Search Results (271)

This study reports the development and optimization of a Melissa officinalis oil-based nanoemulgel for transdermal delivery using a Design-of-Experiments (DoE) approach. A Central Composite Design (CCD) was applied to optimize Tween 80 concentration and homogenization time, resulting in a nanoemulsion with a droplet size of 127.31 nm, PDI of 17.7%, and zeta potential of −25.0 mV, indicating good colloidal stability. FTIR analysis confirmed the presence of functional groups such as O–H, C=O, and C–O–C, supporting the oil’s phytochemical richness and therapeutic potential. DSC analysis revealed enhanced thermal stability and successful encapsulation, while SEM imaging showed a uniform and spherical microstructure. The drug release followed Higuchi kinetics (R² = 0.900), indicating diffusion-driven release, with the Korsmeyer–Peppas model (n = 0.88) suggesting anomalous transport. Antibacterial studies showed inhibition of Staphylococcus aureus (MIC = 250 µg/mL) and Escherichia coli (MIC = 500 µg/mL). In vivo anti-inflammatory testing demonstrated significant edema reduction (p < 0.05) using a carrageenan-induced rat paw model. These results support the potential of Melissa nanoemulgel as a stable and effective topical therapeutic for inflammatory and microbial skin disorders. Full article

This study develops an incompressible two-phase flow solver based on the open-source OpenFOAM platform, employing the volume-of-fluid (VOF) method to track the gas–liquid interface and utilizing the MULES algorithm to suppress numerical diffusion. This study provides a comprehensive investigation of the spreading dynamics of droplet pairs near walls, along with the presentation of a corresponding mathematical model. The numerical model is validated through a two-dimensional axisymmetric computational domain, demonstrating grid independence and confirming its reliability by comparing simulation results with experimental data in predicting drConfirmedoplet collision, spreading, and deformation dynamics. The study particularly investigates the influence of surface wettability on droplet impact dynamics, revealing that increased contact angle enhances droplet retraction height, leading to complete rebound on superhydrophobic surfaces. Finally, a mathematical model is presented to describe the relationship between spreading length, contact angle, and Weber number, and the study proves its accuracy. Analysis under logarithmic coordinates reveals that the contact angle exerts a significant influence on spreading length, while a constant contact angle condition yields a slight monotonic increase in spreading length with the Weber number. These findings provide an effective numerical and mathematical tool for analyzing the spreading dynamics of droplet pairs. Full article

Hydrogen is a promising alternative fuel for internal combustion engines due to its high specific energy, fast flame speed, and carbon-free combustion. In dual-fuel operation, it offers a practical route to reducing greenhouse gas emissions while remaining compatible with existing engine hardware. This work evaluates how the hydrogen energy substitution ratio (HSR = 50, 70, and 90%) influences spray dynamics, combustion characteristics, and emissions in a heavy-duty compression ignition engine. Simulations are validated against experiments and use a URANS RNG k–ε framework with a hybrid combustion model: the Eddy Dissipation Concept (EDC) coupled with detailed kinetics (111 species, 768 reactions) for auto-ignition and diffusion burning of diesel, and a G-equation for propagation of a hydrogen-rich premixed flame. The results reveal clear spray–combustion linkages. At HSR 50, the higher Weber number induces stronger breakup, yielding a smaller Sauter mean diameter and higher number-averaged droplet velocity; at HSR 90, the spray is more stable and less atomized, with larger droplets and a shorter vapor penetration length. Increasing the HSR reduces unburned hydrocarbons (UHCs) by more than 50% from HSR 50 to HSR 90 while modestly altering combustion phasing (a later CA50 and a shorter burn duration due to faster hydrogen flame propagation). The validated model provides a practical tool for optimizing dual-fuel settings and HSR–EGR–SOI trade-offs to balance efficiency and emissions. Full article

