Search Results (10,026)

In recent years, microwave and ultrasound technology has been under extensive development in drying technologies. Researchers are constantly searching for improved solutions or alternatives to hot air drying. The goal of this work was to determine the intermittent action of ultrasound and microwaves on convective drying. An examination of five specific cases of stationary and nonstationary drying processes was conducted. The evolution of moisture content and drying rate over process time was discussed, and the average drying rate and time, drying constant, effective diffusion coefficient, and specific energy consumption were also compared. To identify the differences between the dried products, the quality characteristics such as: water activity, color, shrinkage, rehydration, polyphenol content, odor, and flavor of apples were analyzed. The results indicate that intermittent drying provides a good alternative to convective drying, including when combined with microwave and ultrasound treatments. Applying microwaves or ultrasound intermittently resulted in an increase in the effective diffusion coefficient (by 68%) and drying rate (by 117%) and a reduction in drying time (by 53%), compared to convective drying. This processing method resulted in lower energy consumption by up to 13% and well-preserved quality attributes—this could be very promising for the production of healthy, ready-to-eat apple snacks. Full article

Microwave Radiation Imagers (MWRIs) onboard the FY-3B, FY-3C, and FY-3D satellites are the primary sensors for sea surface temperature (SST) observation. Benefiting from the resolution of several key calibration issues in brightness temperature products, MWRI SST records spanning more than a decade have been reprocessed. In this study, these reprocessed SST products are evaluated using direct comparison and the extended triple collocation (ETC) method, along with additional error analyses. Compared with iQuam SST, the reprocessed MWRI SST products from the three satellites show total root mean square errors (RMSEs) of 0.80–0.82 °C and total biases of −0.12 °C to 0.00 °C. ETC analyses based on MWRI, ERA5, and Argo SSTs indicate random errors of 0.76–0.78 °C. Furthermore, the reprocessed MWRI SST products demonstrate temporal stability and exhibit minimal crosstalk effects from sea surface wind speed, columnar water vapor, and columnar cloud liquid water in SST retrievals. Compared with previous versions, the reprocessed products show significant improvements, with consistent performance across FY-3B, FY-3C, and FY-3D. However, differences in SST observations due to the varying local times of the ascending nodes among the three satellites should be corrected in practical applications. Full article

Fresh lettuce is a key ingredient in ready-to-eat salads that are considered a valued dietary choice. Lettuce quality is strongly influenced by soil management practices, particularly in sustainable farming systems. This study evaluated the effects of three different soil disinfestation methods (flame weeding, microwave irradiation, and biological control (Trichoderma spp. inoculation) on the quality traits of Lactuca sativa L. var. Margò grown in a protected environment in southern Italy in a winter growth cycle. Minerals, nitrate content, colorimetric parameters, carotenoids, polyphenols, and antioxidant activity were assessed. The treatment with Trichoderma spp. significantly reduced nitrate accumulation (−21.3%) and increased some phenolic compounds and P (22%), while microwave irradiation treatment boosted total phenolic content by 44%. Flame weeding, although partially effective, was associated with a slight increase in carotenoids. Overall, microwave irradiation and Trichoderma spp. treatments emerged as the most promising options for balancing food safety and nutritional value. These findings offer valuable insights about the effect of soil disinfestation strategies on leafy vegetable quality. Full article

The traditional management of resectable colorectal liver metastases (CLMs) includes systemic therapy and curative (R0) surgery. Hepatocellular carcinoma (HCC) treatment options include R0 surgery, liver transplantation (LT), chemoembolisation, and targeted chemotherapy. Ablative techniques (radiofrequency ablation and microwave ablation) targeting liver lesions were until recently considered suitable only for patients deemed unfit for surgical resection. However, over time, data suggesting the non-inferior results of radical (A0) ablation compared with radical surgery have started to emerge. Given the lower complication rate of ablative therapies compared with surgery, the question arises as to whether ablation has the potential to replace the role of surgery in the treatment of HCC and colorectal cancer metastases to the liver. In this review, we address the current evidence on the topic and its possible impact on future clinical practice. Full article

