Search Results (709)

Among the main man-made water pollutants that pose a danger to the environment are oil products, heavy metals, and radionuclides, as well as micro- and nanoplastics. To purify such waters, it is necessary to use advanced methods, with sorption being one of them. The aim of this work is to develop a nano-functionalized composite, comprising magnetically responsive, thermally expanded graphite (TEG) and the natural clay bentonite, and to assess its ability to purify man-made contaminated waters. Throughout the course of the research, the methods of scanning electron microscopy, optical microscopy, dynamic light scattering, radiometry, and atomic absorption spectrophotometry were used. The use of the TEG–bentonite composite for the purification of the model water, simulating radioactively contaminated nuclear power plant (NPP) effluent, reduced the content of organic substances by 10–15 times, and the degree of extraction of cesium, strontium, cobalt, and manganese was between 81.4% and 98.8%. The use of the TEG–bentonite composite for the purification of real radioactively contaminated water obtained from the object “Shelter” (“Ukryttya” in Ukrainian), in the Chernobyl Exclusion Zone, Ukraine, with high activity, containing organic substances, including micro- and nanoplastics, reduced the radioactivity by three orders of magnitude. The use of cesium-selective sorbents for additional purification of the filtrate allowed for further decontamination of radioactively contaminated water with an efficiency of 99.99%. Full article

Polypropylene (PP) exhibits high flammability (LOI ≈ 17.5%), which limits its industrial applications. Previous studies have primarily focused on the flame-retardant mechanisms of intumescent flame-retardant (IFR) systems, while less attention has been given to the role of inorganic synergistic additives in balancing flame retardancy with mechanical performance—an aspect crucial for commercial applications This study investigated the effect of small additions of zinc oxide (ZnO) and manganese oxide (MnO) on the flame-retardant, mechanical, and thermal properties of PP/IFR (APP + PER) composites. The oxide content was varied between 0 and 2 wt.%. LOI and UL-94 tests showed that as little as 0.25 wt.% increased LOI to 30% and enabled all materials to achieve a UL-94 V-0 classification. The highest performance was observed for ZnO (LOI = 43.7% at 1.5 wt.%), while MnO induced a linear increase up to 38.6% at 2 wt.%. SEM analysis confirmed the formation of a compact, foamed char layer. Mechanical testing revealed improved stiffness (~15%) and flexural strength (~20%), with unchanged tensile strength but reduced impact strength (−50% for ZnO, −30% for MnO). The HDT increased from 55 °C to 65 °C. These findings demonstrate that small amounts of ZnO and MnO act as effective and economically viable IFR synergists in PP composites. Full article

Hericium erinaceus, a rare edible–medicinal fungus, has attracted great attention in food and pharmaceutical fields due to its rich nutritional and bioactive components. However, its traditional cultivation relies heavily on wood chip substrates, causing resource unsustainability. The “wood-replacing-with-grass” technology can address this issue, contributing to ecological conservation and alleviating resource conflicts between edible fungus cultivation and forestry development. This study focused on straw substitution for wood chips, initially screening suitable straw types and optimal addition ratios from 7 straw varieties, and systematically investigating the agronomic trait variations in H. erinaceus under different substrate formulations via cultivation experiments. Results showed the following: (1) Rapeseed straw, soybean straw, and corn straw substituting 20%, 30%, and 40% of wood chips, respectively, promoted better mycelial growth of H. erinaceus. (2) All screened straw formulations enabled fruiting. With increased straw addition, the mycelial full colonization time shortened (up to 5 days shorter in 40% corn/soybean straw treatments). The 20% corn straw treatment showed significantly higher biological efficiency and average fresh weight than the control (CK); the 20% soybean straw treatment had no significant difference in biological efficiency but significantly higher average fresh weight than CK; and the 20% rapeseed straw treatment showed no significant differences in both indexes from CK. However, when straw addition exceeded 20%, fruiting body firmness, yield, and biological efficiency decreased progressively. (3) The 40% soybean straw treatment yielded fruiting bodies with the highest crude protein, manganese, and iron contents, while the 40% rapeseed straw treatment had the highest crude fat, potassium, phosphorus, calcium, zinc, and selenium contents. These findings provide a theoretical basis and practical reference for optimizing H. erinaceus cultivation substrate formulations, improving product quality, and promoting sustainable industrial development. Full article

