Search Results (2,065)

Blackseed oil supplemented with caseinate (CA)–carboxymethyl chitosan (CMCH) composite membranes were evaluated for their functional properties and as edible coating for extending the shelf life of grape tomatoes. Composite films were prepared from equal parts of (CaCa or NaCa) and (CMCH) with or without supplemented 3% blackseed oil (BO) and evaluated for their functional properties. Subsequently, the edible membrane coating was evaluated to extend the shelf life of grape tomatoes (Solanum lycopersicum L.). The water vapor permeability (WVP) of the films was the lowest for the calcium caseinate–carboxymethyl chitosan–blackseed oil (CaCa-CMCH-BO) film (3.01 g kPa⁻¹ h⁻¹ m⁻²). Adding blackseed oil to the edible film matrix also led to a significant increase in its mechanical properties, resulting in tensile strength values of 12.5 MPa and 10.2 MPa and elongation at break values of 90.5% and 100% for NaCa-CMCH-BO and CaCa-CMCH-BO, respectively. The composite films also exhibited good compatibility through hydrogen bonding and hydrophobic interactions, as confirmed by FTIR spectroscopy. The particle size and zeta potential of CaCa-CMCM-BO were 117 nm and −40.73 mV, respectively, while for NaCa-CMCH-BO, they were 294.70 nm and −25.10 mV, respectively. The incorporation of BO into the films resulted in greater antioxidant activity. When applied as an edible film membrane on grape tomatoes, the coating effectively delayed the deterioration of tomatoes by reducing weight loss, microbial spoilage, and oxidative degradation. Compared to the control, the coated fruits had delayed ripening, with a shelf life of up to 30 days, and reduced microbial growth over the entire storage period. Full article

This study utilized tetramethylammonium hydroxide (TMAH) as a substitute for traditional catalysts and successfully incorporated platinum octaethylporphyrin (PtOEP) into SiO₂ nanoparticles (PtOEP@SiO₂) via the Stöber method. Methyl silicone resin was employed as the matrix material, and a drop-coating technique was applied to fabricate thin films of PtOEP@SiO₂ particles for dissolved oxygen (DO) sensing in seawater. By optimizing the concentrations of TMAH and PtOEP, a highly sensitive oxygen-sensing film with a quenching ratio (I₀/I₁₀₀) of 28 was ultimately developed, with a wide linear detection range (0~20 mg/L, R² = 0.994). Stability tests revealed no significant performance degradation during five oxygen–nitrogen cycle tests. After 30 days of immersion in East China Sea seawater, the quenching ratio decreased by only 6%, confirming its long-term stability and excellent resistance to ion interference. This research provides a novel strategy for developing highly reliable in situ marine DO sensors. Full article

The surface of AM60 magnesium alloy was modified with Al-nanocoating ~65.62 nm, using DC magnetron sputtering to enhance its resistance to degradation under aggressive marine ambience. The sputtered Al film showed adhesion to the α-Mg matrix, covering the dispersed particles of the β-Mg₁₇Al₁₂ secondary phase. The aluminum nanofilm was composed of (111) and (200) crystal planes of metallic aluminum (Al⁰) and Al₂O₃ (Al³⁺). After 30 days of immersion in a simulated marine environment (SME, pH 7.8), the Al-AM60 maintained a lower alkaline value (pH~8.13) of SME than that of uncoated AM60, attributed to α-Mg electrochemical oxidation to Al₂O₃ and its posterior dissolution, consuming OH⁻ ions. Consequently, the concentration of the released Mg²⁺ ions from the Al-AM60 surface was reduced ~2.3 times (~15 mg L⁻¹). The Rp (polarization resistance), as inversely proportional to the corrosion current, was extracted from the EIS impedance data fitted to an equivalent electrical circuit. After 30 days in SME solution, the Rp value of the Al-AM60 modified surface was ~3.5 times higher than that of AM60 (~15.46 kΩ cm²), confirming that the sputtered aluminum nano-deposit layer can hinder the corrosion process. These reported findings indicated that sputtered Al nano-coatings can mitigate the surface degradation of Mg-Al alloys in saline aggressive marine environments. Full article