Fecal sludge (FS) requires effective management to mitigate environmental and public health risks and enable resource recovery. This study evaluated the effects of microwave (MW) treatment on FS characteristics and subsequent anaerobic digestion (AD) performance. MW treatment raised FS temperatures to ~96 °C, reducing FS volume by 50% and inducing three thermal phases. Soluble chemical oxygen demand (sCOD) showed a multi-phase pattern, with a maximum solubilization of 29.8% during initial heating due to the solubilization of proteins and carbohydrates. Scanning electron microscopy (SEM) revealed morphological changes, while Fourier transform infrared (FTIR) spectroscopy confirmed that core functional groups remained unchanged. MW-pretreated FS enhanced AD performance, achieving a 17% increase in cumulative methane yield, alongside 18% and 33% improvements in organic loading and methane production rates, respectively. MW treatment influenced the phase distribution of digestate components, showing a shift in nutrient portioning towards the liquid fraction. These results suggest that integrating MW pretreatment into FS management systems can improve energy recovery, reduce treatment costs, and support resource-efficient sanitation solutions. Full article

Microwave (MW) sintering offers a promising alternative to conventional heating in powder metallurgy, providing faster processing, lower energy consumption, and improved microstructural control. In the diamond tool industry—where cost-efficiency and competitiveness are critical—MW–hybrid sintering shows strong potential for producing segments designed for cutting and polishing natural stone and construction materials. This study investigates the effects of sintering temperature, dwell time, and green density on the densification and mechanical properties of metal matrix composite (MMC) segments containing diamond particles. MW sintering reduced the optimum sintering temperature by 90–170 °C when compared to conventional free sintering. Under optimal conditions (57% green density, 820 °C, 5 min dwell), segments achieved ~95% densification and mechanical properties comparable to hot-pressed (HP) samples. Although MW–hybrid sintered matrices exhibited slightly lower Young’s modulus (~15%) and Vickers hardness (~20%), their flexural strength and fracture toughness remained comparable to HP counterparts. Overall, MW hybrid sintering provides a cost-effective, energy-efficient, and scalable route for fabricating high-performance diamond tool segments, supporting both economic viability and sustainable, competitive manufacturing. Full article

To improve the drying efficiency and quality of Scutellaria baicalensis (S. baicalensis) for both medicinal and beverage purposes, this study examined the effects of temperature, vacuum degree, and rotation speed during rotary microwave vacuum drying. The study focused on drying kinetics, physicochemical properties, and sensory quality of the Scutellaria slices. Multivariate analyses, including hierarchical cluster and correlation network analyses, were used to explore the relationship between parameters and quality. Results showed that the method significantly reduced drying time and improved moisture migration. It also preserved active components like baicalin, wogonoside, total phenolics, and polysaccharides, with high antioxidant activity maintained. Temperature was the key factor. The best balance was achieved with 50 °C, −75 kPa, and 4.2 rad/s, resulting in high drying efficiency, a sensory acceptability score of 8.8, turbidity of 12.4 NTU, and strong antioxidant capacity. Cluster analysis distinguished microwave-vacuum-dried samples from those dried by traditional methods (natural air-drying and hot-air drying). Correlation network analysis revealed positive links between sensory acceptance, active components, and liquor clarity. This optimized parameter set is recommended for producing high-quality Scutellaria ingredients for consumers. Full article