This research prepared and characterised novel mixed coordination complexes derived from escitalopram with eugenol and curcumin to form (L₁) and (L₂), respectively. The complexes were prepared via Williamson ether synthesis and analysed by FTIR, UV–Vis, ¹H-NMR spectroscopy, elemental analysis, molar conductivity, and magnetic susceptibility. The results confirmed their octahedral geometries. Magnetic investigation reported high-spin configurations for Mn(II), Co(II), and Ni(II) complexes, whereas Cu(II) exhibited a distorted octahedral arrangement with characteristic d–d transitions. In addition, the calculation of Density functional theory (DFT) provided more insight into the detailed structural and electronic properties of the new ligand and its complexes. Antimicrobial compounds were evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans through the agar well diffusion method. The reported results revealed that Cobalt complexes showed antimicrobial activity followed by Copper (Cu), Nickel (Ni) and Manganese(Mn) complexes, respectively, due to an increase in Co-lipophilicity, which leads to improved diffusion through microbial cell membranes. The research findings confirmed that escitalopram-based mixed ligands coordinate with transition metals and could have significant biological applications. Full article

Steel products play an important role in daily production and life as a common production material. Currently, the quality of steel products is judged by manual experience. However, various inspection criteria employed by human operators and complex factors and mechanisms in the steelmaking process may lead to inaccuracies. To address these issues, we propose a learning-based method for steel quality prediction, which is named DRBoost,based on multiple machine learning techniques, including Decision tree, Random forest, and the LSBoost algorithm. In our method, the decision tree clearly captures the nonlinear relationships between features and serves as a solid baseline for making preliminary predictions. Random forest enhances the model’s robustness and avoids overfitting by aggregating multiple decision trees. LSBoost uses gradient descent training to assign contribution coefficients to different kinds of raw materials to obtain more accurate predictions. Five key chemical elements, including carbon, silicon, manganese, phosphorus, and sulfur, which significantly influence the major performance characteristics of steel products, are selected. Steel quality prediction is conducted by predicting the contents of these chemical elements. Multiple models are constructed to predict the contents of five key chemical elements in steel products. These models are symmetrically complementary, meeting the requirements of different production scenarios and forming a more accurate and universal method for predicting the steel product’s quality. In addition, the prediction method provides a symmetric quality control system for steel product production. Experimental evaluations are conducted based on a dataset of 2012 samples from a steel plant in Liaoning Province, China. The input variables include various raw material usages, while the outputs are the content of five key chemical elements that influence the quality of steel products. The experimental results show that the models demonstrate their advantages in different performance metrics and are applicable to practical steelmaking scenarios. Full article

This study examines the pigments and materials used in Girolamo Romanino’s Musicians fresco (1537–1538), located in the Duomo Vecchio in Brescia, with the aim of identifying and analyzing the artist’s colour palette. Ten samples of the pictorial layer and mortar were collected from two frescoes and characterized using microscopic and spectroscopic techniques. Confocal laser scanning microscopy (CLSM) was used to define the best positions where single-point, spectroscopic techniques could be applied. Raman spectroscopy and micro-Fourier transform Infrared spectroscopy (micro-FTIR) were used to detect pigments and organic binders, respectively. X-ray powder diffraction (XRPD) provided additional insights into the mineral composition of the pigmenting layers, in combination with environmental scanning electron microscopy equipped with energy-dispersive spectroscopy (ESEM-EDS). The analysis revealed the use of traditional fresco pigments, including calcite, carbon black, ochres, and copper-based pigments. Smalt, manganese earths, and gold were also identified, reflecting Romanino’s approach to colour and material selection. Additionally, the detection of modern pigments such as titanium white and baryte points to restoration interventions, shedding light on the fresco’s conservation history. This research provides one of the most comprehensive analyses of pigments in Romanino’s works, contributing to a deeper understanding of his artistic practices and contemporary fresco techniques. Full article

