Search Results (73)

Uranium separation from aqueous media remains a critical challenge at the intersection of nuclear fuel cycle efficiency and environmental safety. Layered double hydroxides (LDHs) are promising adsorbents for U(VI) removal and serve as versatile inorganic matrices for the design of nanocomposite sorbents. However, the influence of their key structural parameter, Me²⁺/Me³⁺ cationic ratio, on sorption performance and composite functionality remains insufficiently explored. This study investigates how the Zn^2+/Al³⁺ ratio governs the structure, sorption kinetics, and U(VI) uptake mechanisms of Zn-Al LDH. Characterization by XRD, TEM, XPS, XAFS, cryogenic laser-induced fluorescence spectroscopy, Raman, and positron annihilation spectroscopy revealed that increasing Al³⁺ content up to the optimal ratio of 2/1 enhances sorption capacity through increased positive charge density, reaching maximum static (47.2 mg/g) and dynamic (17.05 mg/g) capacities. EXAFS and fluorescence spectroscopy demonstrate that U(VI) adsorption at pH 4.0 proceeds via inner-sphere complexation involving mononuclear uranyl carbonate/hydroxyl species (UO₂(CO₃)₂²⁻, UO₂(CO₃)₃⁴⁻, UO₂(OH)_n⁽²⁻ⁿ⁾) and polynuclear complexes, predominantly (UO₂)₂(CO₃)(OH)₃⁻. Further increase to Zn/Al = 1/1 induced mesopore narrowing and inhibited diffusion, drastically decreasing dynamic performance. These findings establish the Zn/Al ratio as a key parameter governing LDH sorption efficiency and provide a mechanistic basis for the rational design of LDH-based composite sorbents. Full article

The reconstruction of the Stuttgart Hauptbahnhof railway junction, known as Stuttgart 21, is a very large and long-term infrastructure project. The gradual extension of the project implementation creates a specific time period during which atypical vegetation management in the trackbeds takes place. The vegetation of the trackbeds of the current station includes a total of 68 plant taxa, with Erigeron bonariensis L., Geum urbanum L. and Senecio inaequidens DC being significantly represented, for example. The limited level of disturbance within this “time window” creates favorable conditions in particular for the development of woody plants and lianas, such as Acer campestre L., Acer pseudoplatanus L., Ailanthus altissima (Mill.) Swingle, Clematis vitalba L., Ficus carica L., Hedera helix L. and Sambucus nigra L. The detected spectrum of plant taxa also indicates the formation of a diverse mosaic of microhabitats, which allows the coexistence of species with different ecological requirements. The assessed railway lines also provide space for the occurrence of non-native species, many of which are capable of effective wind dispersal and can subsequently colonize surrounding urban areas. Habitats with a time window of limited vegetation management may represent a poorly described factor influencing the spread of some taxa in the technosphere. The knowledge gained may contribute to a better understanding of the population dynamics of individual taxa and their potential for further spread. Full article

Lithium-ion batteries require cathode materials with high capacity and cycling stability. Li₃V₂(PO₄)₃ (LVP) offers a theoretical capacity of 197 mAh/g but suffers from poor electronic conductivity. In this study, a Li₃V₂(PO₄)₃/carbon (LVP/C) composite was synthesized via a citric acid-assisted sol–gel method. The effects of pyrolysis temperature (700–1000 °C) and citric acid-to-salt ratio (1:1, 0.5:1, 0.25:1) were systematically investigated. The optimal composite was obtained at 900 °C with a 1:1 ratio. This material exhibited a well-crystallized monoclinic structure (space group P2₁/c) with unit cell volume of 890.61 ų. The amorphous carbon coating provided a specific surface area of 33.03 m²/g. Electrochemically, the optimal LVP/C_1:1 composite delivered an initial specific capacity of 114 mAh/g at C/10 rate—twice that of samples with lower carbon content. It also demonstrated 100% capacity retention after 25 cycles with favorable coulombic efficiency (67%) and reduced charge-transfer resistance. These results show that pyrolysis at 900 °C with a 1:1 citric acid-to-salt ratio provides an optimal balance between crystallinity, carbon coating uniformity, and electrochemical performance for high-performance LVP/C composite cathodes. Full article

