Search Results (2,057)

This study investigates the interface between cement hydration, low-field NMR relaxometry, and the incorporation of carbon-based fillers into cementitious materials. The objective is to provide NMR-based insights into how carbon black (CB) and an acrylic superplasticizer (SP) influence cement hydration and the resulting microstructural evolution. CB was integrated into white Portland cement (WPC) using both wet and dry mixing approaches, with water content and SP dosage varied independently. First, water-based “inks” containing different SP/CB weight ratios were prepared and evaluated through dynamic light scattering (DLS) and ζ-potential measurements to assess colloidal stability and dispersibility. For the wet-mixing route, an in situ NMR experiment was performed to monitor the progressive incorporation of carbon ink into cement pastes while increasing the water content. The ability to distinguish ink-related signals from those originating from the cement paste represents a promising step toward non-destructive assessments of carbon dispersion in fresh pastes. Separately, ex situ NMR measurements were performed on samples extracted from dry-mixed pastes with various SP dosages. These experiments mark the SP-induced delay in hydration and the refinement of the pore network that is also associated with improved particle dispersion. Complementary optical microscopy (OM) and ultrasonic pulse velocity (UPV) measurements on hardened samples corroborate the NMR findings. Full article

The present study evaluates the impact of cavitation on the performance of the chemical refining of rapeseed oils and the enzymatic interesterification of fat blends using a powerful UP400S ultrasonicator (400 W, 20 kHz). Ultrasound-assisted alkali neutralization achieved efficiency comparable to that of the conventional 60 min process in only 7 min, with similar refining losses (5.04–6.80 wt.%), although slightly higher lipid peroxidation was observed. Performing the ultrasound cavitation under a protective nitrogen atmosphere minimized the formation of lipid peroxides and their breakdown products (i.e., hexanal, nonanal), partially protected tocopherols, and improved oxidative stability (IP at 120 °C = 3.9–4.4 h). Ultrasound-assisted enzymatic interesterification (EIE) of palm kernel fat and a palm stearin blend catalyzed by immobilized lipases (Lipozyme TL IM, Lipozyme RM IM, Novozyme 435) was carried out for the first time. Cavitation accelerated triacylglycerol rearrangement, reduced reaction time from 6 h (9.0·10⁻³ to 1.6·10⁻² min⁻¹) to only 1 h (5.5·10⁻² to 1.2·10⁻¹ min⁻¹), and significantly affected melting point stabilization and solid fat content profile. In summary, ultrasound cavitation substantially enhanced mass transfer and reaction kinetics, demonstrating strong potential for process intensification in the edible oil industry. Further optimization of reaction conditions is required before large-scale industrial implementation. Full article

Unmanned aerial vehicles open new possibilities for developing technologies that support more sustainable and efficient agriculture. This paper presents a non-invasive method for repelling rodents from crop fields using ultrasound. The proposed system is implemented as a spherical-cap ultrasound loudspeaker array consisting of eight transducers, mounted on a drone that overflies the field while emitting sound in the 20–70 kHz range. The hardware design includes both the loudspeaker array and a custom printed circuit board hosting power amplifiers and a signal generator tailored to drive multiple ultrasonic transducers. In parallel, a genetic algorithm is used to compute flight paths that maximize coverage and increase the probability of driving rodents away from the protected area. As part of the validation phase, artificial intelligence models for rodent detection using a thermal camera are developed to provide quantitative feedback on system performance. The complete prototype is evaluated through a series of experiments conducted both in controlled laboratory conditions and in the field. Field trials highlight which parts of the concept are already effective and identify open challenges that need to be addressed in future work to move from a research prototype toward a deployable product. Full article

Traditional ultrasonic bolt stress measurement is hindered by high power consumption. Lowering excitation voltage reduces power but degrades signal-to-noise ratio (SNR), compromising accuracy. This paper proposes a synergistic algorithm combining Empirical Mode Decomposition (EMD) with Adaptive Threshold Wavelet Denoising (ATWD). The method preserves transient features by reconstructing high-frequency components via EMD, then suppresses noise by precisely processing low-frequency components using ATWD. Finally, cross-correlation estimates ultrasonic delay. Evaluated at excitation voltages from 12 V to 0.5 V, the EMD-ATWD method maintains measurement errors below 10% even at 0.5 V, improving accuracy by over 48% compared to conventional Finite Impulse Response (FIR) and Threshold Wavelet Denoising (WTD) methods, while enhancing key echo waveform fidelity by over 35%. This method provides a reliable low-power bolt stress monitoring idea for engineering applications. Full article