Synthetic aperture radar (SAR), as a high-resolution microwave remote sensing imaging technology, plays an indispensable role in both military and civilian applications. However, in complex electromagnetic countermeasure environments, radio frequency interference (RFI) severely degrades SAR imaging quality. SAR anti-interference, as a countermeasure method, has significantly practical values. Although deep learning-based anti-interference techniques have demonstrated notable advantages, two key issues remain unresolved: 1. Strong coupling between interference suppression and SAR imaging—most existing methods rely on raw echo data, leading to a complex processing pipeline and error accumulation. 2. Scarcity of labeled data—the lack of high-quality labeled data severely restricts model deployment. To address these challenges, this work constructs a standardized dataset and conducts comprehensive validation experiments based on this dataset. The main contributions are as follows: Firstly, this work establishes the mathematical model for block-type interference, laying a theoretical foundation for the subsequent construction of RFI-polluted data. Secondly, this work constructs a block-type interference dataset, which includes the labeled data constructed by our laboratory and open-source data from the Sentinel-1 satellites, providing reliable data support for deep learning. Thirdly, this work proposes an image subspace-based interference suppression method, which eliminates the dependence on raw echo data and significantly simplifies the processing pipeline. Finally, this work makes a fair comparison of the current works, summarizes the existing problems, and looks forward to possible future research directions. Full article

This work aims to maximize the Hawking emission temperature arising in the optical analog model of the event horizon of an astrophysical black hole. A weak probe wave interacts with an intense ultrashort optical pulse via the Kerr effect in a photonic crystal fiber. This interaction causes the probe wave to experience an effective spacetime geometry characterized by the presence of an optical event horizon, where the analogous Hawking radiation effect arises. Here we refer to the simulated or classical version of the analog of Hawking radiation. This study considers four distinct types of photonic crystal fibers with anomalous dispersion curves that allow for maximizing the effect. Our first three numerical simulations indicate that a Hawking emission temperature of up to 361 K can be achieved with a photonic crystal fiber with two zero-dispersion wavelengths, while the emission temperature values in the original investigation are lower than 244 K. And in the fourth, we can see that we have a configuration in which the temperature can be improved up to 1027 K. Moreover, these results also emphasize the feasibility of using analog models to test the quantum effects of gravity, such as Hawking radiation produced by typical black holes, whose magnitude is far below the temperature of the cosmic microwave background (2.7 K). Full article

This study presents a lightweight metasurface microwave absorption filter (MMAF) designed for low-frequency stealth applications in the L-band. The metasurface is optimized using a genetic algorithm to achieve broadband absorption at subwavelength thickness. The fabricated MMAF consists of a glass fiber-reinforced plastic layer, a metasurface layer, and a dielectric layer with a size of 30 × 30 cm². It maintains a reflection coefficient below −10 dB in the frequency range of 1.01–1.78 GHz. Experiments using small MMAFs measuring 15 × 15 cm² confirmed stable performance after composite molding. In addition, the results from small MMAFs configured in a 2 × 2 array were similar to those of the 30 × 30 cm² structure. These results highlight the potential of the MMAF for scalable deployment on curved or segmented surfaces, expanding its applicability to various stealth platforms. Full article

The mushroom industry generates a substantial amount of residues each year, encompassing materials such as processing residues and spent substrates. Much of this biomass is discarded, despite its richness in valuable compounds. Mushroom residues contain bioactive substances including β-glucans, phenolic compounds, proteins, and dietary fiber, all of which are well known for their antioxidant and antimicrobial properties. While fruit and vegetable residues have been extensively explored as raw materials for eco-friendly packaging, mushroom-derived residues remain a largely underutilized resource. Recent studies have highlighted their potential as a renewable source of functional ingredients for sustainable food packaging. By applying green extraction technologies such as ultrasound- or microwave-assisted methods, researchers can recover stable bioactive compounds and incorporate them into biodegradable polymers. Early results are promising: packaging films enriched with mushroom residue extracts demonstrate improved mechanical strength, enhanced barrier properties, and added bioactivity. This strategy aligns with the principles of the Circular Economy, simultaneously reducing environmental impact and adding value to materials that were previously discarded. Although further optimization is needed, particularly regarding extraction efficiency, compound stability, and scalability, the valorization of mushroom residues represents a promising pathway toward the next generation of sustainable, eco-friendly packaging materials. Full article