Background: Onychomycosis responds poorly to topical therapy, and efinaconazole (EFN) has low aqueous solubility. Methods: This study aimed to develop a 10% w/w EFN self-nanoemulsifying system (SNEDDS) with improved solubility, permeation, antifungal activity, and stability. Excipients were screened by EFN saturation solubility. An MCT oil/Solutol HS 15/Labrafil M2125 CS SNEDDS (5/75/20, w/w) was optimized via a pseudo-ternary diagram. Characterization included droplet size, PDI, and zeta potential, morphology, and drug–excipient compatibility. Solubility was measured across pH. Permeation of EFN SNEDDS vs. EFN suspension was tested by Franz diffusion cells. Antifungal activity against Trichophyton rubrum and Trichophyton mentagrophytes was assessed by paper-disc diffusion, and hyphal damage on human nails was examined by SEM. Stability was studied for six months under room, accelerated, and stress conditions. Results: The optimized SNEDDS formed sub-50 nm droplets with low polydispersity and favourable zeta potential. Solubility was maintained across pH, and cumulative permeation increased 13.6-fold versus suspension. Paper-disc assays showed larger inhibition zones at lower EFN doses. SEM on human nails revealed marked hyphal destruction. TEM confirmed spherical nanoemulsion droplets. FT-IR showed no new peaks, supporting compatibility. Particle size, PDI, zeta potential, and drug content remained stable over six months under all storage conditions. Conclusions: A 10% w/w EFN SNEDDS enhanced solubility, transungual permeation, and antifungal efficacy while maintaining robust stability, supporting its potential as an ethanol-free therapy for onychomycosis. Full article

Background: Skin mycoses affect approximately 10% of the global population, and the range of effective topical antifungal agents remains limited. Voriconazole (VRC) is a broad-spectrum triazole with proven efficacy against drug-resistant fungal infections. This study aimed to develop and optimize VRC-loaded microemulsion (ME) polymer gels (Carbopol^®-based) for cutaneous delivery. Selected formulations also contained menthol (2%) as a penetration enhancer and potential synergistic antifungal agent. Methods: A comprehensive screening was performed using pseudoternary phase diagrams to identify stable oil/surfactant/co-surfactant/water systems. Selected MEs were prepared with triacetin, Etocas™ 35, and Transcutol^®, then gelled with Carbopol^®. Formulations were characterized for pH, droplet size, polydispersity index (PDI), and viscosity. In vitro VRC release was assessed using diffusion cells, while ex vivo permeation and skin deposition studies were conducted on full-thickness human skin. Rheological behavior (flow curves, yield stress) and texture (spreadability) were evaluated. Antifungal activity was tested against standard strain of Candida albicans and clinical isolates including a fluconazole-resistant strain. Results: The optimized ME (pH ≈ 5.2; droplet size ≈ 2.8 nm) was clear and stable with both VRC and menthol. Gelation produced non-Newtonian, shear-thinning hydrogels with low thixotropy, favorable for topical application. In ex vivo studies, performed with human skin, both VRC-loaded gels deposited the drug in the epidermis and dermis, with no detectable amounts in the receptor phase after 24 h, indicating retention within the skin. Menthol increased VRC deposition. Antifungal testing showed that VRC-containing gels produced large inhibition zones against C. albicans, including the resistant isolate. The VRC–menthol gel exhibited significantly greater inhibition zones than the VRC-only gel, confirming synergistic activity. Conclusions: ME-based hydrogels effectively delivered VRC into the skin. Menthol enhanced drug deposition and demonstrated synergistic antifungal activity with voriconazole. Full article

The synergistic effect of using D2EHPA and TOPO together to enhance the extraction of samarium(III) from aqueous media via emulsion liquid membrane (ELM) technology was explored. D2EHPA in binary mixtures with TBP and in ternary mixtures with TOPO and TBP was also tested. Among the tested extractants, a binary mixture of 0.1% (w/w) D2EHPA and 0.025% (w/w) TOPO achieved 100% samarium(III) extraction at a low loading. This mixture outperformed D2EHPA-TBP and other systems because D2EHPA strongly binds to Sm(III) ions, while TOPO increases the solubility and transport efficiency of metal complexes. Additionally, process factors that optimize performance and minimize emulsion breakage were examined. Key insights for successfully implementing the process include the following: 5 min emulsification with 0.75% Span 80 in kerosene at pH 6.7 (natural), 250 rpm stirring, a 1:1 internal/membrane phase volume ratio, a 20:200 treatment ratio, and a 0.2 N HNO₃ stripping agent. These insights produced stable, fine droplets, enabling complete recovery and rapid carrier regeneration without emulsion breakdown. Extraction kinetics accelerate with temperature up to 35 °C but declined above this limit due to emulsion rupture. The activation energy was calculated to be 33.13 kJ/mol using pseudo-first-order rate constants. This suggests that the process is diffusion-controlled rather than chemically controlled. Performance decreases with Sm(III) feed concentrations greater than 200 mg/L and in high-salt matrices (Na₂SO₄ > NaCl > KNO₃). Integrating these parameters yields a scalable, low-loading ELM framework capable of achieving complete Sm(III) separation with minimal breakage. Full article

