Ultrasonic Treatment Research Articles

Ultrasonic‐assisted enhancement of malt characteristics in amaranth: A study on physicochemical, amino acid, sugar profile, rheological properties, and muffin making

AbstractBackground and ObjectiveThis study aimed to assess the potential of incorporating ultrasonication treatment into the soaking process before germination as a method to enhance the nutritional profile of amaranth. While ultrasound has been used to expedite germination in various grains, its impact on germinated grains from a food science perspective remains underexplored. The research focused on the effects of ultrasonication on the composition, functional, and rheological properties of amaranth grains post‐germination.FindingsThe study revealed that germination alone significantly increased γ‐aminobutyric acid (GABA), protein content, phenolic acids, amino acids, and total dietary fiber while reducing phytic acid and rheological parameters. Incorporating ultrasonication during soaking further elevated amino acids, GABA, protein, and phenolic acid levels. Notably, ultrasonication increased protein content by 25%, antioxidants by 35%, and dietary fiber by 20%, and attributed to cell wall breakdown and enhanced enzymatic activity during germination. Phytic acid levels decreased by up to 95% with prolonged ultrasonication, enhancing nutritional quality. Additionally, GABA levels revealed a significant rise, with an 82% and 87% increase in the Annapurna and Durga varieties, respectively. The study also found that ultrasonication led to reduced starch content, decreased pasting properties, and increased sugar content in the grains. Muffins made with ultrasonicated amaranth showed lower water activity levels, indicating better shelf stability, though specific volume decreased due to starch breakdown and increased amylase activity.ConclusionThe study demonstrates that ultrasonication combined with germination is an effective method for enhancing the nutritional and functional properties of amaranth grains. This method significantly boosts health‐promoting components like GABA, proteins, and antioxidants while also affecting key baking quality parameters.Significance and NoveltyThis research introduces a novel application of ultrasonication to improve the physiochemical, antioxidant, functional, and rheological properties of amaranth grains. The findings suggested a promising strategy for developing nutrient‐rich, functional food ingredients, addressing the growing demand for healthier food products.

Experimental study of the effects of the ultrasonic peening treatment on residual stress, surface hardness, and hardness depth of parts cut with wire EDM

Experimental study of the effects of the ultrasonic peening treatment on residual stress, surface hardness, and hardness depth of parts cut with wire EDM

Ultrasonic Treatment of Soybean Protein Isolate: Unveiling the Mechanisms for Gel Functional Improvement and Application in Chiba Tofu

Ultrasonic Treatment of Soybean Protein Isolate: Unveiling the Mechanisms for Gel Functional Improvement and Application in Chiba Tofu

Emulsion Structural Remodeling in Milk and Its Gelling Products: A Review.

The fat covered by fat globule membrane is scattered in a water phase rich in lactose and milky protein, forming the original emulsion structure of milk. In order to develop low-fat milk products with good performance or dairy products with nutritional reinforcement, the original emulsion structure of milk can be restructured. According to the type of lipid and emulsion structure in milk, the remolded emulsion structure can be divided into three types: restructured single emulsion structure, mixed emulsion structure, and double emulsion structure. The restructured single emulsion structure refers to the introduction of another kind of lipid to skim milk, and the mixed emulsion structure refers to adding another type of oil or oil-in-water (O/W) emulsion to milk containing certain levels of milk fat, whose final emulsion structure is still O/W emulsion. In contrast, the double emulsion structure of milk is a more complicated structural remodeling method, which is usually performed by introducing W/O emulsion into skim milk (W2) to obtain milk containing (water-in-oil-in-water) W1/O/W2 emulsion structure in order to encapsulate more diverse nutrients. Causal statistical analysis was used in this review, based on previous studies on remodeling the emulsion structures in milk and its gelling products. In addition, some common processing technologies (including heat treatment, high-pressure treatment, homogenization, ultrasonic treatment, micro-fluidization, freezing and membrane emulsification) may also have a certain impact on the microstructure and properties of milk and its gelling products with four different emulsion structures. These processing technologies can change the size of the dispersed phase of milk, the composition and structure of the interfacial layer, and the composition and morphology of the aqueous phase substance, so as to regulate the shelf-life, stability, and sensory properties of the final milk products. This research on the restructuring of the emulsion structure of milk is not only a cutting-edge topic in the field of food science, but also a powerful driving force in promoting the transformation and upgrading of the dairy industry to achieve high-quality and multi-functional dairy products, in order to meet the diversified needs of consumers for health and taste.