Accurate daily surface soil moisture (SSM) mapping at high spatial resolution (e.g., 30 m) remains challenging due to individual satellite sensor limitations. Although passive microwave sensors provide frequent coarse-resolution observations and synthetic aperture radar (SAR) offers high-resolution data intermittently, achieving both simultaneously requires sensor synergy. This paper introduces the microwave–optical multi-stage synergistic downscaling framework (MMSDF) to generate daily 30 m SSM products. The framework integrates SMAP L4 (9 km), MODIS data (500 m–1 km), harmonized Landsat Sentinel-2 (HLS, 30 m), radiometric terrain corrected Sentinel-1 (RTC-S1, 30 m), and auxiliary geographic data. It comprises three stages: (1) downscaling SMAP L4 to 1 km via random forest; (2) calibrating Sentinel-1 water cloud model (WCM) using intermediate 1 km SSM to retrieve 30 m SSM without in situ calibration; and (3) fusing daily 1 km SSM and intermittent 30 m WCM-derived retrievals using the spatial–temporal fusion model (ESTARFM) to generate seamless daily 30 m SSM maps. Validation against in situ measurements from 16 sites in Hunan Province, China (summer 2024) yielded R of 0.54 and RMSE of 0.045 ${\mathrm{cm}}^3/{\mathrm{cm}}^3$. Results demonstrate the framework’s capability to synergize multi-source data for high-resolution daily SSM estimates valuable for hydrological and agricultural applications. Full article

In this paper, a novel model of dust storm intensity variations and its effects on earth–satellite link design for total attenuation prediction has been developed. The proposed model expresses the total dust-induced attenuation as a function of the empirically derived specific attenuation in (dB/km) and effective slant path distance. The formulation incorporates the vertical variation in dust storm intensity along the propagation path to more accurately represent the attenuation experienced by slant links. The effective slant path distance is obtained as a combination of a total slant path distance and an adjustment factor. The adjustment factor has been developed based on the visibility height model of the dust storm structure. The proposed model has been validated with one-year measured attenuation on 6.2 km and 7.6 km long microwave links operating at 21.2 GHz and 14.5 GHz, respectively. Full article

The name Green Chemistry was coined in 1996 to point out the development of chemical substances and sustainable processes that reduce the formation of toxic products for the environment and humans. The urgent need to bring down the negative effects of the chemical industry to safeguard human health has been the driving force behind green chemistry and the need to respect the United Nations Sustainable Development Goals. This approach allows to increase the effectiveness of synthetic methods, to develop safer, less toxic, and environmentally sustainable chemicals. In this context, microwave-assisted organic reactions revolutionized the chemical synthesis; as a matter of fact, microwave chemistry led to a low environmental impact of the used solvents, and, over the years this overture has become the method of choice in synthetic chemistry. This review highlights in detail the main features of microwaves. Full article

The rising amount of food industry waste has sparked interest in its valorization as a source of bioactive compounds. This study combines bibliometric analysis and a systematic review to map the scientific literature on the recovery of bioactive compounds from food byproducts, focusing on green extraction strategies and their alignment with the principles of the circular economy. A total of 176 documents, published between 2015 and 2025, were analyzed. The analysis shows significant growth after 2020 and highlights bioactive compounds, extraction, and the circular economy as the primary research themes. Italy, Spain, and Brazil emerged as the leading countries in scientific production. The systematic review covers green extraction techniques, including ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), enzyme-assisted extraction (EAE), and natural deep eutectic solvent extraction (NADES). UAE- and NADES-based processes were the most frequently applied extraction techniques, mainly targeting phenolic compounds and flavonoids. Significant progress has been observed, particularly in the advancement of extraction technologies, in the recovery of key bioactive compounds, and in their industrial applications. These methods recover phenolics, flavonoids, anthocyanins, and other compounds with antioxidant, antimicrobial, and cardioprotective properties, which have potential applications in functional foods, nutraceuticals, pharmaceuticals, cosmetics, and biodegradable packaging. Nutraceuticals and functional foods represent the main application areas, followed by cosmetics and pharmaceuticals. Despite progress, challenges remain, including scalability, equipment costs, solvent recovery, and process standardization. The green extraction of bioactive compounds from food byproducts shows promise and can support the goals of the 2030 Agenda. Full article