Hydrogel-based biosensors are commonly used in diagnostic applications. However, their performance remains constrained by slow analyte diffusion within polymer matrices, particularly when larger biomolecules are involved. Concave hydrogel geometries present a promising solution to enhance diffusion rates through increased surface area. However, the interfacial dynamics governing their formation must be studied. In this research, we investigated the interfacial dynamics that influence the formation of concave hydrogel discs fabricated by a simple pipetting method. We characterized the fluid interactions occurring during droplet deposition of alginate and CaCl₂ solutions. A three-phase flow model incorporating confocal microscopy validation was employed to simulate time-dependent interfacial behaviors. Concave hydrogel discs fabricated with alginate-first deposition exhibited 83% larger surface area compared to hemispherical counterparts at a CaCl₂: alginate volume ratio of one. Increasing the volume ratio further enhanced both surface area and diameter, though this highlighted limitations for microscopy-based detection. According to our results, reaction speed in alginate concave hydrogel discs can be controlled by varying the volume of CaCl₂ solution while keeping the volume of alginate solution constant, which changes the surface area while maintaining constant hydrogel volume. Full article

The direct relationship between aerosols and clouds strongly influences the effects of clouds on the global climate. Aerosol particles act as cloud condensation nuclei (CCN) and ice nuclei (IN), affecting cloud formation, microphysics, and precipitation, as well as increasing the reflection of solar radiation at the cloud tops. Processes such as gas-to-particle conversion and new particle formation (NPF) control aerosol properties that, together with meteorological conditions, regulate cloud droplet nucleation through Köhler theory and related effects. The indirect aerosol effects described by Twomey and Albrecht demonstrate how changes in aerosols impact droplet number, cloud lifetime, and precipitation efficiency. Cloud microphysical processes, including droplet growth, collision-coalescence, and solid-phase mechanisms such as riming, vapor diffusion, and aggregation, shape precipitation development in warm, cold, and mixed-phase clouds. Ice nucleation remains a significant uncertainty due to the diversity of aerosol types and nucleation modes. This work synthesizes these physical interactions to better understand how the chemical and physical properties of aerosols influence cloud and precipitation processes, supporting improvements in weather and climate prediction models despite numerical challenges arising from the complexity of aerosol–cloud interactions. Full article

This study proposes a MPL (microporous layer)–GDL (gas diffusion layer) microstructure reconstruction method based on a novel random reconstruction algorithm. Then the Shan–Chen multi-component and multi-phase lattice Boltzmann method (SC-LBM) is used to systematically describe the influence of different contact angle distributions on the drainage characteristics of the GDL of proton exchange membrane fuel cells (PEMFCs). Meanwhile, the breakthrough time of liquid water, steady-state time, and liquid water saturation are compared. The results show that with the increase in contact angle, the time for the first droplet breakthrough and the steady-state time are significantly shortened, and the saturation of liquid water gradually decreases at the steady state, indicating that increasing hydrophobicity can effectively improve the drainage capacity of the GDL. Several double-gradient and three-gradient contact angle distribution schemes are studied, and it is found that the gradient structure with increasing contact angles along the direction of water flow will lead to prolonged steady-state time and elevated water saturation, which is not conducive to drainage. This study analyzes the drainage process under different wettability gradients considering aspects such as the droplet morphology evolution, flow path, and water distribution mechanism, clarifying the key role of gradient design in GDL water management. This work also provides a theoretical basis and design guidelines for wettability optimization in the GDL of PEMFCs. Full article

