Search Results (574)

The Dual Fluid Reactor (DFR) is a Generation IV concept that relies on a phased development pathway using a low-temperature microdemonstrator ($\mu$DEMO) and a high-temperature minidemonstrator (mDEMO). A rigorous methodology is required to scale experimental data between these facilities to ensure the reliable design of the final reactor. This paper establishes such a methodology grounded in Similarity Theory. The Cathare-2 system code was used to perform a parametric study on a simplified model of the demonstrators, which use lead–bismuth eutectic and pure liquid lead, respectively. This study focused on identifying the specific operating conditions required to match key “defining” dimensionless numbers—the Reynolds number (Re) for dynamic similarity and the Peclet number (Pe${}_h$) for thermal similarity. The analysis successfully identified and presented the distinct operating ranges of fluid velocity and mass flow required to achieve either state. Results show that matching the Reynolds number allows for the dimensionless pressure drop to be scaled with a deviation below 0.2%, while matching the Peclet number allows for the dimensionless temperature profile to be scaled with a deviation under 2.5%. The central finding is that dynamic and thermal similarity cannot be achieved simultaneously due to the different working fluids and temperatures of the demonstrators. This forces a strategic choice in experimental design, where an experiment must be tailored to investigate either fluid dynamics or heat transfer. This work provides the foundational “rulebook” for designing these crucial experiments, ensuring that data from the DFR demonstrator program is both reliable and scalable. Full article

We present a systematic machine learning study of the solubility of diverse pharmaceutical acids in deep eutectic solvents (DESs). Using an automated Dual-Objective Optimization with Iterative feature pruning (DOO-IT) framework, we analyze a solubility dataset compiled from the literature for ten pharmaceutically important carboxylic acids and augment it with new measurements for mefenamic and niflumic acids in choline chloride- and menthol-based DESs, yielding N = 1020 data points. The data-driven multi-criterion measure is applied for final model selection among all collected accurate and parsimonious models. This three-step procedure enables extensive exploration of the model’s hyperspace and effective selection of models fulfilling notable accuracy, simplicity, and also persistency of the descriptors selected during model development. The dual-solution landscape clarifies the trade-off between complexity and cost in QSPR for DES systems and shows that physically meaningful energetic descriptors can replace or enhance explicit COSMO-RS predictions depending on the application. Full article

Copper is a critical resource for the energy transition and the development of novel sustainable processes for its recovery must be a focus of research. The use of deep eutectic solvents (DES) is an alternative for the solvometallurgical extraction of copper from sulfide ores with low or zero water consumption. The objective of this research is to study the dissolution of low-grade copper sulfide ore (0.83% Cu) using deep eutectic solvents. Laboratory scale agitation leaching tests were performed using different DES based on choline chloride (ChCl), namely ChCl-ethylene glycol, ChCl-citric acid, and ChCl-urea, at different temperatures (25, 50, and 60 °C). The effect of water and hydrogen peroxide was also studied in some systems. The best copper extractions were achieved with ChCl-citric acid > ChCl-urea > ChCl-ethylene glycol, reaching ≈99% copper extraction in some cases. This mineral leaching process offers an alternative to the processing of sulfide minerals and could be a technique that allows the use of solvent extraction and electrodeposition facilities available at a metallurgical plant, with less water consumption than the traditional leaching process. Full article

The recovery of rare earth elements (REEs) from the spent NdFeB magnets has great strategic significance for ensuring the security of critical mineral resources. This process requires scientifically designed separation technologies to ensure high output and purity of the obtained rare earths. Hydrometallurgy has been widely applied to extract REEs from spent permanent magnets. This paper summarizes and reviews hydrometallurgical technologies, mechanisms, and applications for the separation and recovery of REEs and iron (Fe) from the spent permanent magnets. Key methods include: The hydrochloric acid total solution method, where the spent NdFeB is completely dissolved in hydrochloric acid, iron is precipitated and removed, and then REEs are extracted. The hydrochloric acid preferential dissolution method, where spent NdFeB magnets are first fully oxidized by oxidative roasting, converting Fe²⁺ to Fe³⁺, which hydrolyzes to Fe(OH)₃, and is precipitated and removed, allowing for the subsequent extraction of REEs to obtain rare earth oxides. Acid baking and water leaching, where spent NdFeB is calcined with acidification reagents, and the calcined products are dissolved in water to leach out REEs. At the same time, Fe is retained in the leaching residue. Electrolysis in aqueous solution, where Fe is electrolyzed at the anode or deposited at the cathode to separate it from REES. Organic acids leaching, where organic acids dissolve metals through acidolysis and complexation. Bioleaching, which utilizes microorganisms to recover metal through biological oxidation and complexation. Ionic liquid systems, where Fe or REEs are extracted using ionic liquid or leached by deep eutectic solvents. This paper provides an in-depth discussion on the challenges, advantages, and disadvantages of these strategies for recycling spent NdFeB magnets, as well as the leaching and extraction behavior of REEs. It focuses on environmental impact assessment, improving recovery efficiency, and decreasing reagent consumption. The future development direction for recycling spent NdFeB magnets is proposed, and a research idea of proposing a combined process to avoid the drawbacks of a single recycling method is introduced. Full article