Technology is increasingly central to sustainability, yet frameworks built around the environmental–social–economic (E–S–Ec) triad and ESG disclosure regimes do not fully capture the governance problems created by interconnected digital and cyber–physical infrastructures. In this conceptual paper, Tech4.0 is used in a deliberately narrow working sense, focusing on AI-mediated decision systems, data/platform/cloud infrastructures, software dependency chains, and cyber–physical control environments in which opacity, infrastructural dependence, interdependence, and cascading failures create distinctive problems of governability and resilience. Against this background, the paper examines whether making the technological dimension explicit adds analytical value within sustainability architecture. It examines the case for treating Technological Sustainability (T) as a distinct analytical dimension/pillar insofar as it foregrounds system properties of the Technosphere that tend to be diluted when distributed across environmental, social, and economic categories. The paper then discusses the hierarchy T → Corporate Technological Responsibility (CTR) → Corporate Digital Responsibility (CDR) as a possible corporate-level operational pathway and outlines an exploratory measurement agenda structured around exposures, capabilities, and outcomes. Rather than offering empirical proof or a validated reporting architecture, the article provides a conceptual research program for later empirical inquiry into technological accountability under Tech4.0 conditions. Full article

Founded in 1703, St. Petersburg was the capital of the Russian Empire. Its historic center and associated monuments are inscribed as a UNESCO World Heritage Site. Its components are classified as cultural rather than natural or mixed. We hypothesized that a part of them has an additional ecotourism value. We carried out field observations along with a review of the literature. Our results confirmed the hypothesis: many of these sites retain important elements of biodiversity that can be used for environmental education. Large congregations of birds can be observed in close proximity to Heritage monuments. Wintering bats occupy the interiors of historic fortifications, and in summer, concentrations of feeding bats can be found nearby. Seal haul-out sites have been documented on small islands near the city. The ecotourism and nature-conservation value of these Heritage landscapes is usually linked to the original logic of their selection. The best locations were chosen for palace construction—dry, scenic areas with fertile soils suitable for park creation. Proximity to bodies of water was equally important, both for aesthetic reasons and for sanitation. These same qualities also make such areas highly favorable for biodiversity. Even after centuries of development, many natural features have persisted. Full article

Between 1959 and 1962, Alvin Scodel, J. Sayer Minas, and colleagues conducted some of the earliest laboratory studies of strategic interaction using non-zero-sum games. Working at the margins of economics in the Journal of Conflict Resolution, they documented a striking pattern: subjects frequently chose options that reduced an opponent’s payoff by more than their own, even when mutual cooperation was both individually and collectively optimal. These results—especially the behavior observed in their so-called Game H4, a Harmony Game in which cooperation strictly dominated defection—anticipate a central insight of evolutionary game theory: what matters for adaptation is relative payoff, not absolute gain. This essay reinterprets the Scodel–Minas experiments through a Darwinian lens, arguing that they provide an early empirical challenge to Nash-equilibrium reasoning and to models that evaluate strategies solely in terms of absolute utility. By reconstructing the H4 payoff structure and embedding it within a simple evolutionary framework, I show how small levels of “competitive” behavior can destabilize cooperative equilibria that appear self-evident under standard assumptions. I then revisit three later “puzzles” in the evolution of cooperation—altruistic punishment, the fragility of “win–win” treaties, and rejections in ultimatum bargaining—to ask how differently they might have been framed had the Scodel–Minas findings been part of the canonical experimental literature. Rather than treating these phenomena as surprising anomalies, a historically informed, relative-payoff perspective suggests that they could have been recognized much earlier as natural expressions of an already documented pattern. Full article