The article deals with the analysis of the mechanical properties of the newly designed aluminum alloy Al-Si7CrMnCu2.5. The research was carried out in order to map a new alloy with a certain addition of chromium and manganese from the point of view of mechanical properties and their changes after heat treatment (hardening, artificial aging) with defined parameters. Specifically, properties such as strength limit, yield strength, ductility, hardness, and microhardness were analyzed, both in the cast state and after heat treatment. The alloy was designed as an alternative to the standard Al-Si alloys already used in practice (AlSi7Mg, AlSi7Mg0.3, AlSi8Cu2Mn, AlSi8Cu3), which are mainly used in the production of engine parts and other components for the automotive and aviation industries. As can be seen from the presented results, the experimental AlSi7CrMnCu2.5 alloy exceeds the properties of the other selected alloys by tens of percent already in the cast state in many parameters. After heat treatment, the results achieved are comparable to the mentioned alloys, and in most cases, their values exceed them, especially in terms of ductility and hardness. Full article

Background: Manganese (Mn) is a trace element essential for multiple physiological and biological processes. The testis plays a key role in male reproduction by producing sperm and synthesizing male hormones. This study investigates how Mn deficiency affects testicular development, spermatogenesis, and the blood–testis barrier (BTB), and evaluates associated variations in oxidative stress to explore potential mechanisms. Methods: A Mn-deficient diet was used to induce Mn deficiency in mice, with MnCl₂ administered via intraperitoneal injection. Mn levels in testicular tissue were measured by atomic absorption spectrometry. Testis and sperm morphology were assessed by H.E. and sperm staining. BTB markers were analyzed using immunofluorescence, Western blot, and qPCR. Oxidative stress was evaluated biochemically. Nrf2 pathway changes were detected by qPCR and Western blot. Results: The results indicated that Mn deficiency dramatically decreased the testicular index, caused abnormal testicular tissue structure, and significantly decreased Johnsen’s score. At the same time, sperm density and motility were significantly reduced, and the sperm deformity rate was significantly increased. In addition, the BTB function was impaired, as indicated by the significantly down-regulated expression of tight junction proteins including Occludin, ZO-1, JAM-A, and Claudin-11. As the oxidative stress levels increased, the mRNA and protein expression levels of molecules (including Nrf2 and HO-1) related to the Nrf2 signaling pathway were significantly down-regulated, while its inhibitor Keap1 exhibited significantly up-regulated expression. Notably, after supplementing MnCl₂, all the above abnormal indicators were significantly improved. Conclusions: Mn deficiency can lead to testicular tissue damage, decreased sperm quality, and BTB dysfunction, and the potential mechanism is probably closely associated with the increase in the oxidative stress level mediated by the Nrf2 pathway. Full article

Rechargeable aqueous Zn-MnO₂ batteries are positioned as a highly promising candidate for next-generation energy storage, owing to their compelling combination of economic viability, inherent safety, exceptional capacity (with a theoretical value of ≈308 mAh·g⁻¹), and eco-sustainability. However, this system still faces multiple critical challenges that hinder its practical application, primarily including the ambiguous energy storage reaction mechanism (e.g., unresolved debates on core issues such as ion transport pathways and phase transition kinetics), dendrite growth and side reactions (e.g., the hydrogen evolution reaction and corrosion reaction) on the metallic Zn anode, inadequate intrinsic electrical conductivity of MnO₂ cathodes (≈10⁻⁵ S·cm⁻¹), active material dissolution, and structural collapse. This review begins by systematically summarizing the prevailing theoretical models that describe the energy storage reactions in Zn-Mn batteries, categorizing them into the Zn²⁺ insertion/extraction model, the conversion reaction involving MnO_x dissolution–deposition, and the hybrid mechanism of H⁺/Zn²⁺ co-intercalation. Subsequently, we present a comprehensive discussion on Zn anode protection strategies, such as surface protective layer construction, 3D structure design, and electrolyte additive regulation. Furthermore, we focus on analyzing the performance optimization strategies for MnO₂ cathodes, covering key pathways including metal ion doping (e.g., introduction of heteroions such as Al³⁺ and Ni²⁺), defect engineering (oxygen vacancy/cation vacancy regulation), structural topology optimization (layered/tunnel-type structure design), and composite modification with high-conductivity substrates (e.g., carbon nanotubes and graphene). Therefore, this review aims to establish a theoretical foundation and offer practical guidance for advancing both fundamental research and practical engineering of Zn-manganese oxide secondary batteries. Full article

