Search Results (102)

This paper presents a comparative analysis of selected economic indicators within the Italian railway passenger transport sector during the 2010–2024 period. Characterized by high-speed rail (HSR) saturation and advanced market liberalization, the Italian railway system serves as a reference model for investigating structural shifts within mature transport networks. The study aims to quantify the dynamics of transport performance through a synthesis of multiple analytical dimensions: passenger volume, transport performance (passenger-kilometers), modal split, average transport distances, and indicators of general and dynamic population mobility. The methodological framework is based on the application of chain and base indices, enabling the precise identification of cyclical fluctuations, exogenous disruptions (primarily the impact of the COVID-19 pandemic), and the subsequent degree of systemic resilience. The analysis suggests a significant shift in demand composition after 2014, characterized by an expansion of short- and medium-distance segments alongside a transformation in travel behavior. The research findings determine the correlation between infrastructure investment and the actual positioning of rail transport within a multimodal system. This work provides an analytical foundation for strategic planning in transport policy and sustainable mobility within the context of European transport integration. Moreover, these insights are practically applicable for transport operators and planners in forecasting demand, optimizing network capacity, and enhancing infrastructure resilience against future exogenous shocks. Full article

This study explores the degree of capital mobility in selected APEC economies over the period 2000–2023, using a consumption-based approach. The motivation stems from the well-known limitations of the traditional investment–saving framework associated with the Feldstein–Horioka puzzle, which may not fully capture how capital actually moves across borders. To address this issue, the paper adopts an alternative perspective by examining how domestic consumption responds to external consumption patterns relative to domestic income. The analysis focuses on six economies, including both developed countries (the United States, Canada, and Australia) and developing countries (Chile, Thailand, and Indonesia), allowing for a meaningful comparison across different levels of economic development. The findings indicate that capital is indeed mobile, but not perfectly so. More notably, the results suggest that capital mobility tends to be stronger in developing economies than in developed ones. This outcome challenges conventional expectations based on standard measures of financial openness and highlights the gap between formal financial liberalization and actual capital movement in practice. Overall, the study provides a deeper understanding of capital mobility and offers useful insights for policymakers seeking to enhance financial integration and improve the effectiveness of capital flow management, particularly in developing economies. Full article

Since 1978, Chinese–foreign cooperation in running schools (CFCRS) has evolved from fragmented pilot initiatives into a policy-coordinated system of higher education internationalization. This study employs an exploratory sequential mixed-methods design to examine how national policy shifts reshaped the structure of CFCRS collaboration networks between 1978 and 2025. Integrating longitudinal policy analysis with Social Network Analysis (SNA), the research identifies five policy-driven stages: exploratory opening, legal institutionalization, regulated development, quality enhancement, and strategic repositioning. Network analysis shows that increasing density, expanding degree centrality of leading institutions, and greater diversification of international partners reflect growing integration into global transnational higher education networks. At the same time, persistent structural concentration in key institutional hubs and regulated entry into partnerships indicate strong path dependence shaped by state-steered governance. The network also exhibits a disciplinary shift toward engineering and STEM collaborations aligned with national innovation strategies, alongside gradual spatial diffusion from coastal regions toward central and western provinces. Conceptually, the findings demonstrate that state-coordinated internationalization can generate dense and diversified collaboration networks without fully liberalizing governance structures. The CFCRS case thus illustrates a model of hybrid governance, where centralized policy coordination coexists with expanding network-based international partnerships. Full article

The sustainable role of higher education and its governance logic is increasingly prominent in national artificial intelligence (AI) strategies. Based on core AI-related policy documents issued by China, Japan, and South Korea between 2017 and 2025, the corpus-based analysis conducts a systematic comparison, by means of text coding, from strategic positioning, policy architecture, educational philosophy, and a governance model. All three countries have established AI as a critically sustainable component of national development strategy and explicitly defined its functional role in higher education at the strategic level. However, varied distinct differences are found in the policy implementation approaches and governance structures. China adopts a centralized, state-led approach characterized by a high degree of integration among institutional instruments. Japan reinforces liberal education reform in the context of higher education and extends educational responsibilities across society through a lifelong learning framework. Driven by global technological competition, South Korea advances digital transformation of the education system, while building a trustworthy AI governance system. These divergent policy models reveal the sustainable interplay between national AI strategies and higher education. Overall, our findings indicate that the evolution trajectories of AI strategies affect the stability and adaptive capacity of higher education systems in the long term. Full article

