Search Results (229)

The development of materials based on chitosan and polyesters that possess thermoplastic, biocompatible, and biodegradable properties is a perspective for additive technologies in biomedicine. Research on obtaining such compositions is constrained because the polysaccharide content does not exceed 5 wt.%, which cannot ensure effective tissue regeneration. Herein, we propose a method for obtaining thermoplastic block copolymers based on chitosan and poly(ε-caprolactone) by ultrasonic irradiation of a homogeneous solution of a homopolymer mixture in dimethyl sulfoxide as a common solvent, achieving a yield of 99%. The distinctive feature of the method is the interaction between the components at the molecular level and provides obtaining copolymers at any component ratio. SEM images revealed a homogeneous structure without structural defects in both solvent-cast films and extruded filaments. The block copolymers were characterized by high mechanical property tensile strength of up to 60–70 MPa and elasticity of up to 35% for films and 25–40 MPa and elasticity of up to 50% for filaments. Cell adhesion of composition investigated on fibroblast cells (hTERT BJ-5TA) is at the level of chitosan and demonstrated the absence of cytotoxicity. Full article

Single-walled carbon nanotube (SWCNT) inks were prepared by mixing SWCNTs with ethanol and varying the amplitude of ultrasonic dispersion. When the SWCNT inks were prepared by dispersion amplitudes at 60% (nominal value of 200 W), the SWCNT inks had low viscosity and a small variation of the particle size. The SWCNT films fabricated under this dispersion condition had well-distributed SWCNT bundles and exhibited the highest power factor. However, when the dispersion amplitude was excessive, the viscosity of the SWCNT ink increased due to the reduced contact between the SWCNTs owing to over-dispersion, and the crystallinity of the SWCNT films decreased, exhibiting a lower power factor. When the optimized SWCNT films at 60% were applied to heat-source-free water-floating SWCNT-TEGs, an output voltage of 2.0 mV could be generated under sunlight irradiation. These findings are useful for preparing various electronic devices with SWCNT films to improve the film quality using ultrasonic dispersion. Full article

This study presents the synthesis and antidiabetic and hematopoietic activity of ionic compounds based on 2-(diphenylmethoxy)-N,N-dimethylethanamine (diphenhydramine). Synthesis is carried out under ultrasonic (US) and microwave (MW) irradiation as well as using a conventional method (thermal activation). The synthesized ionic compounds have been tested for antidiabetic effect according to the inhibitory action against α-glucosidase and α-amylase (in vitro). All the synthesized derivatives of diphenhydramine showed higher inhibitory activity against α-glucosidase than commercially available diphenhydramine hydrochloride. Moreover, two of them, 1m (66.9%) and 1k (64.2%), had a greater inhibitory activity than the reference drug acarbose (51.8%). The hematopoietic activity was studied in albino laboratory female rats (in vivo). The compounds 1b, 1f, and 1k can restore immune blood cells (hematopoietic activity), equal to or exceeding that of the commercially available diphenhydramine hydrochloride and control (methyluracil). Full article

An efficient protocol has been developed for the synthesis of a new bioactive sulfonylphthalimide under environmentally friendly conditions. Ultrasonic energy was used to achieve the desired products with excellent yields and high purity, all in solvent-free conditions. The synthesis of this sulfonylphthalimide was carried out using sulfamide and phthalic anhydride. The structure of the synthesized compound was confirmed by 1H, 13C NMR and MS spectral data as well as IR spectroscopy. Full article