Developing polymer composites with improved mechanical and thermal properties requires strategies to overcome the problem of agglomeration and weak interfacial interactions of carbon nanofillers. This paper presents an effective strategy for the covalent functionalization of graphene oxide (GO) with melamine to create high-performance epoxy nanocomposites. The functionalization results in the formation of nitrogen-containing heterocyclic structures on the GO surface, as confirmed by FTIR and Raman spectroscopy. The addition of the obtained modified filler (mel-GO) into the epoxy matrix provides a synergistic effect: the melamine amino groups catalytically accelerate curing, reducing the gelation time from 146 to 48 min and increasing the maximum self-heating temperature from 94 to 122 °C, thus indicating enhanced interfacial interaction. This interaction results in a remarkable overall improvement in mechanical properties: tensile and flexural strengths increase by more than 20%, and elastic moduli by 31% and 58%, respectively, compared to the composite containing unmodified GO. At the same time, impact strength (from 14 to 23 kJ/m²) and hardness (up to 87 Shore D) increase. A key achievement is a dramatic increase in thermal and thermal-oxidative stability: the onset temperature of decomposition (T₅%) increases by 27 °C, the half-decomposition temperature (T₅₀%) by 45 °C, and the thermal stability index (THRI) increases from 119.3 to 128.9 °C. A more than twofold increase in coke residue yield (to 9.29%) and an increase in the Vicat softening point to 175 °C confirm the formation of an effective thermally stabilizing barrier layer due to the combined action of nitrogen-containing groups and dispersed graphene flakes. The proposed approach to functionalizing graphene oxide with melamine opens the way for the creation of next-generation epoxy composites with a record-breaking combination of strength, impact toughness, and thermal stability for applications in aerospace, electronics, and composite structures operating under extreme conditions. Full article

Phosphate coatings were obtained by cold method from solutions based on Mazev Salt (containing Mn(H₂PO₄)₂∙2H₂O and iron phosphates). Metal nitrates and nitrites were introduced into solutions as accelerators of the phosphating process. To obtain green and blue phosphate coatings, procyon olive green and methylene blue dyes (8 g/L) were added into the solutions. Colored phosphate coatings are deposited unevenly on the steel surface. The thickness of the modified phosphate films was estimated from SEM images of the cross-section samples and determined to be 3–4 microns. Colored phosphate coatings are fine-grained with a grain size of 170–190 nm, which was determined using an atomic force microscope. Phosphate films continue to exhibit protective properties when heated to 100 °C. With a further increase in temperature, the protective ability of the film is significantly reduced. Colored phosphate films have a low coefficient of friction (0.1–0.15). The breakdown voltage of colored phosphate coatings is 180–200 V, which characterizes low electrical insulation ability. Based on the established properties, colored phosphate coatings can be used as protective and decorative. Full article

The article presents a comprehensive comparative performance evaluation and validation of composite adsorbents based on the Se-derivative of 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide for U (VI) recovery from complex multicomponent aqueous media. Our results indicate the composite materials to be comparable to, and in some cases to surpass, existing adsorbents in recovery efficiency. Under static sorption conditions for trace U (VI) from real multicomponent solutions (tap, river, and sea water), the sorption efficiency reached 80–98%, while the distribution coefficients ranged from 10⁴ to 10⁶ cm³ g⁻¹. The sorption-selectivity properties of the materials were evaluated in the presence of competing ions (EDTA and oxalate ions), which possess a high chelating capacity and a strong tendency to form complexes with uranium. The dependence of sorption efficiency on the concentration of these ions and the solution pH was investigated. The possibility of reusing the materials over multiple sorption-desorption cycles was assessed. An optimal regenerating eluent agent was identified (NaHCO₃/NH₄NO₃), providing a desorption efficiency of >95% without degrading the material’s sorption properties over repeated cycles. Using a combination of physicochemical methods, including sorption techniques, the mechanism of uranium sorption and its dependence on the material structure were determined. The efficiency of uranium recovery from multicomponent natural waters was also investigated under dynamic conditions over repeated sorption-desorption cycles. The results demonstrate through comparative analysis that the developed composites exhibit a high sorption capacity and possess a high practical potential for the concentration and recovery of uranium from high-salinity solutions with complex composition. Full article

