines lightweight cell structures with controllable conductivity. Their core feature lies in regulating the cell structure of the material through microcellular foaming technology, along with the introduction of conductive fillers or the intrinsic conductivity of the polymer, to achieve enhanced electrical performance. This paper systematically reviews conductive polymers and their microcellular foamed materials, highlighting research progress in foaming mechanisms, preparation processes, and functional applications. It first analyzes the key mechanisms of bubble nucleation, growth, and stabilization during the microcellular foaming of conductive polymers. Then, it elaborates on the research status and functional mechanisms of these materials in three typical application scenarios: electromagnetic shielding, flexible sensors, and thermal management. Finally, it outlines the future development directions of conductive polymer microcellular foamed materials in multifunctional integration, green fabrication, and intelligent applications, aiming to provide theoretical guidance and technical pathways for future research. Full article

Lactic Acid Bacteria (LAB)-derived antimicrobial compounds are recognized as a promising source of novel antimicrobial agents, particularly for the treatment of Methicillin-Resistant Staphylococcus aureus (MRSA), where the mode of action and associated cellular effects remain largely unexplored. This study aims to evaluate antibacterial activity of Limosilactobacillus fermentum YTPP05 isolated from pickled radish against MRSA. Upon the initial antibacterial evaluations, it was found that strain YTPP05 inhibited the growth of MRSA isolates. Multiplex PCR identified multiple resistance genes in our MRSA strains, including mecA, blaZ, and aacA genes, aligning with antibacterial susceptibility profiles determined by the disc diffusion assay. An agar overlay assay showed that YTPP05 possessed antibacterial potential, with the largest inhibition zone diameters of 40.83 ± 8.43 mm, while the inhibition zones of the Cell Free Supernatant (CFS) of YTPP05 by an agar well diffusion were 27.16 ± 2.93 mm against the MRSA isolates. The minimum inhibitory concentration and minimum bactericidal concentration of YTPP05-derived CFS were 125 mg/mL. Scanning Electron Microscopy (SEM) demonstrated YTPP05 extracts caused cell membrane disruption, bubble-like protrusion, and cell lysis. Collectively, this study highlights the anti-MRSA potential of YTPP05 as an alternative antimicrobial agent for combating MRSA infections. Full article

Background: High-risk neuroblastoma (NB) is a pediatric malignancy associated with metastases and an immunosuppressive tumor microenvironment. Standard-of-care treatments like chemotherapy are often ineffective, which motivates the investigation of adjuvant approaches. Histotripsy is a noninvasive focused ultrasound therapy that ablates tissue through the mechanical action of bubble clouds. In addition to disruption of the targeted tumor, non-targeted lesions may exhibit growth delay after the histotripsy procedure. The primary hypothesis of this study was histotripsy-induced shifts in the tumor microenvironment will improve the response of metastatic NB to chemotherapy. Methods: Female A/J mice flanks were inoculated bilaterally with 1 × 10⁶ Neuro-2a cells. Histotripsy was applied to one tumor (200–500 mm³), with or without concurrent administration of liposomal doxorubicin (LDOX). The contralateral tumor served as a model of non-targeted distal metastases. Following treatment, tumors were monitored indefinitely for growth, or assessed after 5–7 days with flow cytometry, single-cell RNA sequencing, and immunohistochemistry. Results: Histotripsy alone delayed the growth of treated and contralateral tumors relative to controls (p = 0.01 and p < 0.0001, respectively) and increased CD8⁺ T and CD11b⁺ cells (p < 0.05 for both comparisons). Further, NB cells in targeted and contralateral tumors exhibited a decrease in c-Myc expression and cell-cycle activity, and upregulation of interferon and apoptosis pathways. Histotripsy combined with LDOX had the longest delay in tumor growth (p < 0.0001 vs. untreated controls; p < 0.001 vs. other arms) and greatest expression of CD8⁺ and MOMA staining. Conclusions: These findings indicate that histotripsy induces a systemic antitumor immune response that potentiates chemotherapy efficacy in this model of metastatic NB. Full article