Aluminothermic reduction is gaining renewed interest as an alternative processing route for the circular economy. Aluminium is produced electrochemically in the Hall–Héroult process with minimal CO₂ emissions if electricity is sourced from non-fossil fuel energy sources. The Al₂O₃ product from the aluminothermic reduction process can be recycled via hydrometallurgy, with leaching as the first step. NaAlO₂ is a water-leachable compound that forms a pathway for recycling Al₂O₃ with hydrometallurgy. In this work, a suitable slag formulation is applied in the aluminothermic reduction of manganese ore to form a Na₂O-based slag of high Al₂O₃ solubility to effect good alloy–slag separation. The synergistic effect of added chromium metal as a collector metal is illustrated with an increased alloy yield at 68%, from 43% without added Cr. The addition of small amounts of carbon reductant to MnO₂-containing ore ensures rapid pre-reduction to MnO. This approach negates the need for a pre-roasting step. The alloy and slag chemical analyses are compared to the thermochemistry-predicted phase chemistry. The alloy consists of 57% Mn, 18% Cr, 18% Fe, 3.4% Si, 1.5% Al, and 2.2% C. The formulated slag exhibits high Al₂O₃ solubility, enabling effective alloy–slag separation, even at an Al₂O₃ content of 55%. Full article

Titanium–manganese alloys have emerged as a promising option of β-phase titanium alloys, which have recently gained popularity thanks to their exceptional cold strength, deformability, and high specific strength. In this study, the vacuum arc melting process was used to obtain a Ti3Mn alloy, and its behavior in three physiological conditions was analyzed: at room temperature, simulated fever conditions (at 40 °C), and simulated severe infection conditions (pH = 1.2). Optical and scanning electron microscopy were employed to study the effect of Mn addition on the Ti-base alloy microstructure. It was observed the formation of fine precipitates of Mn2Ti, localized at the grain boundaries, allow for the increase in microhardness and blocked their growth. The beta phase of titanium was obtained as fine lamellae with a low level of porosity. The microhardness values were higher than those reported for cp-Ti. The electrochemical tests have shown a high resistance to corrosion in the three analyzed conditions. On the sample’s surface, there is a passive bilayer film, composed of a porous one being in contact with the physiological liquid and a compact one in contact with the bulk alloy. The results obtained suggest that Ti3Mn alloy can be a promising low-cost biomaterial for biomedical applications. Full article

The aim of this study is to investigate the influence of Mo on the microstructure and mechanical properties of railway frog steel. To address the challenges of a coarse microstructure and alloy element segregation caused by the current casting method of railway frog steel, the application of thermal mechanical control process (TMCP) technology can achieve a uniform and refined microstructure and stable mechanical properties, which is progress for the development of high-manganese railway frog steel. The TMCP of four experimental steels with varying Mo contents of 0.02~1.01 wt.% was simulated using a Gleeble 3500. The mechanical properties were tested, and the microstructure of each sample was characterized. A single austenite formed in each Mo-containing steel. With the increased Mo content, the grain boundary carbides decreased due to the formation of carbides within the grains, and the austenite and twin sizes were refined. Moreover, grain boundary strengthening and dislocation strengthening increased, while solid solution strengthening and precipitation strengthening had little effect, leading to an increase in the final yield strength. The contribution of dislocation strengthening to the yield strength was 51~56%, indicating that dislocation strengthening was the most significant strengthening method in the high-manganese railway frog steel produced using the TMCP. The impact energy showed a trend of first increasing and then decreasing, and the impact energy reached the highest point when the Mo content was 0.30 wt.%. In addition, the mechanisms governing the effect of increased Si in controlling the final microstructure and mechanical properties are discussed. Full article