A novel polysaccharide from Cynanchum auriculatum Royle ex Wight was isolated, structurally characterized, and its antioxidant activity was evaluated. The crude extract was purified by ion exchange and size exclusion chromatography to obtain a homogeneous fraction, CAP2-1. CAP2-1 displayed a weight-average molecular mass of 184.17 kDa and is mainly composed of galactose, arabinose, and galacturonic acid. Structural analysis revealed that CAP2-1 is a highly branched acidic arabinogalactan-type polysaccharide with a backbone of →6)-β-D-Galp-(1→, →3,6)-β-D-Galp-(1→, and →4)-α-D-GalpA-(1→ units, and side chains enriched in α-L-arabino furanose residues. Ultrasonic degradation produced a lower-molecular-weight derivative, UCAP2-1, which exhibited significantly stronger free radical scavenging ability compared with CAP2-1 (p < 0.01). These findings suggest that molecular weight reduction enhances antioxidant properties by improving electron-donating capacity and accessibility to reactive sites. This study reveals the structure–antioxidant relationship of CAP2-1 and UCAP2-1 and highlights UCAP2-1 as a promising natural antioxidant. Full article

Background/Objectives: This study evaluates the penetration of a calcium silicate-based sealer (BC Universal) into dentinal tubules after different final irrigation protocols. Methods: Eighty-four single-rooted extracted teeth were instrumented with ProTaper Gold to size F4 and assigned to four groups (n = 21) according to the final irrigation protocol as follows: conventional needle irrigation (CNI), sonic agitation with EndoActivator (EA), ultrasonic activation (UA), and XP-Endo Finisher (XPF). A total of 20 canals from each group were filled with BC Universal sealer mixed with fluorescein and the single-cone obturation technique. The remaining specimen in each group served as a negative control to assess potential imaging bias. Specimens were sectioned 3 mm from the apex and analyzed under confocal laser scanning microscopy. Sealer penetration was assessed by penetration area (PA), maximum depth (MaxD), mean depth (MeanD), and percentage of canal perimeter infiltrated (P). Data were analyzed using Kruskal–Wallis or ANOVA tests (α = 0.05). Results: All activation/agitation techniques showed significantly higher penetration than CNI across all variables (p < 0.001). No significant differences were found among EA, PUI, and XPF for PA, MaxD, and MeanD. However, XPF exhibited the highest perimeter infiltration, which was significantly greater than EA and UA (p < 0.001). Conclusions: Irrigant activation significantly enhanced dentinal tubule penetration of BC Universal sealer compared to CNI. XPF provided superior P, suggesting superior circumferential distribution. These findings suggest a more effective cleaning of the root canal in the apical third achieved by the tested irrigant activation/agitation techniques, which may improve the sealing potential of BC Universal sealer. Full article

Li₃PO₄ is a promising raw material for the low-cost synthesis of high-performance LiFePO₄. Reactive crystallization from low-concentration lithium-rich brine is a key process for the efficient preparation of high-quality Li₃PO₄ products. The effect of operating conditions (temperature/supersaturation/impurities/ultrasonic) on the induction time was investigated using a focused beam reflectance measurement. The evaluation of the primary nucleation, growth kinetics, and parameters for the extraction of Li₃PO₄ from low-concentration lithium-rich brine was conducted using an induction time method. The dominant mechanisms at different stages were inferred through online monitoring of the particle size distribution during the Li₃PO₄ crystallization process. Results show that induction time decreases with increasing operating conditions (temperature/supersaturation/ultrasonic frequency), indicating that their increases all promote nucleation. Impurities (NaCl/KCl) did not significantly affect the induction time, whereas Na₂SO₄ and Na₂B₄O₇ significantly increased it, with Na₂B₄O₇ showing the most notable effect. Classical nucleation theory was applied to determine kinetic parameters (nucleation activation energy/interfacial tension/contact angle/critical nucleus size/surface entropy factor). Results indicate that Li₃PO₄ mainly nucleates through heterogeneous nucleation, with a temperature increase weakening the role of heterogeneous nucleation. Fitted models indicate that Li₃PO₄ predominantly follows the secondary nucleation and spiral growth mechanism. Our findings are crucial for crystallization design and control in producing high-quality Li₃PO₄ from lithium-rich brines. Full article