This study investigates the comminution behavior and beneficiation potential of lithium-bearing ores, zinnwaldite from Cínovec (Czech-Germany border) and lepidolite from Villasrubias (Spain) by integrating mineralogical analysis and mechanical characterization. The research is driven by Europe’s need for secure lithium supply chains. In particular, it focuses on the challenges associated with low-grade, fine-grained lithium micas found in hard-rock ores, which offer significant potential to supply in Europe but also pose substantial processing challenges. QMA (Quantitative Microstructural Analysis) revealed distinct differences in the textural and structural characteristics of the studied ores. Zinnwaldite-bearing rocks are coarser-grained with high interlocking and roughness, while lepidolite-bearing samples showed finer grains, lower roughness, and more disseminated mica distribution, indicated by their low clustering degree. In terms of mechanical characterization, zinnwaldite-rich ores have the lowest compressive strength, while lepidolite-rich samples showed the highest values, attributed to their finer grain size and more cohesive structure. This suggests that lepidolite may require higher energy input and finer crushing stages to achieve the target liberation size. These features influenced the breakage behavior observed during mechanical testing and comminution and are essential for enabling selective comminution, separating mica from gangue material. This study contributes to analyzing the potential of European hard-rock lithium resources from the perspective of upstream comminution, which is an essential step influencing downstream energy consumption, reagent use, and overall recovery efficiency. The results of this research emphasize that selective comminution should not rely solely on mineral hardness contrasts but must incorporate microstructural parameters such as clustering, grain size distribution, and orientation. Full article

This study examines the determinants of tourism resilience and recovery following global crises using a comparative cross-country approach. A composite Tourism Resilience Index (TRI) is constructed based on post-crisis recovery in tourism employment, tourism GDP and international arrivals, and its determinants are analyzed through descriptive, correlational and exploratory multivariate regression analysis. The results reveal significant heterogeneity in resilience trajectories across countries, indicating that income level alone does not explain recovery patterns. Institutional and structural factors, including the degree of economic liberalization and market composition, play a critical role in shaping post-crisis tourism performance. These findings contribute to the literature on tourism resilience by providing empirical evidence with policy implications for improving adaptive capacity in tourism-dependent economies. Furthermore, the results highlight the multidimensional nature of tourism resilience and provide evidence-based insights for the design of differentiated policy strategies aimed at strengthening the sector’s capacity to withstand future global crises. Full article

Coal preparation tailings from the K18 seam of the Abayskaya mine were evaluated as a potential secondary source of critical rare earth elements (REEs). The study showed that REEs are predominantly associated with the mineral fraction of coal; therefore, during beneficiation, approximately 70% of their total content is transferred to flotation tailings. The concentrations of valuable elements in the tailings are as follows (g/t): Li—65; Sc—16; Y—17; Yb—2.5; V—135; and Ti—2293. These values significantly exceed the Clarke values and are comparable to those of some low-grade primary ores, indicating the potential of coal preparation wastes as a technogenic raw material for critical elements. To extract REEs from the resistant aluminosilicate matrix, a fluorine–ammonium sulfate thermochemical activation method was proposed. Using a probabilistic–deterministic experimental design approach, a mathematical model of the process was developed and optimal parameters were determined (400 °C, 120 min, (NH₄)₂SO₄ consumption—140% relative to Al, NH₄HF₂ consumption—110% relative to Si), providing a feed liberation degree (by Al extraction) of up to 94%. Under optimal conditions, high leaching efficiencies of key elements were achieved: Sc (95%), Y (100%), Yb (100%), and Li (100%). The results demonstrate the significant potential of coal preparation tailings as a secondary resource of rare earth elements and confirm the efficiency of fluorine–ammonium sulfate technology for processing this type of technogenic waste. Full article

This study systematically investigates the reaction characteristics of laminated shale oil reservoirs in the 7₃ sub-member of the Yanchang Formation, Heshui area, Ordos Basin, under exposure to CNI-I nanoviscous fracturing fluid. The reservoir matrix comprises 84.85% brittle minerals and 15.15% clay minerals. Fluid–rock interactions significantly dissolve calcite and dolomite, releasing Ca²⁺ and Mg²⁺ ions, while clay mineral reactions liberate substantial amounts of Na⁺. Post-reaction, fluid system stability is markedly reduced, elevating the risk of precipitate formation and pore-throat plugging. Exposure to fracturing fluid reduces the T₂ cutoff value of core samples from 3.29 ms to 1.72 ms, indicating a densification of the micro-pore-throat network and a decline in mobile fluid saturation, while fracture apertures exhibit widening. Based on empirical data, a discriminant criterion (R value) defined as the ratio of fracture aperture increment rate to pore-throat diameter reduction rate is established at 1.25, confirming that fracture propagation dominates over pore constriction. Dual-medium modeling yields a net permeability enhancement of 19.35%. Fluid–rock interactions induce overall degradation of rock mechanical properties with pronounced anisotropy: rock strength along the direction perpendicular to bedding declines by 37.546%, Young’s modulus decreases by 1.81%, and Poisson’s ratio increases by 0.02%—all significantly exceeding the degree of degradation parallel to bedding. This anisotropic mechanical degradation predisposes the near-wellbore region to shear slip and wall spalling, prompting the development of targeted engineering mitigation strategies. Full article