This study describes the results of integrative analysis of cyanobacterial communities in waterbodies of Moscow, Russia. 16S rRNA V3–V4 metabarcoding and light microscopy are implemented to investigate the diversity, abundance, and distribution of cyanobacteria, including the representatives of potentially toxigenic taxa—Anabaena, Aphanizomenon, Dolichospermum, Microcystis, and Planktothrix. High convergence is observed between microscopy and metabarcoding data for dominant genera, including Microcystis and Planktothrix. Sequence verification reveals total (100%) similarity between previously isolated toxigenic strains (e.g., Microcystis aeruginosa CBMC403m and CBMC523m) and corresponding highly abundant ASVs. In addition, current study ascertains the efficiency of metabarcoding for detection of rare cyanobacterial taxa missed by microscopy. We hereby acknowledge the limitations of V3–V4 16S rRNA-based metabarcoding approach for region species-level resolution and distinguishing potentially toxigenic taxa of cyanobacteria. At the same time, our findings validate metabarcoding as a rapid and reliable tool for monitoring of CyanoHABs in urban water ecosystems. Full article

The depletion of global lithium reserves, coupled with the necessity for environmentally sustainable and economically accessible energy storage systems, has driven the development of sodium-ion batteries (SIBs) as a promising alternative to lithium-ion technologies. Among various anode materials for SIBs, hard carbon exhibits obvious advantages and significant commercial potential owing to its high energy density, low operating potential, and stable capacity retention during prolonged cycling. Biomass represents the most attractive source of non-graphitizable carbon from a practical standpoint, being readily available, renewable, and low-cost. However, the complex internal structure of biomass precursors creates significant challenges for precise control of microstructure and properties of the resulting hard carbon materials, requiring further research and optimization of synthesis methodologies. This work reports the synthesis of hard carbon from Sasa kurilensis via pyrolysis at 900 °C and investigates the effect of alkaline pretreatment on the structural and electrochemical characteristics of the anode material for SIBs. Sasa kurilensis is employed for the first time as a source for non-graphitizable carbon synthesis, whose unique natural vascular structure forms optimal hierarchical porosity for sodium-ion intercalation upon thermal treatment. The materials were characterized by X-ray diffraction, infrared and Raman spectroscopy, scanning electron microscopy, X-ray microtomography and low-temperature nitrogen adsorption–desorption. Electrochemical properties were evaluated by galvanostatic cycling in the potential range of 0.02–2 V at a current density of 25 mAhg⁻¹ in half-cells with sodium metal counter electrodes. The unmodified sample demonstrated a discharge capacity of 160 mAhg⁻¹ by the 6th cycle, with an initial capacity of 77 mAhg⁻¹. The alkaline-treated material exhibited lower discharge capacity (114 mAhg⁻¹) and initial Coulombic efficiency (40%) due to increased specific surface area, leading to excessive electrolyte decomposition. Full article

Chrysastrella is a small genus of the Ochromonas-like chrysophytes, taxonomy and phylogenetic placement of which remained unclear. For a long time Chrysastrella was considered a cyst genus, i.e., a morphogenus based on the structure of stomatocysts, the resting stages of chrysophytes. We isolated several new strains of C. paradoxa from the peat bogs in Murmansk Region and the Republic of Komi (Russia) and studied them using light and scanning electron microscopy as well as molecular techniques. We showed that morphological differences between C. paradoxa, C. minor and C. breviappendiculata are within the range of variability of stomatocysts during development. So, we synonymized C. minor and C. breviappendiculata with C. paradoxa. Molecular phylogenetic analysis based on SSU rDNA and rbcL sequences revealed that Chrysastrella belongs to the order Chrysosaccales. A new monotypic family, Chrysastrellaceae fam. nov., was formally described to accommodate this genus. Full article