Ni mesh-reinforced ultrasonic-assisted Cu/Sn58Bi/Cu joint performance: Experiments and first-principles calculations

The Ni mesh was incorporated into the Cu/Sn58Bi/Cu bonding as a reinforcing skeleton to achieve an enhancement effect analogous to steel reinforcement in concrete. Ultrasonic-assisted soldering (UAS) improved the metallurgical bond among the solder, Ni mesh, and substrate. It facilitated the formation of (Cu, Ni)6Sn5 intermetallic compounds (IMCs) layers, increasing the joint strength. Observations indicated that ultrasonic treatment effectively refined the (Cu, Ni)6Sn5 grains and induced a uniform preferred orientation of β-Sn and Bi grains in the joint matrix adjacent to the Ni mesh. The shear strength of the joint reached 72.23 MPa when the ultrasonic application was sustained for 15 s, achieving the fabrication of a high-strength point with low energy consumption. First-principles calculations have confirmed that changes in the Ni content within (Cu, Ni)6Sn5 IMCs improved the stability of the crystal structure. Furthermore, the variations in content could potentially improve the mechanical and electrical properties of the (Cu, Ni)6Sn5. Enhancements in ultrasonic efficiency and the reinforcement of IMC structures offer new avenues for research in green and high-performance electronic packaging material joining technologies.

Effect of sand content on adhesion and cohesion of municipal sludge during drying practices: The characteristics and modification

Stickiness is a phenomenon observed widely in sludge drying practices, which negatively impacts the sludge drying efficiency. This paper was aimed at evaluating the stickiness characteristics of sludge when the sand content of sludge increases during the rainy season, and carrying out stickiness modification experiments on high sand content sludge. The results indicated that the sand content was significantly positively correlated with the stickiness of sludge. During drying process, the adhesion force and cohesion force of sludge decreased with the increase of drying temperature, and the adhesion force was consistently greater than the cohesion force in every group. The sludge stickiness was reduced after ultrasonic treatment and calcium oxide modification, but the reduction effect of sodium dodecyl sulfate on sludge stickiness was not good. This study confirmed the effect of sand content on sludge stickiness, and the stickiness of sludge with high sand content can be reduced by modifier. These findings contribute to our understanding of the stickiness of sludge with high sand content in the rainy season and provide valuable insights for the optimization of sludge drying process.

Chrysin Nano Formulation Using Cellulose of Rumex vesicarius Herb Leaf Waste: Isolation, Characterization and in-Vitro Evaluation

In this work, for the first time to our knowledge, cellulose was isolated from the Rumex vesicarius herb leaf waste, and cellulose nanospheres (CNS) were developed from this cellulose. Alkali, bleaching, acid hydrolysis, and ultrasonication treatments were used for fabrication of the CNS. The resulting CNS were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), zeta potential and thermogravimetric analysis (TGA). CNS is considered as an effective nanocarrier to alleviate the problems of some drugs like instability, low water solubility and bioavailability. We used the CNS as an effective nanocarrier for the entrapment of chrysin (CHR), a flavonoid secondary metabolite of the flavone class. By adjusting the solvent composition ratio and processing method, the CHR was entrapped in the CNS and a CNS-CHR nano-formulation was developed. An entrapment efficiency of 88.11% was achieved. FTIR, TGA, XRD and TEM confirmed the entrapment of the CHR in the CNS. The in-vitro dissolution investigation demonstrated an 86.53% release of CHR from the CNS-CHR complex when subjected to a release study and 47.14% of CHR release after 24 h, as the pure CHR is poorly soluble in its pure form. These findings indicate that CNS is a highly effective natural carrier at the nanoscale for CHR owing to easy availability and cost-effectiveness.