Grape stalk (GS) from winemaking is a waste rich in antioxidant compounds that can be valorized to obtain active food packaging materials. Biocomposite films of poly (butylene succinate) (PBS) and poly(3-hydroxybutyrate)-co-hydroxyvalerate (PHBV) with 10% of GS particles, previously submitted or not to subcritical water extraction at 170 °C and 180 °C, were obtained by melt blending and characterized. The fibres were better integrated in the PHBV matrix than in PBS, while other molecular compounds from the fillers were released to the polymer matrix, allowing for their antioxidant action. Fillers promoted the stiffness of PBS films (11–44%), reducing their resistance to break and extensibility by 25%, without significant changes in polymer crystallinity or thermal stability. However, this reduced the crystallinity (13%) and thermal stability of PHBV films, decreasing their rigidity (55%). All fibres promoted the oxygen barrier capacity in composites (by about 20–35% for PBS and PHBV, respectively) while also providing them with UV light blocking effects. This barrier effect enhanced the ability of the films to preserve sunflower oil against oxidation, while in PHBV composites, the migration of antioxidant compounds was also detected. No remarkable differences in the effects of the different GS fillers on the properties of composites were detected. Full article

Microplastics (MPs) (<5 mm) are recognized as an emerging global problem in all oceans and coastlines around the world. This paper provided the quantification and characteristics of microplastics found on fourteen beaches along the northwestern Moroccan Mediterranean coast. A total of 42 samples were gathered at a depth of 5 cm along the shoreline using a quadrant of 1 m × 1 m. Microplastics were detected in all sediment samples. The average abundance was 59.33 ± 34.38 MPs kg⁻¹ of dry weight (median: 48.33 MPs kg⁻¹), ranging from 22 ± 7.21 to 135.33 ± 38.80 MPs kg⁻¹. Statistical analyses revealed significant differences between sampling sites. All observed microplastics were classified according to their shape, color, and size. The microplastic shapes comprised fibrous MPs (77.61%), fragments (15.65%), films (4.49%), foams (1.85%), and pellets (0.40%). Microplastic particles in the sediment samples ranged from 0.063 to 5 mm in length and were composed of small (54.3%, <1 mm) and large sizes (45.7%, 1–5 mm). The size fractions with the greatest percentage of MPs were 1–2 mm (24.9%). The dominant color of the microplastics was transparent (43.2%), followed by black (15.8%) and blue (13.3%), with shapes that were mainly angular and irregular. The present results indicate a moderate level of microplastic contamination on the beaches throughout the northern Moroccan Mediterranean coast, and tourism, fishing activities, and wastewater discharges as the most relevant sources. Full article

Vegetal sources are a continuous research field and different types of extracts have been obtained over time. The most challenging part is compounding them in a pharmaceutical product. This study aimed to integrate a mixture (EX) of four extracts (SE-Sophorae flos, GE-Ginkgo bilobae folium, ME-Meliloti herba, CE-Calendulae flos) in formulations with polymers (polyhydroxybutyrate, polylactic-co-glycolic acid) and their physicochemical profiling. The resulting samples consist of particle suspensions, which were subjected to Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy analysis. When compared to single-extract formulations spectra, they revealed band changes, depending on the complex interactions. Using X-ray Diffractometry, the partially crystalline phase was highlighted for EX-PLGA, while the others were amorphous. Moreover, Atomic Force Microscopy pointed out the nanoscale particles and the topography of the samples, and the outstanding roughness belonging to EX-PHB-PLGA. A 30 min period of immersion was enough for the formulations to spread on the surface of the compression stockings material (CS) and after drying, it became a polymeric film. TGA analysis was performed, which evaluated the impregnated content: 5.9% CS-EX-PHB, 6.4% CS-EX-PLGA, and 7.5% CS-EX-PHB-PLGA. In conclusion, the extract’s phytochemicals and the interactions established with the polymers or with the other extracts from the mixture have a significant impact on the physicochemical properties of the obtained formulations, which are particularly important in pharmaceutical product development. Full article