Fibrin clots with strain-hardening characteristics exhibit pronounced material nonlinearity and acoustic dispersion under ultrasound, leading to waveform distortion and shock formation during finite-amplitude wave propagation. However, peak-shock stress is limited by viscoelastic dissipation and dispersion, constraining the efficiency of ultrasound in applications such as thrombus ablation. To overcome this limitation, a shock wave amplification method using designed multi-wave-packet sequences is proposed. Based on a power-law model from quasi-static compression tests, shock generation under a single sinusoidal pulse was first simulated. The dual-wave-packet chasing strategy was then developed, in which the amplitude, frequency, and time delay of the second packet were tuned to achieve effective superposition with the precursor. The waveform superposition factor (WSF) was introduced for quantitative evaluation. Numerical results demonstrate that this strategy can significantly increase the peak-shock-wave stress, with a maximum gain of 22.7%. Parametric analysis further identified amplitude as the dominant factor influencing wavefront steepness and amplification effectiveness. This study provides a novel method and theoretical support for developing efficient and controllable ultrasonic sequences for thrombolysis. Full article

Aronia melanocarpa, a plant with nutrient-rich fruits, with application in the food and pharmaceutical industry, has been extensively investigated but, nevertheless, the exploration of the secondary metabolites profile from its by-products remains quite limited. The main objective of this study was to evaluate the possibility of using some different natural mineral waters from Romania, as green solvents, for the extraction of bioactive compounds from aronia stems and fruits by applying eco-compatible working techniques (maceration for 24 h, and ultrasonication at room temperature and 50 °C for 30 min). The effect of five natural mineral waters (one with medium and four with low mineral content) on the extraction capacity and phytochemical profile of stems and fruits’ extracts was monitored using fast and efficient analysis techniques (electrochemical, spectroscopic, and chromatographic) and compared with that of classical solvents. The results showed that, in the case of stems, extraction by maceration was, for all types of water used, the most efficient, followed by ultrasonication at room temperature. Also, at the same time, in most cases, all mineral waters showed better performance than distilled water, and the highest efficiency of the extraction process was recorded for natural water with a medium mineralization level. The similarity observed in the phytochemical profiles of aqueous extracts from the aronia stems and the fruits highlights both the potential of this by-product as a source of bioactive compounds and the efficiency of natural mineral waters as green extraction solvents. Full article

Steel pipes play a vital role in energy and industrial transportation systems, where undetected defects such as cracks and wall thinning may lead to severe safety hazards. Although ultrasonic guided waves enable long-range inspection, their defect imaging performance is often limited by dispersion, multimode interference, and strong noise. In this work, a multi-frequency fusion imaging method integrating time-reversal, topological derivative, and sparse Bayesian learning is proposed for guided wave-based defect detection in steel pipes. Multi-frequency guided waves are employed to enhance defect sensitivity and suppress frequency-dependent ambiguity. Time-reversal focusing is used to concentrate scattered energy at defect locations, while the topological derivative provides a global sensitivity map as physics-guided prior information. These results are further fused within a sparse Bayesian learning framework to achieve probabilistic defect imaging and uncertainty quantification. Dispersion compensation based on the semi-analytical finite element method is introduced to ensure accurate wavefield reconstruction at different frequencies. Domain randomization is also incorporated to improve robustness against uncertainties in material properties, temperature, and measurement noise. Numerical simulation results verify that the proposed method achieves high localization accuracy and significantly outperforms conventional TR-based imaging in terms of resolution, false alarm suppression, and stability. The proposed approach provides a reliable and robust solution for guided wave inspection of steel pipelines and offers strong potential for engineering applications in nondestructive evaluation and structural health monitoring. Full article

The construction sector faces the dual challenge of reducing energy consumption and mitigating the environmental burden of construction and demolition waste (CDW). Geopolymers offer a low-carbon alternative to Portland cement, yet their performance depends strongly on precursor composition. This study presents an extensive investigation of precursor chemistry, mechanical performance and phase composition, focusing on the partial substitution of ground granulated blast furnace slag (GGBFS) with mechanically activated CDW powder (15% and 30% by weight) alongside fly ash (FA). The oxide composition, amorphous content and particle size distribution were analyzed, using XRF, XRD and laser diffraction to evaluate the reactivity. Mortar samples were subsequently synthesized and tested for compressive and flexural strength, ultrasonic pulse velocity, density and porosity. The results demonstrate that while mechanically activated CDW incorporation decreases early strength compared with GGBFS-rich systems, compressive strengths above 45 MPa were attained at 28 days, with continuous improvement to >69 MPa for aged composites. The relationship between precursor chemistry, precursor sizes and mechanical performance highlights the feasibility of CDW valorization in geopolymer binders, contributing to energy efficiency, circular economy strategies and sustainable construction materials. Full article