Tailoring of Ultrasmall NiMnO3 Nanoparticles: Optimizing Synthesis Conditions and Solvent Effects

Nickel manganese oxide (NiMnO3) combines magnetic and dielectric properties, making it a promising material for sensor and supercapacitor applications, as well as for catalytic water splitting. The efficiency of its utilization is notably influenced by particle size. In this study, we investigate the influence of thermal treatment parameters on the phase composition of products from alkali co-precipitation of nickel and manganese (II) ions and identify optimal conditions for synthesizing phase-pure nickel manganese oxide. Ultrafine nanoparticles of NiMnO3 (with sizes as small as 2 nm) are obtained via liquid-phase ultrasonic dispersion, exhibiting a narrow size distribution. A systematic exploration of the solvent nature (water, N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide) on the efficiency of ultrasonic dispersion of NiMnO3 nanoparticles is provided. It is demonstrated that particle size is influenced not only by absorbed acoustic power, dependent on the physical properties of the used solvent (boiling temperature, gas solubility, viscosity, density) but also by the chemical stability of the solvent under prolonged ultrasonic treatment. Our findings provide insights for designing ultrasonic treatment protocols for nanoparticle dispersions with tailored particle sizes.

Optimization and Preparation of Ultrasound-Treated Whey Protein Isolate Pickering Emulsions.

This study aimed to create Pickering emulsions with varying oil fractions and assess the impact of ultrasonic treatment on the properties of Whey Protein Isolates (WPIs). At 640 W for 30 min, ultrasound reduced WPI aggregate size, raised zeta potential, and improved foaming, emulsifying, and water-holding capacities. FTIR analysis showed structural changes, while fluorescence and hydrophobicity increased, indicating tertiary structure alterations. This suggests that sonication efficiently modifies WPI functionality. Under ideal conditions, φ = 80 emulsions were most stable, with no foaming or phase separation. Laser scanning revealed well-organized emulsions at φ = 80. This study provides a reference for modifying and utilizing WPI.

The Role of Methods for Applying Cucurbit[6]uril to Hydroxyapatite for the Morphological Tuning of Its Surface in the Process of Obtaining Composite Materials

In this work, composite materials were obtained for the first time using various methods and the dependences of the resulting surface morphologies were investigated. This involves modifying the surface with cucurbit[n]urils, which are highly promising macrocyclic compounds. The process includes applying cucurbit[6]uril to the hydroxyapatite surface in water using different modification techniques. The first method involved precipitating a dispersion of CB[6] in undissolved form in water. The second method involved using fully dissolved CB[6] in deionized water, after which the composite materials were dried to constant weight. The third method involved several steps: first, CB[6] was dissolved in deionized water, then, upon heating, a dispersion of CB[6] was formed on the surface of HA. The fourth method involved using ultrasonic treatment. All four methods yielded materials with different surface morphologies, which were studied and characterized using techniques such as infrared (IR) spectroscopy and scanning electron microscopy (SEM). Based on these results, it is possible to vary the properties and surface morphology of the obtained materials. Depending on the method of applying CB[6] to the surface and inside the HA scaffold, it is possible to adjust the composition and structure of the target composite materials. The methods for applying CB[6] to the hydroxyapatite surface enhance its versatility and compatibility with the body’s environment, which is crucial for developing new functional composite materials. This includes leveraging supramolecular systems based on the CB[n] family. The obtained results can be used to model the processes of obtaining biocomposite materials, as well as to predict the properties of future materials with biological activity.