This study aims to investigate the wear and corrosion–wear behavior of 17-4PH stainless steel specimens, both fabricated via Selective Laser Melting (SLM) and conventional bulk material, after undergoing Solution Treatment (S.T.) in a seawater medium. Microstructural observations indicated that solution treatment contributed to a more uniform distribution of martensitic structures on the sample surface. Moreover, the solution-treated specimens exhibited improved microstructural uniformity and structural stability. SLM specimens exhibit the elimination of fine particles and scanning track traces. Based on the results of dynamic polarization tests, SLM specimens demonstrate superior corrosion resistance. However, in corrosion–wear conditions, the bulk material outperforms the SLM specimens, primarily due to the presence of pores in the latter, which are detrimental under such environments. XPS analysis of the passive film structure indicates that the passive layer is mainly composed of FeO, Cr₂O₃, and NiO, with the inner layer predominantly consisting of chromium oxide. The Cr₂O₃ layer, formed by the reaction between chromium and oxygen, significantly enhances the corrosion resistance of the material due to its extremely low chemical reactivity and high stability. Full article

In this paper, we investigated fractal cluster structures of colloidal particles in tin dioxide films obtained from lyophilic film-forming systems SnCl₄/EtOH/NH₄OH with different pH levels. It was revealed that at the ratio Sn > Cl₂ > O₂, N₂ = 0, and pH = 1.42, the growth of cross-shaped and flower-shaped structures of various sizes from several μm to tens of μm is observed. At the ratio Cl₂ > Sn > O₂ > N₂ and pH = 1.44, triangular and hexagonal structures are observed, the sizes of which are on the order of several tens of micrometers. The growth of hexagonal structures is probably affected by the presence of nitrogen in the film, according to the elemental analysis data. At the ratio Sn > Cl₂ > O₂ > N₂ and solution pH of 1.49, the growth of hexagonal and cross-shaped structures is observed, whereas flower-shaped structures are not observed. Hierarchical flower-like and cross-shaped structures are fractal. The shape of microstructures is directly related to the shape of the elementary cells of SnO₂ and NH₄Cl. A direct dependence of the formation of hierarchical structures on the volume of ammonium hydroxide additive was found. This allows for controlling the shape and size of the synthesized structures when changing the ratio of the initial precursors and influencing the final physicochemical characteristics of the obtained samples. Full article

To probe the properties of single atoms is a challenging task, especially from the experimental standpoint, due to sensitivity limits. Nevertheless, it is sometimes possible to achieve this by making corresponding choices and adjustments to the experimental technique and sample under investigation. In the present case, the absolute value of the electronic charge the Fe atoms acquire when they are adsorbed on the surface of aluminum oxide α-Al₂O₃(0001) was measured by a set of surface-sensitive techniques: low-energy ion scattering (LEIS), Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), and work function (WF) measurements, in combination with density functional theory (DFT) calculations. The main focus was the submonolayer coverage of Fe atoms in situ deposited on the well-ordered stoichiometric α-Al₂O₃(0001) 7 nm thick film formed on a Mo(110) crystal face. An analysis of the evolution of the Fe LVV Auger triplet upon variation of the Fe coverage shows that there is electronic charge transfer from Fe to alumina and that its value gradually decreases as the Fe coverage grows. The same trend is also predicted by the DFT results. Extrapolation of the experimental Fe charge value versus coverage plot yields an estimated value of a single Fe atom adsorbed on α-Al₂O₃(0001) of 0.98e (electron charge units), which is in reasonable agreement with the calculated value (+1.15e). The knowledge of this value and the possibility of its adjustment may be important points for the development and tuning of modern sub-nanometer-scale technologies of diverse applied relevance and can contribute to a more complete justification and selection of the corresponding theoretical models. Full article