The article examines the synthesis and electrophysical properties of spinel ferrite ZnFe₂O₄, produced using the sol–gel method with a solid-state finishing process; as well as through classical ceramic technology with mechanochemical activation. The study includes a detailed analysis of the phase composition and crystalline structure using X-ray diffraction; infrared spectroscopy; mass spectrometry; and thermogravimetric and differential thermal analyses. These methods help identify thermal effects and the stages of synthesis. Impedance spectroscopy is used to investigate the electrophysical properties, revealing a significant influence of firing temperature on electrical ionic conductivity. The results show that the electrophysical properties differ based on the synthesis conditions and methods. This suggests potential applications for ZnFe₂O₄ as a cathode material in metal-ion batteries. The work highlights the importance of optimizing synthesis conditions to achieve high-performance characteristics in electrode materials. Full article

This article reveals the nature, causes, and main stages of occurrence and development of endogenous fires in coal mines. It is emphasized that one of the key tasks of fire protection specialists is the most accurate determination of the stage of oxidation and self-heating of coal. A review of existing gas analysis methods for identifying the initial and subsequent stages of endogenous fire development is conducted. Particular attention is focused on the importance of obtaining prompt reliable information on the self-heating temperature of coal and the dynamics of its change in the early stages of the process. Since self-heating zones are usually inaccessible for direct instrumental control, the main source of information is the gas analysis of air samples. The authors present the results of research on the dependence of the indicator gas content on the coal self-heating temperature. Based on the Graham criterion, the stages of thermal development of the process are predicted. Correlation dependencies between temperature and integral parameters of indicator gas concentrations are developed, allowing for a sufficient degree of reliability in determining the stages of coal self-heating and spontaneous combustion. Based on the results of the work, methodological recommendations for the prevention and warning of endogenous fires in coal mines and opencasts are proposed. They are based on the most informative and accessible signs suitable for quantitative assessment. The implementation of these recommendations will improve the level of industrial safety and reduce the risks of fires and explosions during mining operations. Full article

Understanding and predicting the damage to concrete caused by microorganisms in aquatic environments is challenging, highlighting the need for effective, simple, and inexpensive preventative methods. This paper presents the results of a study on the effect of calcium stearate addition on the kinetics of mass transfer processes occurring in cement stone exposed to Aspergillus niger fungi under humid conditions. Calcium stearate was added into the cement mix during sample preparation at concentrations of 0.5% and 1% by cement weight. After curing, the cement stone surfaces were inoculated with Aspergillus niger. To investigate mass transfer processes during biodegradation, the samples were immersed in water. Calcium leaching from the cement stone was quantified using complexometric titration of the water, while the calcium content within the cement stone was determined by derivatographic analysis. The quantitative indicators of calcium leaching in water from cement stone with calcium stearate additives were 2.5 times lower. The profiles of calcium concentrations in the thickness of cement samples demonstrated an increase in the intensity of mass transfer under the influence of fungi and a significant decrease in the processes in hydrophobic cement stone. The values of the mass conductivity coefficients for fungal-infected samples in water differed by two orders of magnitude from 10⁻⁹ and 10⁻¹¹ [m²/s] for conventional and hydrophobic concrete. The mass transfer parameters (flow density, mass conductivity coefficients, and mass transfer coefficients) revealed a 3-fold slowdown in mass transfer processes during fungal exposure in cement stone with a hydrophobic additive compared with control samples. A mathematical model of concrete biocorrosion was used to predict the durability of concrete under humid conditions with fungal exposure. The predicted maintenance-free service life of concrete without additives is 15 years, whereas for hydrophobic concrete, it is 25 to 30 years. The research results are used in the design of concrete structures in conditions of high humidity, in the development of new compositions of hydrophobic concretes, to predict the service life of concrete structures, and in the creation of methods for preventing biological damage to concrete structures. Full article