Deoxidation of liquid steel is a key link that affects the quality of environmentally friendly free-cutting steel. The selection and addition sequence of deoxidizer affects the composition, size, distribution, and morphology of non-metallic inclusions, which ultimately affect the machinability of free-cutting steel. The effects of deoxidation processes on inclusions in environmentally friendly free-cutting steel were studied by high-temperature experiments and thermodynamic calculations. The content of total oxygen and inclusion characteristics in steel were analyzed by an oxygen and nitrogen analyzer, a metallographic microscope, a scanning electron microscope, and an energy spectrum analyzer. The results show that the inclusions in the process of an initial Si-Fe alloy addition followed by a manganese addition (H1) are mainly Al₂O₃-SiO₂-MnO composite inclusions in the liquid phase. In addition to the liquid phase Al₂O₃-SiO₂-MnO complex inclusions in the MnO-rich region, there are also some solid phase Al₂O₃-MnO inclusions with high Al₂O₃ content in the process of an initial manganese addition followed by a Si-Fe alloy addition (H2). In the two deoxidation experiments, Bi particles mainly exist in the form of adhesion to MnS inclusions. Referring to H2, the average value and median of the aspect ratio is larger and the number of sulfide inclusions with aspect ratio greater than 1.0 increases significantly in H1. In addition, the spheroidization degree of MnS inclusions in the H2 is relatively good. Full article

In the present study, ultrasound-assisted extraction using deep eutectic solvents was proposed for the preparation of uniced and iced gingerbread cookies prior to the determination of four macronutrients (potassium, sodium, magnesium, calcium), four micronutrients (manganese, zinc, iron, copper), the presence of toxic metal (cadmium), and antioxidant capacity. With the addition of 30% water in each green solvent, three acidic deep eutectic solvents, comprising xylitol with malic acid, choline chloride with malic acid, and choline chloride with lactic acid, were tested for their efficiencies in the simultaneous extraction of elements and antioxidants. The synthesized deep eutectic solvents were characterized by infrared spectroscopy, which provided evidence of generating new hydrogen bonds between two components of these solvents. Element profiles were analyzed by inductively coupled plasma–mass spectrometry after the extraction using green solvents and the microwave-assisted acid digestion of gingerbread samples. It was found that two deep eutectic solvents containing malic acid exhibited high abilities for solubilization of macronutrients and manganese from the samples studied, while the best extraction efficiencies for Zn, Fe and Cu micronutrients were achieved when the lactic acid-based deep eutectic solvent was used. However, the antioxidant capacity, evaluated by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and cupric reducing antioxidant capacity (CUPRAC) methods, led to the selection of choline chloride–lactic acid as the most promising green solvent for extracting antioxidants from two types of gingerbread cookies. The deep eutectic solvent-based extraction conforms to the principles of green chemistry and is suitable for releasing elements and antioxidants from gingerbread cookies. Full article

This study investigated the combined effects of quinoa malt addition (0%, 5%, 10%) and grain variety (white, red, black) on the nutritional and sensory properties of quinoa sourdoughs. Quinoa malt supplementation significantly (p < 0.05) enhanced fermentation characteristics, increasing titratable acidity from 20.0–20.4 to 21.2–23.8 mL NaOH/10 g and dynamic viscosity up to 733 ± 5.59 mPa·s compared to 474–611 mPa·s in controls. Malt enrichment expanded the volatile profile from predominantly alcohols and acids to include 25 distinct compounds spanning esters, terpenes, aldehydes, phenols, and furans, creating more complex aromatic profiles. Lactic acid production increased significantly in all malted samples, reaching 12.92 ± 0.00 g/kg in black quinoa with 10% malt. Black quinoa sourdoughs exhibited superior nutritional density with the highest protein (17.3 ± 0.1%), total dietary fiber (17.94 ± 0.14%), potassium (7896 ± 176 mg/kg), and manganese (55.65 ± 0.47 mg/kg) contents (p < 0.05). White quinoa variants demonstrated the highest acidity (pH 4.28 ± 0.01) and mineral bioavailability (magnesium: 5371 ± 70 mg/kg), while red quinoa achieved maximum viscosity (733 ± 5.59 mPa·s) and zinc content (38.08 ± 0.26 mg/kg). Volatile compound distribution varied significantly by variety, with white quinoa favoring ester and terpene formation, red quinoa promoting aldehydes and terpenes, and black quinoa accumulating phenols and furans. These findings demonstrate that strategic combination of quinoa variety selection and malt optimization can produce functionally enhanced, gluten-free sourdoughs with targeted nutritional and sensory characteristics for specialty bakery applications. Full article