A traditional SAW (surface acoustic wave) atomizer directly supplies liquid to the surface of the atomized chip through a paper strip located in the path of the acoustic beam, resulting in irregular distribution of the liquid film, which generates an aerosol with an uneven particle size distribution and poor directional controllability, and a high heating phenomenon that can easily break the chip in the atomization process. This paper presents a novel atomization method: a paper strip located at the edge of the atomizer (PSLEA), which forms a micron-sized narrow liquid film at the junction of the atomization chip edge and the paper strip under the effect of acoustic wetting. By using this method, physical separation of the atomized aerosol and jetting droplets can be achieved at the initial stage of atomizer startup, and an ideal aerosol plume with no jetting of large droplets, a uniform particle size distribution, a vertical and stable atomization direction, and good convergence of the aerosol beam can be quickly formed. Furthermore, the effects of the input power, and different paper strips and liquid supply methods on the atomization performance, as well as the heating generation capacity of the liquid in the atomization zone during the atomization process were explored through a large number of experiments, which highlighted the advantages of PSLEA atomization. The experiments demonstrated that the maximum atomization rate under the PSLEA atomization mode reached 2.6 mL/min initially, and the maximum thermal stress was 45% lower compared with that in the traditional mode. Additionally, a portable handheld atomizer with stable atomization performance and a median aerosol particle size of 3.95 μm was designed based on the proposed PSLEA atomization method, showing the great potential of SAW atomizers in treating respiratory diseases. Full article

Synthetic opal-based photonic materials with tunable optical properties not only exhibit significant application potential but also provide valuable models in terms of understanding color formation mechanisms in natural gemstones. Inspired by natural fire opals containing small amounts of Fe₂O₃ nanoparticle inclusions (0 wt%~0.23 wt%), we fabricated short-range ordered opal films doped with low concentrations (0 wt%~2.00 wt%) of Fe₂O₃@SiO₂ core–shell nanoparticles using a modified vertical deposition method. The Fe₂O₃@SiO₂ nanoparticles were synthesized via a sol–gel process to encapsulate the Fe₂O₃ core with a 10-nm-thick SiO₂ shell, preventing agglomeration and enhancing the chemical stability. Experimental results show that even small amounts of doping significantly affect the reflection peak intensity of the films, leading to notable color appearance changes. Combined with numerical simulations, we attribute this modulation to both light absorption and backward scattering effects introduced by the doped nanoparticles. Moreover, the numerical simulation results for Fe₂O₃ nanoparticles and Fe₂O₃@SiO₂ nanoparticles (with a 10 nm silica shell and similar particle size) show comparable optical properties, suggesting that such inclusions may contribute similarly to the color formation mechanisms in natural fire opals. This work demonstrates that low-concentration Fe₂O₃@SiO₂ NP doping provides an effective strategy to tune the color appearance of opal films, with implications for both structural color material development and gemological research. Full article

Aerospace engines ingest small particles when operating in a particulate-rich environment, such as sandstorms, atmospheric pollution, and volcanic ash clouds. These micron particles enter their cooling channels, leading to film-cooling hole blockage and thus thermal damage to turbine blades made of nickel-based single-crystal superalloy materials. This work studied the collision and deposition mechanisms between the micron particles and structure surface. A combined theoretical and numerical study was conducted to investigate the effect of deposits on particle collision and deposition. Finite element models of deposits with flat and rough surfaces were generated and analyzed for comparison. The results show that the normal restitution coefficient is much lower when a micron particle impacts a deposit compared to that of particle collisions with DD3 nickel-based single-crystal wall surfaces. The critical deposition velocity of a micron particle is much higher for particle–deposit collisions than for particle–wall collision. The critical deposition velocity decreases with the increase in particle size. When micron particles deposit on the wall surface of the structure, early-stage particle–wall collision becomes particle–deposit collision when the height of the deposits is greater than twice the particle diameter. For contact between particles and rough surface deposits, surfaces with a shorter correlation length, representing a higher density of asperities and a steeper surface, have a much longer contact time but a lower contact area. The coefficient of restitution of the particle reduces as the surface roughness of the deposits increase. The characteristic length of the roughness has little effect on the rebounding rotation velocity of the particle. Full article