The Application of Ultrasound Pre-Treatment in Low-Temperature Synthesis of Zinc Oxide Nanorods

Zinc oxide, due to its unique physicochemical properties, including dual piezoelectric and semiconductive ones, demonstrates a high application potential in various fields, with a particular focus on nanotechnology. Among ZnO nanoforms, nanorods are gaining particular interest. Due to their ability to efficiently transport charge carriers and photoelectric properties, they demonstrate significant potential in energy storage and conversion, as well as photovoltaics. They can be prepared via various methods; however, most of them require large energy inputs, long reaction times, or high-cost equipment. Hence, new methods of ZnO nanorod fabrication are currently being sought out. In this paper, an ultrasound-supported synthesis of ZnO nanorods with zinc acetate as a zinc precursor has been described. The fabrication of nanorods included the treatment of the precursor solution with ultrasounds, wherein various sonication times were employed to verify the impact of the sonication process on the effectiveness of ZnO nanorod synthesis and the sizes of the obtained nanostructures. The morphology of the obtained ZnO nanorods was imaged via a scanning electron microscope (SEM) analysis, while the particle size distribution within the precursor suspensions was determined by means of dynamic light scattering (DLS). Additionally, the dynamic viscosity of precursor suspensions was also verified. It was demonstrated that ultrasounds positively affect ZnO nanorod synthesis, yielding longer nanostructures through even reactant distribution. Longer nanorods were obtained as a result of short sonication (1–3 min), wherein prolonged treatment with ultrasounds (4–5 min) resulted in obtaining shorter nanorods. Importantly, the application of ultrasounds increased particle homogeneity within the precursor suspension by disintegrating particle agglomerates. Moreover, it was demonstrated that ultrasonic treatment reduces the dynamic viscosity of precursor suspension, facilitating faster particle diffusion and promoting a more uniform growth of longer ZnO nanorods. Hence, it can be concluded that ultrasounds constitute a promising solution in obtaining homogeneous ZnO nanorods, which is in line with the principles of green chemistry.

Preparation and slow-release properties of nanocellulose composite hydrogels

Nanocellulose (CNF) was obtained from carrots using a combination of chemical treatment, mechanical milling, and ultrasonic treatment. Ultrafast preparation of maleic anhydride esterified nanocellulose was achieved by a hydrated hydrogen ion-driven dissociation, chemical cross-linking strategy based on a “one-pot” reaction method. Esterification modification with maleic anhydride reduced the crystallinity of nanocellulose and enhanced its thermal stability. High-strength drug-carrying hydrogels (MACNF/SA) with different drug loading capacities were prepared using cefixime (CFX) as a drug model and maleic anhydride esterified nanocellulose (MACNF) and sodium alginate (SA) as the main raw materials. The compressive strength of MACNF/SA hydrogels made from MACNF reached a maximum of 80.3 kPa when the mass ratio of CNF to MA was 2.5:12. Rheological property tests showed that the MACNF/SA hydrogels were pseudoplastic fluids with shear thinning. The drug release from the drug-carrying hydrogels followed non-Fickian diffusion.

Quantitative and Weight Indicators of African Catfish Eggs and Larvae Development under Exposure to the Low-Power Ultrasound