Pipelines, as critical carriers for energy transportation, are prone to defects such as cracks and corrosion during long-term operation. Traditional testing methods exhibit limitations in various aspects, while electromagnetic ultrasonic testing technology, leveraging its advantages of non-contact operation and couplant-free application, has emerged as a significant direction for pipeline integrity assessment. This paper analyzes the advantages of EMAT guided wave testing technology in achieving long-distance and rapid screening of pipelines, as well as the strengths of bulk wave testing technology in high-precision quantitative evaluation. It also examines the unique value of obliquely incident SV waves in the directional identification of weld defects. Furthermore, the paper discusses the potential of integrating EMAT with multiple technologies, demonstrating how multi-physical field synergy enhances detection reliability. Finally, it summarizes the remaining challenges in practical engineering applications, providing references for advancing the field toward intelligent and high-precision development. Full article

Grape pomace is a major byproduct of winemaking and a rich source of bioactive anthocyanins with potential functional value. This study aimed to optimize anthocyanin extraction from Tannat grape pomace and evaluate its antioxidant and anti-aging activities. Ultrasonic-assisted extraction combined with a Box–Behnken design identified optimal conditions of 51.27 °C, 53.46% ethanol, 20.10 min ultrasonication, and a 1:24.05 solid-to-liquid ratio, yielding 186.21 ± 1.03 mg/100 g (R² = 0.9798, p < 0.0001). Tannat Grape Pomace Anthocyanins showed strong antioxidant capacity, with 2,2-Diphenyl-1-picrylhydrazyl scavenging of 89.44% ± 0.87% at 0.2 mg/mL (IC₅₀ = 0.09 mg/mL) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging of 95.83% ± 0.54% at 0.75 mg/mL (IC₅₀ = 0.26 mg/mL). In Caenorhabditis elegans, TGPA extended lifespan, improved motility, and increased heat and oxidative stress resistance without reducing reproductive capacity. Lifespan is a key indicator of aging. This study holds significant implications for advancing our understanding of the mechanisms underlying lifespan regulation, the connection between aging and disease, as well as the development of anti-aging therapies for humans. In conclusion, these findings indicate that Tannat Grape Pomace Anthocyanins possess promising antioxidant and anti-aging potential and support the sustainable, high-value utilization of grape pomace. This approach directly aligns with the core principles of sustainable agriculture by transforming an agricultural byproduct into a valuable resource. Full article

Background/Objectives: Essential oils (EOs) from plants of the genus Cinnamomum have been widely used based on their antimicrobial, antioxidant, and anti-inflammatory properties. However, their elevated volatility and limited aqueous solubility restrict their use in pharmaceutical and food formulations. Cyclodextrins (CDs) have emerged as a promising strategy to overcome these limitations through the formation of inclusion complexes. Methods: In this study, inclusion complexes of essential oil from C. camphora L. (EOCNM) with β-cyclodextrin (β-CD) were developed using physical mixing (PM), ultrasonic treatment (US), and freeze-drying (FD). The inclusion complexes were physicochemically characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TG/DTG), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to evaluate their physicochemical interactions and complexation efficiency. Results: Our results demonstrated successful complex formation, with the FD and US methods showing greater amorphization and stronger inclusion characteristics compared to the PM method. Thermal analysis confirmed improved physicochemical stability of the essential oil when complexed with β-CD. Furthermore, the cytotoxicity assay of the complexes was assessed using the MTT assay and J774 macrophage cells. The complexes exhibited low cytotoxicity, indicating their potential biocompatibility for biomedical and food applications. Conclusions: Overall, β-CD encapsulation effectively enhanced the physicochemical stability and safety profile of C. camphora essential oil, providing a promising strategy for its controlled delivery and protection against degradation. Full article

Compressed air systems are widely used in industry, and air leaks that occur over time lead to significant and unnecessary energy losses. This study aims to quantify the energy-saving potential of compressed air leaks in a manufacturing plant and to develop machine learning (ML) regression models for sustainable leak management. A total of 230 leak points were identified by measuring three periods using an ultrasonic device. Using the measured acoustic emission level (dB) and probe distance (x) as inputs, the leak flow rate, annual energy-saving potential, cost loss, and carbon footprint were calculated. As a result of the repairs, energy consumption improved by 8% compared to the initial state. Three regression models were compared to predict leak flow: Linear Regression, Bagging Regression Trees, and Multivariate Adaptive Regression Splines. Among the models evaluated, the Bagging Regression Trees model demonstrated the best prediction performance, achieving an R² value of 0.846, a mean squared error (MSE) of 389.85 (L/min²), and a mean absolute error (MAE) of 12.13 L/min in the independent test set. Compared to previous regression-based approaches, the proposed ML method contributes to sustainable production strategies by linking leakage prediction to energy performance indicators. Full article