Silicon-doped tetrahedral amorphous carbon (ta-C:Si) coatings are promising materials for achieving ultralow friction in water-lubricated environments, attributed to the formation of Si(OH)_x-based tribofilms. However, the deposition process via filtered cathodic vacuum arc (FCVA) often introduces large particles into the film, increasing surface roughness and causing accelerated wear during the initial sliding phase, despite the high hardness of the coating. In this study, ball-on-disk tribological tests were performed to investigate the wear behavior of ta-C:Si coatings under water lubrication. Friction coefficients, wear volume, and surface roughness were analyzed over various sliding durations. The Archard wear equation and the plasticity index were used to analyze wear and contact behavior. The friction coefficient decreased from 0.14 to 0.04 within the initial 100 m section, and the surface roughness of ta-C:Si decreased sharply from 0.35 μm to 0.01 μm based on the Rpk parameter during 10 h. Following this period, the plasticity index decreased from an initial value of 1.1 to below 0.6, transitioning to a fully elastic contact stage, marking the onset of steady-state wear after 10 h. These results indicate that the reduction in surface roughness plays a crucial role in stabilizing wear behavior and provide insights into optimizing the long-term performance of ta-C:Si coatings in aqueous environments. Full article

Inverted organic light-emitting devices (OLEDs) have been attracting considerable attention due to their advantages such as high stability, low image sticking, and low operating stress in display applications. To address the charge imbalance that has been known as a critical issue of the inverted OLEDs, Li-doped MgZnO nanoparticles were synthesized as an electron-injection layer of the inverted OLEDs. Hexagonal wurtzite-structured Li-doped MgZnO nanoparticles were synthesized at room temperature via a solution precipitation method using LiCl, magnesium acetate tetrahydrate, zinc acetate dihydrate, and tetramethylammonium hydroxide pentahydrate. The Mg concentration was fixed at 10%, while the Li concentration was varied up to 15%. The average particle size decreased with Li doping, exhibiting the particle sizes of 3.6, 3.0, and 2.7 nm for the MgZnO, 10% and 15% Li-doped MgZnO nanoparticles, respectively. The band gap, conduction band minimum and valence band maximum energy levels, and the visible emission spectrum of the Li-doped MgZnO nanoparticles were investigated. The surface roughness and electrical conduction properties of the Li-doped MgZnO nanoparticle films were also analyzed. The inverted phosphorescent OLEDs with Li-doped MgZnO nanoparticles exhibited higher external quantum efficiency (EQE) due to better charge balance resulting from suppressed electron conduction, compared to the undoped MgZnO nanoparticle devices. The maximum EQE of 21.7% was achieved in the 15% Li-doped MgZnO nanoparticle devices. Full article

Climate crisis in the Mediterranean region has severely affected olive tree cultivation, especially due to the long, dry summers, when temperature often rises above 40 °C. In order to overcome such climate challenges in the olive sector, the particle film technology (PFT) was used, as an environmentally friendly alleviation technique, due mainly to the reflecting properties of clay materials. Three clay materials—attapulgite, talc, and kaolin—were applied foliarly to olive trees (both rainfed and irrigated) in July and August. At harvest, yield and oil production per tree were assessed, alongside olive oil quality and functional properties. Under irrigated conditions, trees treated with kaolin or talc in July exhibited the highest yields, whereas under rainfed conditions, trees treated with attapulgite in August, followed by those treated with talc in August, showed the greatest yields. Oil production exceeded that of controls in rainfed trees across nearly all clay treatments. Oils from irrigated trees treated with talc in August and rainfed trees treated with talc in July exhibited high phenolic content, though antioxidant capacity peaked in oils from trees treated with talc in August. These oils, along with those from trees treated with attapulgite in August, contained the highest concentrations of hydroxytyrosol and oleacein. In rainfed trees, most clay treatments resulted in oils with elevated oleic acid (C18:1) and reduced linoleic acid levels, yielding a high monounsaturated-to-polyunsaturated fatty acid ratio. In irrigated groves, August applications produced oils with distinct differences from controls, whereas in rainfed conditions, these differences were evident regardless of application timing. Clay materials offer a promising approach for mitigating abiotic stress under Mediterranean summer conditions; however, further research is needed to elucidate their mechanisms of action. This study represents the first report of foliar attapulgite application in plants and talc application in olive trees. Full article