A new and transformative era in semiconductor packaging is underway, wherein, there is a shift from transistor scaling to system scaling and integration through advanced packaging. For advanced packaging, interconnect scaling is a key driver, with interconnect density requirements for chip-to-substrate microbump pitch below 5 μm and half-line pitch below 1 μm for Cu redistribution layer (RDL). Here, we present a comprehensive theoretical comparison of thermal cycling behavior in accordance with JESD22-A104D standard, intermetallic thickness evolution, and steady-state thermal analysis of Cu-microbump assembly for different bonding materials and substrates. Bonding materials studied include solder caps such as SAC105 (Sn98.5Ag1.0Cu0.5), eutectic Sn-Pb (Sn63Pb37), eutectic Sn-Bi (Sn42Bi58), Pb95Sn5, Indium, and Cu-Cu TCB structure. Effect of substrates including Si, glass and FR-4 is evaluated for various microbump structures with varying pitches (85 µm, 40 µm, 10 µm, and 5 µm) on their fatigue life. Results indicate that for Cu-microbump assemblies at an 85 µm pitch. The Pb95Sn5 exhibits the longest predicted fatigue life (3267 cycles by Engelmaier and 452 cycles by Darveaux), while SAC105 shows the shortest (320 and 103 cycles). Additionally, the Cu-Cu TCB structure achieves an estimated lifetime of approximately 7800 cycles, which is significantly higher than all solder-based Cu-microbump assemblies. The findings contribute to advanced packaging applications by providing valuable theoretical references for optimizing solder materials and structural configurations. Full article

Liquid metal embrittlement (LME) occurs when a normally ductile alloy undergoes brittle fracture in contact with a liquid metal. The mechanisms behind LME remain unclear, and most of the models rely on post mortem analyses. In this work, we overcome this limitation by performing in situ scanning electron microscopy (SEM) notched micro-bending tests on α-brasses exposed to the gallium–indium eutectic (EGaIn) at room temperature, enabling real-time correlation between load–displacement curves and crack evolution during LME. In the Cu-30%Zn alloy, LME was observed only after prior plastic deformation and ductile crack growth, confirming that liquid metal did not influence early plasticity. A two-step experiment further showed that a pre-existing crack in contact with EGaIn, under continued loading, was sufficient to trigger brittle fracture. The Cu-20%Zn alloy displayed alternating ductile and brittle events, with brittle cracks propagating horizontally before arresting in undeformed zones, leading to stepped load–displacement curves. By contrast, pure Cu and Cu-15%Zn showed only ductile fracture despite continuous contact with EGaIn. These results demonstrate that LME in the Cu-Zn/EGaIn system acts during crack propagation rather than initiation. The present in situ SEM methodology provides direct evidence of fracture mechanisms and a framework for future experimental modeling comparisons. Full article

Oleanolic acid (OA)-stabilized water-in-oil Pickering high internal phase emulsions (HIPEs), using natural deep eutectic solvents (NADESs) as the internal phase (HIPE-NADES), were developed to enhance OA bioavailability. Three kinds of NADESs (proline: sorbitol (1:1), proline: glucose (1:1), and proline: glucose (5:3)) were selected, and HIPEs with pure water as the internal phase were used as the control group. In vitro digestion and Caco-2 models showed that HIPE-NADES significantly improved OA bioaccessibility via enhanced stability and solubility. Crucially, OA bioavailability reached 16.20–19.10%, markedly surpassing controls (p ≤ 0.05), indicating that NADESs’ hydrogen-bonding network facilitates intestinal uptake. In a t-BHP-induced Caco-2 oxidative stress model, OA-loaded HIPE-NADES significantly attenuated damage, reducing MDA and ROS while elevating GSH-Px, CAT, and SOD activities and GSH levels (p ≤ 0.05). NADESs themselves contributed substantially to antioxidant efficacy. HIPE-NADESs represent an effective platform for enhancing the bioavailability and bioactivity of hydrophobic phytochemicals like OA, enabling simpler and more stable delivery systems. Full article