The propagation of high-frequency ultrasound waves will generate both physical and chemical effects as they propagate through a liquid medium, such as acoustic streaming, an acoustic fountain, and atomization. These phenomena are believed to be the main factors that contribute to the enhancement of mass transfer in the gas–liquid carbon dioxide (CO₂) absorption system. Computational Fluid Dynamic (CFD) simulation is one of the powerful tools that can be used to model the complex hydrodynamic behavior induced by the propagation of ultrasound waves in the liquid medium. In this study, the ultrasonic irradiation forces were simulated via the momentum source term method using commercial CFD software (ANSYS Fluent V19.1). In addition, a parametric study was conducted to investigate the influences of absorber height and ultrasonic power on the hydrodynamic mixing performance. The simulation results indicated that enhanced mixing and a higher intensification factor were achieved with increased fountain flow velocity, particularly at the lowest absorber height and highest ultrasonic power. Conversely, the energy efficiency was improved with the increase of absorber height and decrease of ultrasonic power. To determine the optimal combination of absorber height and ultrasonic power, this trade-off between the energy efficiency and intensification in the ultrasonic-assisted absorption system (UAAS) is a crucial consideration during process scale-up. Full article

Bacillus thuringiensis is widely utilized as a microbial insecticide due to its production of parasporal crystals during the spore-forming stage. However, lower fermentation efficiency coupled with elevated production costs limit its broad application. Low-frequency ultrasound (LFU) has been employed in the fermentation industry to enhance microbial growth and metabolism. In this study, the effect of LFU on the growth of B. thuringiensis HD1 and the yields of parasporal crystals was investigated. The maximum biomass accumulation of Bacillus thuringiensis and parasporal crystal production yield were achieved following low-frequency ultrasonic (LFU) treatment applied during the logarithmic growth phase (18 h of cultivation) under optimized parameters: a frequency of 40 kHz, a power output of 176 W, and an irradiation duration of 45 min. Under optimal conditions, LFU significantly increased the cell membrane permeability and secretory inositol, favoring cell growth and parasporal crystal production. FESEM/CLSM and TEM analyses visually displayed the changes in cell morphology. In addition, the germination rate of spores was increased after LFU treatment, which further confirmed the positive effect of LFU on the growth of B. thuringiensis. Compared to the control, parasporal crystals harvested under LFU exhibited significant modifications in their physicochemical characteristics; the particle size increased, the surface electronegativity intensified, and there was a morphological transition from spherical to cubic geometry. Importantly, the parasporal crystals exhibited strong insecticidal activity against S. zeamais adults, a typical stored-product insect pest, with an LC₅₀ of 10.795 mg/g on day 14 and a Kt₅₀ of 4.855 days at a concentration of 30 mg/g. These findings will provide new insights into the product development and application of B. thuringiensis in the future. Full article

The High-Intensity Heavy-Ion Accelerator Facility (HIAF) is a significant national science and technology infrastructure project, constructed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). It is designed to provide intense proton, heavy ion beams, and target-produced radioactive ion beams for nuclear physics and related research. Large-aperture, high-precision, room-temperature, and superconducting dipole magnets are extensively used to achieve high-intensity beams. However, for large-scale magnets (particularly superconducting magnets), the traditional Hall probe mapping measurement platform encounters several limitations: a long preparation time, high cost, low testing efficiency, and positional inaccuracies caused by repeated magnet disassembly. This paper presents a new magnetic field mapping measurement system incorporating ultrasonic motors operable in strong magnetic fields (≥7 T), enabling portable, highly efficient, and high-precision magnetic field measurements. After system integration and commissioning, the prototype dipole magnet for the high-precision spectrometer ring (SRing) was measured. The measurement system demonstrated superior accuracy and efficiency compared with traditional Hall probe mapping systems. On this basis, the magnetic field distribution and integral excitation curve of all 11 warm-iron superconducting dipole magnets and 3 anti-irradiation dipole magnets in the HIAF fragment separator (HFRS) were measured. Each magnet took less than 1 day to measure, and all magnetic field measurement results met the physical specifications. Full article