Introduction. The growth of the world population and changing climate conditions on the planet induce the search for the innovative methods and technologies capable to increase the productivity and efficiency of the agricultural sector, and in particular — industrial fish-farming. In recent years, ultrasound has become one of such methods, widely used in many industries due to its unique properties and capabilities. In fish-farming, the use of ultrasound can significantly improve the processes of fish breeding by increasing the growth rate, improving digestion and overall health of fish, however, the issue of biostimulation of eggs and larvae with low-power ultrasound remains unexplored. The aim of this work is to study the biostimulation of eggs and larvae of African (clarias) catfish with ultrasound in aquariums as an advanced method of improving the growth and survival of this biological object at the early stages of its development, as well as a potential method for preventing the infectious and invasive diseases.Materials and Methods. The object of this study is an African clarias catfish, also known as the marbled clarias catfish (Clarias gariepinus). During the experiment, carried out at the fish-farm the “Marbled Catfish” Fish Farm” LLC (Lipetsk) from March to September 2023, 4 groups were formed — three experimental and one control. The eggs and larvae of the African catfish were exposed to the low-power ultrasound, in the experimental groups the exposure lasted for 30 s, 60 s and 120 s, respectively; the control group didn’t undergo any ultrasonic treatment. Biostimulation was carried out with a low-power submersible source of ultrasonic waves (0.243 W/cm2) and was performed 6 times. Sorting was carried out on the 15-th day from the start of incubation. In total, four series of experiment were carried out.Results. The first, second and third groups in all series of the experiment, according to sorting results, contained the largesized larvae of the African catfish in a percentage ratio of 44 to 46%; the percentage of the large-sized larvae in the control group was 19%. In terms of average-size, sorting gave the following result: in 1–3 experimental groups — from 52 to 54% of the total number of larvae; in the control one — 72%. For small-sized larvae, the following values were obtained: in groups 1–3 — from 2 to 3%, in the control group — 9% of the total number of larvae in the groups and series, respectively.Discussion and Conclusion. The growth and development of African catfish eggs and larvae are greatly influenced by the hydrological parameters of water: temperature, oxygenation, illumination, pH, hardness, content of hydrocarbonates, phosphates, nitrates and other chemical elements. In addition, fertilization of eggs may occur unevenly due to non-uniform mixing of eggs and milt, quality and maturity of eggs during fertilization, which can result in different quantitates of the catfish larvae output. The exposure of eggs and larvae to the ultrasound in the experiment resulted in an increase of a number of large-sized larvae, which is favourable for obtaining the fish seed material. Timely sorting of fish seed material before transferring an African catfish to the closed water supply systems reduces the cannibalism during further cultivation. The use of ultrasound in fish-farming requires further study to identify the optimal frequency of treatment and the effect on the commercial fish immunity and growth rate, which will foster the satisfaction of the growing needs of the population in the high-quality products of fishing industry.

Optimizing professional oral hygiene tactics with various methods and tools: impact on microcirculation in periodontal tissues

Relevance. While professional oral hygiene (POH) is widely implemented in dental practice, there is a notable lack of comprehensive research on its effects on periodontal tissues. This underscores the need to investigate the impact of various air-polishing systems (APS) on periodontal tissues in specific clinical contexts. Choosing the appropriate active ingredient in mouth rinses for antiseptic treatment during the final stage of professional oral hygiene is critical for dental practitioners, as the active ingredient directly affects microcirculation in periodontal tissues.Materials and methods. A standard dental examination was conducted on 200 patients aged 18 to 25 years. Patients were divided into groups based on the active component of the APS: calcium carbonate, sodium bicarbonate, a mixture of calcium carbonate and sodium bicarbonate, trehalose, or glycine. In the second stage of the study, antiseptic treatment was performed according to the active ingredient in the mouth rinse, using one of the following antiseptics: chlorhexidine (0.20%) with hyaluronic acid; a combination of clove and fennel essential oils, bromelain enzyme, and bifidobacterium lysate; or essential oil-based rinses containing thymol, eucalyptol, menthol, and methyl salicylate. The control group used distilled water. Microcirculation dynamics in the periodontal tissues were monitored throughout the study using ultrasound Doppler flowmetry.Results. An increase in microcirculation parameters in periodontal tissues was observed following professional oral hygiene using various APS components, both with and without ultrasonic treatment. The application of mouth rinses as the final step in antiseptic oral care contributed to the restoration of microcirculation in periodontal tissues within 1 hour of use.Conclusion. The study identified the most effective protocol for mouth rinse application, tailored to the active component of the air-polishing system.