China’s coking coal resources are scarce, and maximizing the recycling of these resources is the primary objective of coal processing and utilization. The embedding features of inorganic minerals within coking middling coal resources are an inherent factor influencing their liberation and separation efficiency. However, current research lacks a systematic investigation into how the embedding features of inorganic minerals in coking middling coal affect their liberation characteristics and flotation separation performance. This study examines three Chinese coking middling coal samples with distinct embedding features. Based on quantitative characterization of inorganic mineral embedding, grinding tests with varying durations and flotation separation tests on post-grinding products were conducted. Liberation and separation efficiencies were evaluated to explore the influence of inorganic mineral embedding on liberation degree and the subsequent impact of the liberation degree on flotation performance. The results indicate that the three coking middling coal samples with different embedding features exhibit significant differences in the dissociation behavior between inorganic minerals and organic matter. The particle size (D) of inorganic mineral phases is the primary factor influencing the liberation degree of inorganic minerals, while the complexity of intergrowth between inorganic minerals and organic matter (CIG) is a secondary factor. The CIG is the primary factor affecting the liberation of organic matter. As the liberation of inorganic minerals and organic matter increases, the separation efficiency improves for the Liuwan middling coal samples, whereas it deteriorates for the Shaqu and Changzhi samples. Full article

Mineral processing may decisively influence recycled aggregate (RA) production, yet it is systematically underreported. This critical review screened 338 Scopus-indexed publications (2004–2024) and retained 204 studies after eligibility assessment. Reporting on comminution was limited: ~52% (105 studies) of studies did not explicitly mention crushing, while ~26% (53 studies) identified the crusher type, and only about 1% (two articles) reported operating conditions, which undermines reproducibility and cross-study comparability. RA quality is application-/market-dependent. The literature was classified into cement-based materials (46.1%), pavement applications (44.6%), and fundamental studies without application (9.3%). For cement-based materials, water absorption and compressive strength were the most frequently reported primary and secondary properties, respectively. For pavement applications, particle-size distribution and optimum moisture content predominated. Overall, mineral processing directly governs the primary attributes of recycled aggregates (RAs) and indirectly influences their secondary performance outcomes. The main gap identified in the literature is the lack of clear recommendations for processing procedures, which limits the reproducibility and comparability of reported results. To address this limitation, this article proposes a mineral-processing framework intended to standardize both RA processing and reporting practices, thereby improving crosslink study comparability, experimental reproducibility, and evidence-based specification according to end-use requirements. Full article

Constrained by the low grade and poor floatability of the run-of-mine ore, the beneficiation of porphyry-type copper–molybdenum sulfide ores generates large quantities of molybdenum tailings, leading to significant environmental risks and resource losses and necessitating urgent recovery and reutilization. In this study, a representative sample of molybdenum tailings with a Mo grade of 0.354% was investigated to analyze its process mineralogy. The results show that molybdenite predominantly exists as fine, flaky particles intimately intergrown with quartz, pyrite, and aluminosilicate minerals, exhibiting an extremely low degree of liberation and an overall ultrafine particle size. Laboratory flotation tests show that the flotation kinetics conform to a first-order model; however, a considerable amount of molybdenum remains in the tailings, indicating that the mineralization process needs to be intensified. Through structural optimization and confined-space design, a vortex-based mineralization reactor was developed. Computational fluid dynamics simulations demonstrate that the mineralizer can generate flow fields with high turbulence intensity and dissipation rates and can induce high-energy, small-scale micro-vortices. On this basis, a semi-industrial rougher flotation system was established by coupling the developed mineralizer with a flotation column. Under optimized operating conditions, namely a feed pressure of 0.06 MPa and an impeller frequency of 20 Hz, single-stage treatment of the tailings produced molybdenum concentrates with a grade of 1.90% and a recovery of 81.29%, while the Mo grade of the tailings was reduced to 0.08%. The results are markedly superior to those obtained using a conventional laboratory flotation cell, demonstrating a substantial enhancement in mineralization efficiency and molybdenum recovery. The proposed approach, therefore, provides a practical reference for the flotation recovery of molybdenum tailings as well as other micro-fine, low-grade metal tailings. Full article