This study describes the efficient synthesis of five dinitrochalcones (DNCHs) using an ultrasonic bath as an unconventional method to improve reaction yields and reduce reaction times. The Claisen–Schmidt condensation of nitroacetophenones and nitrobenzaldehydes was carried out in a cyclohexane–methanol solvent system under ultrasonic irradiation, achieving yields between 56% and 92%. The application of ultrasound not only accelerated the reaction but also improved the overall efficiency compared to conventional methods such as magnetic stirring. The synthesized compounds were characterized by NMR spectroscopy, which corroborated their structures. Therefore, it is confirmed that obtaining DNCHs with a nitro group in ortho by ultrasonic irradiation is an energetically efficient and environmentally friendly alternative. Full article

Pollution of soil by heavy metals has become a critical environmental issue. This study investigated an innovative approach to heavy metals removal, focusing on the desorption of nickel and zinc from vermiculite using a combination of leaching and ultrasonic (US) irradiation at 20 or 362 kHz. When 0.1 M HCl was used as a washing solution, Zn²⁺ desorption yields around 85% were obtained in all conditions. Under 20 kHz US, fragmentation of the particles occurred, leading to the formation of new sites where released Zn²⁺ could sorb, allowing improved decontamination by cation exchange. Even higher yields were obtained with the biobased citric acid. Ni²⁺ desorption yields were lower due to its distribution in less accessible Tessier fractions. They significantly increased under US, especially at 362 kHz. It is shown that US leads to transfer of the contaminant from less accessible fractions (in particular the residual one) to more accessible ones, and that at low frequency, new sorption sites are created by fragmentation, leading to readsorption in the exchangeable fraction. This study brought to light for the first time the potential of high-frequency US in enhancing soil washing, to a higher extent compared to low-frequency (20–50 kHz) US. Full article

This study presents an innovative approach to processing refractory zinc-bearing clinker through the synergistic application of microwave thermal treatment and ultrasonic-assisted leaching. Microwave irradiation induces phase transformations in the clinker, improving its reactivity and facilitating subsequent zinc dissolution, while ultrasonic cavitation enhances mass transfer by disrupting passivation layers. Key process parameters, including acid concentration, temperature, pulp density, and leaching time, were systematically investigated using response surface methodology (RSM) and central composite design (CCD). The results demonstrate that the optimized process conditions led to a significant increase in zinc recovery from refractory materials. Full article

This work investigates the optimization of aniline content in polyaniline (PANI)/sago starch blends prepared via in situ oxidative polymerization under ultrasonic irradiation. Building upon our previous optimizations of pH and sonication time, this study focuses on the effect of aniline concentration (5–65 wt%) on electrical conductivity, morphological dispersion, and thermal stability. Various characterization techniques, including field emission scanning electron microscopy (FE-SEM), ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FT–IR) spectroscopy, and thermogravimetric analysis (TGA), confirm that a well-connected, conductive network forms at about 35 wt% aniline. Electrical conductivity measurements reveal a pronounced rise from ~1.6 × 10⁻⁸ to ~2.2 × 10⁻³ S/cm between 5 wt% and 35 wt% aniline. Conductivity stabilizes above this threshold due to PANI agglomeration. Morphological assessments confirm a shift from smooth, uniform blends at low aniline to rougher, void-filled surfaces when aniline exceeds 50 wt%. TGA shows improved thermal stability with increasing aniline content. These findings highlight an optimum aniline loading of ~35 wt% to achieve synergy between conductivity and structural integrity in biopolymer-based PANI/sago starch composites, offering a pathway to sustainable, high-performance biopolymer-based conductors for applications in sensors, flexible electronics, and electromagnetic shielding. Full article

This study presents a novel method combining photoelectrochemical etching with ultrasonic vibration for the formation of nanocrystalline porous silicon (NC-PS). This combined process enhances the band gap energy absorption (BEA) by reducing bubble accumulation in the etching area. It is found that laser irradiation can decrease the etching rate, while ultrasonic vibration aids with bubble expulsion, preventing accumulation in the etching area, resulting in more uniform etching and increasing the porosity of the porous silicon (PS). High porosity in NC-PS structures enhances the surface area, thereby increasing electron mobility and improving the electron energy distribution. Our experiments demonstrate that this combined process leads to more uniform and deeper etching and the creation of well-defined porous structures. The more uniform PS size distribution (8–14 nm) achieved by photoelectrochemical etching combined with ultrasonic vibration enhances the optical properties of the material due to quantum confinement effects. Porosity measurements provide essential surface characterization information that is crucial for determining the performance of PS diode components in various applications. Our findings demonstrate that this combination technique improves the uniformity, efficiency, and precision of porous silicon etching, producing material for high-performance applications, including sensors, catalysts, and photonic devices. Full article