Ultrasonic-Assisted Marine Antifouling Strategy on Gel-like Epoxy Primer

Ultrasonic technology has drawn extensive interests for its great potential in marine antifouling applications. However, its effects on the adhesion behavior of marine fouling organisms on marine structures remain underexplored. This work investigated how ultrasonic treatment impacted the adhesion of Pseudoalteromonas on a gel-like marine epoxy primer. And the process parameters for ultrasonic treatment were optimized using response surface analysis with Design-Expert software 11. The results revealed that ultrasonic treatment disrupted the cellular structure of Pseudoalteromonas, causing the deformation and fragmentation of the cell membrane, leading to bacterial death. Additionally, ultrasonic treatment reduced the particle size and Zeta potential value of Pseudoalteromonas, which disrupted the stability of bacterial suspensions. It also increased the relative surface hydrophobicity of Pseudoalteromonas cells, resulting in a reduction in adhesion to the gel-like marine epoxy primer. This study demonstrated that ultrasonic treatment significantly disturbed the adhesion behavior of microorganisms like Pseudoalteromonas on the gel-like marine epoxy primer, which provided an effective approach for controlling marine biofouling.

Efficacy of graphene nanocomposites for air disinfection in dental clinics: A randomized controlled study.

Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination. To investigate the use of graphene material for air disinfection in dental clinics by leveraging its adsorption and antibacterial properties. Patients who received ultrasonic cleaning at our hospital from April 2023 to April 2024. They were randomly assigned to three groups (n = 20 each): Graphene nanocomposite material suction group (Group A), ordinary filter suction group (Group B), and no air suction device group (Group C). The air quality and air colony count in the clinic rooms were assessed before, during, and after the procedure. Additionally, bacterial colony counts were obtained from the air outlets of the suction devices and the filter screens in Groups A and B. Before ultrasonic cleaning, no significant differences in air quality PM2.5 and colony counts were observed among the three groups. However, significant differences in air quality PM2.5 and colony counts were noted among the three groups during ultrasonic cleaning and after ultrasonic treatment. Additionally, the number of colonies on the exhaust port of the suction device and the surface of the filter were significantly lower in Group A than in Group B (P = 0.000 and P = 0.000, respectively). Graphene nanocomposites can effectively sterilize the air in dental clinics by exerting their antimicrobial effects and may be used to reduce secondary pollution.

Improving complexation of puerarin with kudzu starch by various ultrasonic pretreatment: Interaction mechanism analysis

The industrial preparation of kudzu starch (KS) significantly reduces the remaining of flavonoids like puerarin (PU) in the product, weakening its biological activity and making pre-treatments on kudzu crucial. Ultrasonic technique, widely used for modifying biomolecules, can enhance nutrient interactions like those between starch and polyphenols in foods. Thus, a puerarin-kudzu starch (PKS) complex was prepared with the introduction of ultrasonic pretreatment. The results indicated that sonication increased the binding of PU to KS from 0.399 ± 0.01 to 0.609 ± 0.05 mg/g. Particle size analysis and SEM revealed that the particles of the ultrasonic puerarin-kudzu starch complex (UPKS) were larger than those of the untreated complexes. XRD, UV–vis, and FT-IR spectroscopic analyses indicated that hydrogen bonding primarily governs the interaction between PU and KS. Additionally, incorporating PU decreased the starch structure’s orderliness, while ultrasonic treatment altered the helical configuration of straight-chain starch, leading to the formation of a new, ordered structure through the creation of new hydrogen bonds. Additionally, gels formed from UPKS exhibited higher viscosity, elasticity, and shear stress, suggesting that ultrasound significantly altered the intermolecular interactions between PKS. In conclusion, the use of ultrasound under optimal conditions has demonstrated its effectiveness in preparing PKS complexes, highlighting its significant potential to produce high value-added kudzu-based products.