This study evaluates the effectiveness of various rejuvenating oils, including soybean oil (N-oil), waste frying oil (F-oil), byproduct oil (W-oil), and aromatic hydrocarbon oil (A-oil), in restoring aged asphalt coatings by reducing asphaltene flocculation and improving colloidal stability. The rejuvenators were incorporated into aged asphalt binder via direct mixing at controlled dosages. Their effects were assessed using microscopy, droplet diffusion analysis, rheological testing (DSR and BBR), and molecular dynamics simulations. The aim is to compare the compatibility, solubility behavior, and rejuvenation potential of plant-based and mineral-based oils. The results indicate that N-oil and F-oil promote asphaltene aggregation, which supports structural rebuilding. In contrast, A-oil and W-oil act as solvents that disperse asphaltenes. Among the tested oils, N-oil exhibited the best overall performance in enhancing flowability, low-temperature flexibility, and chemical compatibility. This study presents a novel method to evaluate rejuvenator effectiveness by quantifying colloidal stability through grayscale analysis of droplet diffusion patterns. This integrated approach offers both mechanistic insights and practical guidance for selecting bio-based rejuvenators in asphalt recycling. Full article

The multiscale interactive system composed of wind, leaves, and droplets serves as a critical dynamic unit in precision orchard spraying. Its coupling mechanisms fundamentally influence pesticide transport pathways, deposition patterns, and drift behavior within crop canopies, forming the foundational basis for achieving intelligent and site-specific spraying operations. This review systematically examines the synergistic dynamics across three hierarchical scales: Droplet–leaf surface wetting and adhesion at the microscale; leaf cluster motion responses at the mesoscale; and the modulation of airflow and spray plume diffusion by canopy architecture at the macroscale. Key variables affecting spray performance—such as wind speed and turbulence structure, leaf biomechanical properties, droplet size and electrostatic characteristics, and spatial canopy heterogeneity—are identified and analyzed. Furthermore, current advances in multiscale modeling approaches and their corresponding experimental validation techniques are critically evaluated, along with their practical boundaries of applicability. Results indicate that while substantial progress has been made at individual scales, significant bottlenecks remain in the integration of cross-scale models, real-time acquisition of critical parameters, and the establishment of high-fidelity experimental platforms. Future research should prioritize the development of unified coupling frameworks, the integration of physics-based and data-driven modeling strategies, and the deployment of multimodal sensing technologies for real-time intelligent spray decision-making. These efforts are expected to provide both theoretical foundations and technological support for advancing precision and intelligent orchard spraying systems. Full article

The excellent moisture transport properties of yarns play a crucial role in improving the liquid moisture transfer behavior within textiles and maintaining their thermal-wet comfort. However, the current research on the moisture management performance of fabrics made from yarns with excellent liquid transport properties primarily compares the wicking results, without considering the varying requirements of testing conditions due to differences in human sweating rates during daily activities. Moreover, the understanding of moisture transport mechanisms in yarns within fabrics under different testing conditions remains insufficient. In this study, two types of twisted combination yarns, composed of hydrophobic profiled polyester filaments and hydrophilic spun yarns to form a hydrophobic-hydrophilic gradient along the axial direction of the yarn, were developed and compared with profiled polyester filaments to understand the liquid migration behaviors in the knitted fabrics formed by these yarns. Results showed that hydrophobic profiled polyester filament yarn demonstrated superior liquid transport performance with infinite saturated liquid supply (vertical wicking test). In contrast, the twisted combination yarns exhibited better moisture diffusion properties under limited liquid droplet supply conditions (droplet diffusion test and moisture management test). These contradictory findings indicated that the amount of liquid moisture supply in testing conditions significantly affected the moisture transport performance of yarns within fabrics. It was revealed that the liquid moisture in the twisted combination yarns migrated through capillary wicking for moisture transfer. Under an infinite saturated liquid supply condition, the higher the content of hydrophilic fibers in the spun yarns, the greater the amount of moisture transferred, demonstrating an excellent liquid transport performance. Under the limited liquid droplet supply conditions, both the volume of liquid water and the moisture absorption capacity of the yarn jointly influence internal moisture migration within the yarn. It provided a theoretical reference for testing the internal moisture wicking performance of fabrics under different states of human sweating. Full article