In this paper, a method of ultrasound-assisted low-pressure closed acid digestion followed by inductively coupled plasma mass spectrometry (ICP-MS) analysis was proposed for trace element quantification in rock samples. By using 1.5 mL of a binary acid mixture of HNO₃–HF with a ratio of 2:1, rock powder samples of 50 mg were completely decomposed in 12 h at 140 °C after 4 h of ultrasonic treatment with or without pressure relief procedure. The element extraction efficiency of this method was evaluated via the yielded relative errors (REs) of the trace elements in a series of geological standard reference materials (SRMs) with compositions from basic to acidic. It was found that the contents of trace elements (i.e., 36 metal elements from Li to U) in basalt BCR-2, diabase W-2a, andesite AGV-2, granodiorite GSP-2, and granite GSR-1 were comparable with the reported reference values, giving REs with absolute values less than 10%. It was also found that clear solutions without sample powder residues by naked-eye observation can be obtained when using the low-pressure closed decomposition method without ultrasonic pretreatment. The quantification results, however, were found to be negatively biased for most of the studied trace elements, and, in particular, the content bias of Zr in SRM GSP-2 was down to −86.28% due to the low extraction efficiency of refractory minerals of the low-pressure closed digestion method. By applying this proposed digestion strategy, the decomposition property of the ternary combination of HNO₃–HF–mannitol in terms of trace element quantification accuracy was also investigated. Results showed that the concentrations of trace elements in the studied SRMs were consistent with the reference values, giving REs within ±6.94%, which revealed that there was no deterioration of extraction efficiencies of trace elements and neglected mass interferences from mannitol. This study demonstrated the essential role of ultrasound irradiation in rock sample decomposition to achieve the high extraction efficiency of trace elements under a low-pressure environment, and the developed approach with promising future applications in geoscience exhibited considerable merits, including a high extraction efficiency, feasible digestion process, less time consumption, and lower safety associated risks. Full article

The peculiarities of the crystal formation from supersaturated aqueous solutions of CuSO₄ on polymer substrates were studied using X-ray diffractometry. During the crystal formation, the test solutions were irradiated with one or two counter-propagating ultrasonic beams. Test solutions were prepared using natural deionized water with a deuterium content of 157 ± 1 ppm. The other liquid used was deuterium-depleted water with a deuterium content of 3 ppm. It was shown that irradiation with one/two ultrasonic beams resulted in drastic changes in the structure of the crystal deposit formed on the polymer substrate in the case when natural deionized water was chosen for preparing the supersaturated solution of CuSO₄. Full article

Glycerol is a major by-product in biodiesel manufacturing, which accounts for around 10% of the biodiesel volume. A surplus of glycerol has led to the development of technologies for production of value-added products using glycerol as a raw material, following the “waste as a resource” strategy. Various techniques are available to carry out glycerol transformation, viz. carrying out processes under thermal heating, application of ultrasonic or hydrodynamic cavitation, microchannel technologies, etc. Microwave-assisted organic synthesis (MAOS) is a simple and innovative technology, which can be considered as a means of intensifying these processes. This review describes microwave irradiation as a valuable energy-efficient alternative to conventional heating for the production of value-added chemicals from glycerol via dehydration, hydrogenolysis, esterification, transesterification, etherification, and oxidation. In general, innovative and potential catalysts, approaches, and technologies are discussed and critically evaluated in terms of the possibilities and potential for further industrial implementation Full article