Spirulina (Arthrospira platensis) is recognized as a high-protein microalga with potential for bioactive peptide production. In this study, S. platensis protein extract (~45% protein) was subjected to enzymatic hydrolysis using pepsin, trypsin, and chymotrypsin. A ~75% reduction in Bradford values indicated extensive protein breakdown, with degrees of hydrolysis of 15.6%, 21.4%, and 33.7% for pepsin-, trypsin-, and chymotrypsin-treated samples, respectively. SDS-PAGE confirmed the generation of low-molecular-weight peptides (<10 kDa). Hydrolysis caused only minor changes in amino acid composition, maintaining protein quality, with trypsin-hydrolysates showing the highest protein efficiency ratio (1.12) and biological value (78.83%). Antioxidant capacity increased significantly, with hydrolysates displaying a 33–68% rise in DPPH and 30–54% in FRAP activity, alongside a 33–44% reduction in lipid peroxidation. Furthermore, phytochemical content was markedly enhanced in hydrolysates compared to intact protein, with increases in total phenolic content (38–118%), total flavonoid content (59–78%), and terpenoids (24–37%). Among treatments, trypsin-SPPH (Spirulina platensis protein hydrolysate) consistently exhibited the most pronounced improvements. Collectively, these findings demonstrate that proteolysis of S. platensis proteins not only enhances antioxidant activity but also liberates bound phytochemicals, establishing S. platensis hydrolysates as promising functional food and nutraceutical ingredients. Full article

This study provides a comprehensive characterization of the low-to-intermediate sulfidation (LS-to-IS) epithermal Molai Zn-Pb±(Ag,Ge) ore (Vigla-Mesovouni orebody) in Laconia, Greece, and provides insights on how such data may be employed in beneficiation flow-sheet design. Detailed mineralogical, chemical, textural, and physicochemical characterization defines a systematic transition from early refractory Ge-rich to late-stage refractory Ag-rich mineralization, including sulfides and fahlores. Germanium, although present in all sphalerite varieties (Sp-I, Sp-II, and Sp-III), is predominantly enriched in early sphalerite (Sp-I, up to 1891.60 ppm). Interestingly, Ge is also enriched in early Py-I pyrite, with content reaching up to 383 ppm. Silver is mainly concentrated in late-stage tetrahedrite Ttr-II (up to 3.60%), galena (Ga-II), and, to a lesser extent, late sphalerite (Sp-III). Liberation studies reveal effective liberation of Py-I and Sp-I, major Ge carriers, in the coarser fractions (+0.150 mm) and near complete liberation of all ore phases below 0.036 mm. Combined beneficiation via Wilfley pre-concentration and differential flotation produced up to ~35% Pb and ~65% Zn at >85% recovery for the smallest fractions (−0.036 mm). Ore characterization revealed that secondary circuits may be developed to further enhance the economic value of Molai ore (Ge from Py-I, and Ag±[Sb,As] from Ttr-II and Ag-bearing sulfosalts), which are dismissed as wastes in Pb and Zn flotation circuits. The results of our study establish a robust foundation for the design of tailored, multi-stage metallurgical flow-sheets aimed at maximizing the economic value of the Molai epithermal resource. Full article

The increasing complexity of energy systems amid the global push for decarbonization raises important questions about how transitions in the energy matrix affect financial risk in electricity markets. This study investigates the relationship between structural changes in national energy matrices and the systemic risk associated with electricity prices in Europe from 2015 to 2022. Using daily electricity price data, we calculate log returns and estimate the Value at Risk (VaR) at the 1% level as a measure of extreme financial loss. We incorporate energy market variables, including the volatility of Brent oil and coal prices, and an entropy-based indicator derived from the Shannon index, which captures the degree of technological dispersion in the energy mix over time. A fixed-effects panel regression model is applied across 21 European countries to identify the drivers of energy-related financial risk. Results show that higher volatility in Brent and coal prices significantly increases the VaR, and that greater entropy reflecting a more complex and dynamic energy transition also correlates with higher systemic risk. These findings suggest that while energy diversification is a goal of sustainability, it may entail short-term instability. The study contributes to the understanding of how structural transformations in energy systems interact with financial vulnerabilities in liberalized electricity markets. Full article

This study discusses subjective aspects of the commodification of healthcare from an ethno-class perspective using narrative analysis of patient stories. We hypothesize that the objective social hierarchy of resources, together with a certain degree of individual agency, structure the patients’ strategies of coping with the public–private “maze” of the healthcare system. The findings show different coping strategies indicating three different ethno-class ‘patient-selves’: The dominant ‘Neo-Liberal Self’, prevalent among the upper middle-class (mostly Ashkenazi Jews) that expresses contempt of the public system, and an individual hero-quest story maneuvering between the private and the public. The ‘troubled’ patient-self of the low-middle and working classes (mainly Mizrahi Jews and Arabs) also expresses negative impressions of the public system, but it is drawn to sadness, fear of being lost, and a longing for a lost ‘logic of care’. Finally, a ‘communal alternative self’ among the Arab lower classes seeks personal solutions through social networks that include local health providers while crossing barriers between private and public sectors. All selves show some degree of neoliberal values, but the first ‘patient-self’ implies a sense of social mastery while the other two attest to the agency and even resistance of patients facing structural barriers and scarce resources. Full article