Background/Objectives: Candidiasis, primarily caused by Candida albicans, and sporotrichosis, mainly caused by Sporothrix schenckii, are skin fungal infections that pose serious threats to global health. The Candida auris is a great concern in immunocompromised individuals, and while Sporothrix brasiliensis cause sporotrichosis, an infection commonly found in cats, this disease can be transmitted to humans through scratches or bites. Existing treatments for these fungal infections often cause problems related to resistance and significant side effects. Consequently, development of alternative therapeutic approaches such as nanotechnology-based topical lipid-based formulations is interesting. Thus, the objectives of this study were to prepare clove oil (CO)-in-water nanoemulsions (NEs) containing amphotericin B (AmB) and characterize them with respect to stability, release profile, and in vitro cytotoxic activity against Candida and Sporothrix strains. As a future alternative for the treatment of fungal skin diseases. Methods: Chemical analysis of clove oil was obtained by GC-MS. The NEs were produced using an ultrasound (sonicator) method with varying proportions of CO, Pluronic^® F-127, and AmB. The NEs were characterized by droplet size, morphology, stability and in vitro release profile. The antifungal and cytotoxic activity against C. albicans, C. auris, S. schenckii, and S. brasiliensis were ascertained employing agar diffusion and colorimetric MTT assay methods. A checkerboard assay was carried out using clove oil and amphotericin B against C. auris. Results: Eugenol was the major compound identified in CO at a concentration of 80.09%. AmB-loaded NEs exhibited particle sizes smaller than 50 nm and a polydispersity index below 0.25. The optimal Ne (NEMLB-05) remained stable after 150 days of storage at 4 °C. It exhibited rapid release within the first 24 h, followed by a slow and controlled release up to 96 h. NEMLB-05 more effectively inhibited C. auris compared to free AmB and also demonstrated greater activity against C. albicans, S. schenckii, and S. brasiliensis. Clove oil and amphotericin B presented synergism inhibiting the growth of C. auris. Conclusions: The selected CO-in-water NEs containing AmB demonstrated promising potential as a topical therapeutic alternative for treating fungal infections. Full article

In recent years, the traditional orchard sprayer has had problems, such as waste of liquid agrochemicals, low target coverage, high manual dependence, and environmental pollution. In this study, an automatic swing-arm sprayer for orchards was developed based on the standardized pear orchard in Pinggu, Beijing. Firstly, the structural principles of a crawler-type traveling system and swing-arm sprayer were simulated using finite element software design. The combination of a diffuse reflection photoelectric sensor and Arduino single-chip microcomputer was used to realize real-time detection and dynamic spray control in the pear canopy, and the sensor delay compensation algorithm was used to optimize target recognition accuracy and improve the utilization rate of liquid agrochemicals. Through the integration of innovative structural design and intelligent control technology, a vertical droplet distribution test was carried out, and the optimal working distance of the spray was determined to be 1 m; the nozzle angle for the upper layer was 45°, that for the lower layer was 15°, and the optimal speed of the swing-arm motor was 75 r/min. Finally, a particle size test and field test of the orchard sprayer were completed, and it was concluded that the swing-arm mode increased the pear tree canopy droplet coverage by 74%, the overall droplet density by 21.4%, and the deposition amount by 23% compared with the non-swing-arm mode, which verified the practicability and reliability of the swing-arm spray and achieved the goal of on-demand pesticide application in pear orchards. Full article

Varshavskii’s ‘Diffusion Theory’, less investigated due to its limited international visibility, can offer one of the simplest and, on the other hand, high-accuracy methods for evaluating the ignition delay of fossil fuel and biofuel droplets, including their blend. In this study, experimental pre-tests were conducted to determine pre-existing subject knowledge on stationary droplet combustion at ambient pressure and temperatures varying from 935 to 1010 K followed by simulation of droplet ignition times. The test fuels were mineral diesel (DF), RME and a 20% RME blend with DF. Simulations were performed for isobaric conditions. Using the detailed transport model and detailed chemical kinetics, the necessary rearrangements were made for the governing equations to meet the criteria for modern fuels (biodiesel, diesel, and blend). The influence of different physical parameters, such as droplet radius, or initial conditions, on the ignition delay time was investigated. The high sensitivity of the proposed methodology to experimental results was substantiated. Full article