Efficiently identifying suitable solvents for active pharmaceutical ingredients (APIs) is critical in drug formulation, yet the vast number of possible solvent-solute combinations presents a significant experimental challenge. This study addresses this by developing a robust machine learning (ML) model for accurately predicting the solubility of three phenolic acids (syringic, p-coumaric, and caffeic) in various deep eutectic solvents (DESs), integrating both experimental and computational investigations. Measured solubility data showed that the choline chloride combined with triethylene glycol in a 1:2 molar ratio was the most efficient system for the dissolution of the studied APIs. Different ML models, utilizing nu-Support Vector Regression (nuSVR) as the core regressor and based on descriptor sets derived from COSMO-RS (Conductor-like Screening Model for Real Solvents) computations, were systematically evaluated. A novel methodology termed DOO-IT (Dual-Objective Optimization with ITerative feature pruning) was employed to address the common challenges of model development with limited, high-value datasets. The final optimal 10-descriptor nuSVR model, selected from an exhaustive, multi-run search, demonstrated outstanding predictive power, offering a highly reliable computational tool for guiding experimental screening, significantly accelerating the exploration of DES-based formulations. This research also provides a strong foundation for future machine learning-guided discovery of chemicals, offering an effective and transferable framework for developing QSPR models for various chemical systems. Full article

Quince (Cydonia oblonga Mill.) processing generates peel and core by-product fractions that are underexploited resources with untapped potential for valorization in sustainable food systems. In this study, ultrasound-assisted extraction was performed using several choline chloride-based natural deep eutectic solvents (NADES, six formulations with distinct hydrogen-bond donors) and compared with 70% (v/v) ethanol. Extracts were analyzed for total phenolic content, antioxidant capacity, and individual phenolic compounds by LC-MS/MS, and their bioaccessibility was determined through a standardized in vitro digestion model. Organic acid-based NADES, particularly ChCl:MA (2:1) and ChCl:LA (1:1), yielded significantly higher phenolic contents from the peel than ethanol (up to ~45% increase, p < 0.05), and ChCl:MA maintained superior antioxidant capacity after digestion. In the core fraction, glucose- and glycerol-based NADES promoted the release of bound phenolics, resulting in bioaccessibility values exceeding 100%, indicating the release of previously bound phenolics under digestive conditions. The present study provides novel insights into the effects of NADES on both extraction efficiency and digestibility of quince by-products. These findings highlight quince peel and core as promising raw materials for developing functional food and nutraceutical ingredients, thereby offering a feasible strategy for upcycling fruit-processing residues into health-promoting applications. Full article

Heterologous protein expression underpins the production of therapeutics, industrial enzymes, and diagnostic reagents, yet persistent challenges remain in enhancing yields, achieving correct folding, and reducing the costs and environmental burdens of downstream processing. Natural Deep Eutectic Solvents (NADESs)—a class of biocompatible, sustainable, and highly tunable solvents—have recently emerged as promising tools to overcome these limitations. This review systematically examines the intersection of recombinant protein production and NADES technology, assessing their applications across the full workflow, from host strain expression to purification and final formulation. Literature analysis highlights the potential of NADESs as media additives that mitigate cellular stress and improve soluble protein yields, as gentle solubilizing and refolding agents for inclusion bodies, as phase-forming components in aqueous two-phase systems for green purification, and as stabilizing excipients for long-term storage. Key constituents such as betaine, proline, urea, and arginine are identified as functional agents whose eutectic mixtures often deliver synergistic benefits that differ mechanistically from the action of the individual components. The integration of NADESs into recombinant protein production offers a path toward more sustainable and economically viable biomanufacturing. Critical gaps remain, including in vivo validation and techno-economic assessment. Future opportunities include high-throughput NADES screening and computational design of application-specific solvents. Full article

The demand for sustainable methods to extract bioactive compounds from native fruits is increasing. We evaluated the potential of natural deep eutectic solvents (NaDES) combined with ultrasound-assisted extraction (UAE) to recover phenolic compounds from Ugni molinae Turcz. (murta), a Chilean fruit with recognized ethnopharmacological and antioxidant value. Seven choline chloride-based NaDESs (M1–M7) were assessed and compared with conventional methanol: formic acid extraction (M8). The choline chloride: 1,2-propanediol system (1:2, M2) achieved the highest recovery of total phenolics (64.87 mg GAE/g) and flavonoids (35.38 mg QE/g), together with strong antioxidant activity (DPPH IC₅₀: 1.05 µg/mL; ORAC: 40,291 µmol TE/g). When comparing the different NaDES formulations (M1–M8), M8 displayed superior FRAP and ORAC values, although its phenolic and flavonoid yields were lower, reflecting differences in solvent selectivity. HPLC-DAD analysis further revealed that NaDES, particularly M5 (choline chloride: oxalic acid, 1:1), favored the extraction of flavonoid and anthocyanin-type compounds. Multivariate and PCA analyses showed distinct chemical profiles in NaDES extracts, forming two clusters apart from M8. Pearson correlation analysis linked antioxidant capacity with major flavonoids. Overall, NaDES combined with UAE represents an efficient, green strategy for selectively recovering bioactives, supporting applications in foods, nutraceuticals, and health products from Chilean native fruits. Full article