Influence of mycelial integrity damaged by ultrasonic treatment on product textural properties and in vitro digestibility

This study investigated the effects of ultrasonic treatment with different intensities (200, 400, and 600 W) and durations (15, 30, and 45 min) on the mycelial integrity, product quality, and in-vitro digestibility of mycoprotein. Results showed that the mycelium was damaged to varying degrees under different ultrasonic parameters. The mycelium showed obvious damage when the time of ultrasonic treatment lasted more than 30 min or the power exceeded 400 W. As a result, the particle size, hardness and chewiness of mycoprotein products were decreased significantly. Compared with the control group (CK), ultrasonic treatment increased the proportion of immobile water and changed the secondary structure of the fungal intracellular protein, which may be the reason for improving in-vitro digestibility of mycoprotein products. This result demonstrated that, by damaging the mycelial integrity and changing the protein secondary structure, ultrasound treatment could decrease the texture characteristics, but improve the water-holding capacity and in-vitro digestibility of products. This study would provide a potential application for the minced meat products by mycoprotein treated with ultrasound.

Application of machine learning in ultrasonic pretreatment of sewage sludge: Prediction and optimization

In this research, typical industrial scenarios were analyzed optimized by machine learning algorithms, which fills the gap of massive data and industrial requirements in ultrasonic sludge treatment. Principal component analysis showed that the ultrasonic density and ultrasonic time were positively correlated with soluble chemical oxygen demand (SCOD), total nitrogen (TN), and total phosphorus (TP). Within five machine learning models, the best model for SCOD prediction was XG-boost (R2 = 0.855), while RF was the best for TN and TP (R2 = 0.974 and 0.957, respectively). In addition, SHAP indicated that the importance feature for SCOD, TN, and TP was ultrasonic time, and sludge concentration, respectively. Finally, the typical industrial scenario of ultrasonic pretreatment of sludge was analyzed. In the secondary sludge, treatment volume at 0.6 L, the pH at 7.0, and the ultrasonic time at 20 min was best to improve the SCOD. In the ultrasonic pretreatment primary sludge, treatment volume of 0.3 L, pH of 7.0, and ultrasonic time of 15 min was best to improve the SCOD. Furthermore, the ultrasonic power at 700 W and ultrasonic time at 20 min were best to improve the C/N and C/P in the secondary sludge. In the primary sludge, the ultrasonic power at 600 W, and the ultrasonic time at 15 min were best to improve C/N and C/P. This study lays a foundation for the practical application of ultrasonic pretreatment of sludge and provides basic information for typical industrial scenarios.

Ultrasound-assisted fabrication of chitosan-hydroxypropyl methylcellulose nanoemulsions loaded with thymol and cinnamaldehyde: Physicochemical properties, stability, and antifungal activity

This study investigated the influence of chitosan (CH) and hydroxypropyl methylcellulose (H), along with ultrasound power, on the physicochemical properties, antifungal activity, and stability of oil-in-water (O/W) nanoemulsions containing thymol and cinnamaldehyde in a 7:3 (v/v) ratio. Eight O/W formulations were prepared using CH, H, and a 1:1 (v/v) blend of CH and H, both with and without ultrasonication (U). Compared to untreated samples, U-treated nanoemulsions had lower droplet sizes (433–301 nm), polydispersity index (0.42–0.47), and zeta potential (−0.42–0.77 mV). The U treatment decreased L* and b* values, increased a* color attribute values, and increased apparent viscosity (0.26–2.17) at the same shear rate. After 28 days, microbiological testing of nanoemulsions treated with U showed counts below the detection limits (< 2 log CFU mL−1). The U-treated nanoemulsions exhibited stronger antifungal effects against R. stolonifer, with the NE/CH-U and NE/CH-H-U formulations demonstrating the lowest minimum inhibitory and fungicidal concentrations, measured at 0.12 and 0.24 μL/mL, respectively. On day 28, U-treated nanoemulsions demonstrated higher ionic, thermal, and physical stability than untreated samples. These findings suggest that the stability and antifungal efficacy of polysaccharide-based nanoemulsions may be improved by ultrasonic treatment. This study paves the way for innovative, highly stable nanoemulsions.