A hydrophobic deep eutectic solvent (HDES) composed of Aliquat 336, decanoic acid, and n-hexanol, diluted with kerosene, was investigated for the selective leaching of LiNi_0.33Mn_0.33Co_0.33O₂ (NMC-111) cathode materials. While conventional choline chloride-based DESs co-dissolve Li and transition metals almost completely, the present HDES–acid hybrid system deliberately sacrifices maximum recovery to achieve selectivity. In combination with a low concentration of H₂SO₄, the HDES enabled preferential dissolution of Co and Ni (~84% and ~80% after 6 h at 90 °C, respectively), while Li and Mn largely remained in the solid residue (>93%). Kinetic modeling indicated that the process is controlled by a surface chemical reaction with apparent activation energies of ~~49 kJ mol⁻¹ (for Ni recovery) and ~51 kJ mol⁻¹ (for Co recovery). The leaching residues were enriched in stable Li-Mn-O phases in a way that offers a basis for stepwise recovery. These findings show that hydrophobic eutectic media coupled with mild acid activation provide a sustainable pathway for the selective recycling of LIB cathodes. Full article

Plant-based residues generated within the agri-food system represent an abundant resource with significant potential for sustainable valorization. However, they are still underutilized and place a substantial burden on the environment and climate. This review discusses research trends over the past decade, combining bibliometric analysis with an overview of emerging technologies applied to the processing of residues generated from conventional crops and medicinal and aromatic plants. The bibliometric analysis reveals main valorization pathways, ranging from energy production to recovery of high-value bioactive compounds. Recent advances in this field are discussed in detail, with emphasis on low-energy and non-thermal processing (ultrasound, microwave, cold plasma), green solvents (natural deep eutectic solvents, bio-based solvents), biological pretreatments (with ligninolytic microorganisms and enzymes), thermochemical technologies (hydrothermal carbonization, pyrolysis), and emerging cascade strategies applied for multi-product recovery. Published research proves that these approaches have a great potential for sustainable valorization, while process optimization and economic feasibility remain a challenge at industrial scales for wider adoption. By providing an integrated perspective on diverse types of plant-based residues, this review highlights the importance of developing cascade and circular processing strategies, which align with global sustainability goals and encourage innovation in bio-based industries. New knowledge and advances in this field are highly required and will further help the transition of the current agri-food system towards greater circularity and sustainability. Full article

Significant depletion of natural resources, coupled with increased environmental pollution resulting from the constant evolution of global industrialization, poses a considerable problem. Therefore, it is unsurprising that sustainable “green” chemistry and technology are gathering the worldwide scientific community, whose common goal is to find applicable solutions for the abovementioned problems. This paper combined the ultrasonic extraction method (a form of “green” technology) with natural deep eutectic solvents (NADESs, a type of “green” solvent) for the production of extracts from an industrial by-product (discarded waste wild apple dust). Waste wild apple dust was pretreated with different NADESs in order to explore the pretreatment benefits regarding ultrasonic extraction of bioactive compounds. Among all solvents used, aqueous propylene glycol was chosen as the best system, which, combined with Reline NADES pretreatment, provided the highest TPC and TFC values, together with the best antioxidant activities. UHPLC-DAD-MS analyses of extracts revealed the presence of natural organic acids, quercetin and kaempferol derivatives, tannins, and flavones. Following this procedure, valorization of agro-industrial apple herbal waste resulted in obtaining extracts with high potential for utilization in different industrial branches (food and pharmaceutical industries), contributing to both cleaner production and reduced environmental impact. Full article

Vitis vinifera L. cultivar, “Assyrtiko”, is a famous grape variety native to Santorini island. Its wine production residues are rich in bioactive polyphenols, making them valuable for extraction and use in cosmetics. The aim of this work was the development and optimization of an extraction process from “Assyrtiko” Wine Production Residue (AWPR), using a Natural Deep Eutectic Solvent (NaDES) as the extraction medium. Four NaDESs were synthesized and screened for the extraction, and the extracts were evaluated for Total Phenolic Content (TPC) and Total Flavonoid Content (TFC). The NaDES comprising betaine and 1,3-propanediol was chosen for further analysis because of its effectiveness as an extraction solvent. The extraction process was optimized using a Box–Behnken experimental design. The NaDES %w/w content in the NaDES/water system was found to play the most statistically significant role in the quality of the extracts, assessed via TPC and TFC values. The quality of the extract obtained from the optimal conditions was practically stable with respect to TPC and TFC after long storage, suggesting that NaDESs have a potential “protective” effect for the extracted phytochemicals and give energy-efficient character to the process. This extract was also directly incorporated into a moisturizing cosmetic formulation, which remained homogeneous and stable after testing, demonstrating the extract’s potential for cosmetic applications. Full article