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Search Results (247)

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33 pages, 870 KiB  
Article
Decarbonizing Urban Transport: Policies and Challenges in Bucharest
by Adina-Petruța Pavel and Adina-Roxana Munteanu
Future Transp. 2025, 5(3), 99; https://doi.org/10.3390/futuretransp5030099 (registering DOI) - 1 Aug 2025
Abstract
Urban transport is a key driver of greenhouse gas emissions in Europe, making its decarbonization essential to achieving EU climate neutrality targets. This study examines how European strategies, such as the Green Deal, the Sustainable and Smart Mobility Strategy, and the Fit for [...] Read more.
Urban transport is a key driver of greenhouse gas emissions in Europe, making its decarbonization essential to achieving EU climate neutrality targets. This study examines how European strategies, such as the Green Deal, the Sustainable and Smart Mobility Strategy, and the Fit for 55 package, are reflected in Romania’s transport policies, with a focus on implementation challenges and urban outcomes in Bucharest. By combining policy analysis, stakeholder mapping, and comparative mobility indicators, the paper critically assesses Bucharest’s current reliance on private vehicles, underperforming public transport satisfaction, and limited progress on active mobility. The study develops a context-sensitive reform framework for the Romanian capital, grounded in transferable lessons from Western and Central European cities. It emphasizes coordinated metropolitan governance, public trust-building, phased car-restraint measures, and investment alignment as key levers. Rather than merely cataloguing policy intentions, the paper offers practical recommendations informed by systemic governance barriers and public attitudes. The findings will contribute to academic debates on urban mobility transitions in post-socialist cities and provide actionable insights for policymakers seeking to operationalize EU decarbonization goals at the metropolitan scale. Full article
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13 pages, 1428 KiB  
Article
Heavy Metals in Infant Clothing: Assessing Dermal Exposure Risks and Pathways for Sustainable Textile Policies
by Mei Xiong, Daolei Cui, Yiping Cheng, Ziya Ma, Chengxin Liu, Chang’an Yan, Lizhen Li and Ping Xiang
Toxics 2025, 13(8), 622; https://doi.org/10.3390/toxics13080622 - 25 Jul 2025
Viewed by 315
Abstract
Infant clothing represents a critical yet overlooked exposure pathway for heavy metals, with significant implications for child health and sustainable consumption. This study investigates cadmium (Cd) and chromium (Cr) contamination in 33 textile samples, integrating in vitro bioaccessibility assays, cytotoxicity analysis, and risk [...] Read more.
Infant clothing represents a critical yet overlooked exposure pathway for heavy metals, with significant implications for child health and sustainable consumption. This study investigates cadmium (Cd) and chromium (Cr) contamination in 33 textile samples, integrating in vitro bioaccessibility assays, cytotoxicity analysis, and risk assessment models to evaluate dermal exposure risks. Results reveal that 80% of samples exceeded OEKO-TEX Class I limits for As (mean 1.01 mg/kg), Cd (max 0.25 mg/kg), and Cr (max 4.32 mg/kg), with infant clothing showing unacceptable hazard indices (HI = 1.13) due to Cd (HQ = 1.12). Artificial sweat extraction demonstrated high bioaccessibility for Cr (37.8%) and Ni (28.5%), while keratinocyte exposure triggered oxidative stress (131% ROS increase) and dose-dependent cytotoxicity (22–59% viability reduction). Dark-colored synthetic fabrics exhibited elevated metal loads, linking industrial dye practices to health hazards. These findings underscore systemic gaps in textile safety regulations, particularly for low- and middle-income countries reliant on cost-effective apparel. We propose three policy levers: (1) tightening infant textile standards for Cd/Cr, (2) incentivizing non-toxic dye technologies, and (3) harmonizing global labeling requirements. By bridging toxicological evidence with circular economy principles, this work advances strategies to mitigate heavy metal exposure while supporting Sustainable Development Goals (SDGs) 3 (health), 12 (responsible consumption), and 12.4 (chemical safety). Full article
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23 pages, 346 KiB  
Article
Thirst for Change in Water Governance: Overcoming Challenges for Drought Resilience in Southern Europe
by Eleonora Santos
Water 2025, 17(15), 2170; https://doi.org/10.3390/w17152170 - 22 Jul 2025
Viewed by 264
Abstract
This article investigates the institutional and informational foundations of water governance in Southern Europe amid escalating climate stress. Focusing on Portugal, Spain, Italy, and Greece, it develops a multi-level analytical framework to explore how information asymmetries and governance fragmentation undermine coordinated responses to [...] Read more.
This article investigates the institutional and informational foundations of water governance in Southern Europe amid escalating climate stress. Focusing on Portugal, Spain, Italy, and Greece, it develops a multi-level analytical framework to explore how information asymmetries and governance fragmentation undermine coordinated responses to water scarcity. Integrating theories of information economics, polycentric governance, and critical institutionalism, this study applies a stylized economic model and comparative institutional analysis to assess how agents—such as farmers, utilities, regulators, and civil society—respond to varying incentives, data access, and coordination structures. Using secondary data, normalized indicators, and scenario-based simulations, the model identifies three key structural parameters—institutional friction (θi), information cost (βi), and incentive strength (αi)—as levers for governance reform. The simulations are stylized and not empirically calibrated, serving as heuristic tools rather than predictive forecasts. The results show that isolated interventions yield limited improvements, while combined reforms significantly enhance both equity and effectiveness. Climate stress simulations further reveal stark differences in institutional resilience, with Greece and Italy showing systemic fragility and Portugal emerging as comparatively robust. This study contributes a flexible, policy-relevant tool for diagnosing governance capacity and informing reform strategies while also underscoring the need for integrated, equity-oriented approaches to adaptive water governance. Full article
21 pages, 1620 KiB  
Article
Guiding the Unseen: A Systems Model of Prompt-Driven Agency Dynamics in Generative AI-Enabled VR Serious Game Design
by Chenhan Jiang, Shengyu Huang and Tao Shen
Systems 2025, 13(7), 576; https://doi.org/10.3390/systems13070576 - 12 Jul 2025
Viewed by 423
Abstract
Generative Artificial Intelligence (GenAI)-assisted Virtual Reality (VR) heritage serious game design constitutes a complex adaptive socio-technical system in which natural language prompts act as control levers shaping designers’ cognition and action. However, the systemic effects of prompt type on agency construction, decision boundaries, [...] Read more.
Generative Artificial Intelligence (GenAI)-assisted Virtual Reality (VR) heritage serious game design constitutes a complex adaptive socio-technical system in which natural language prompts act as control levers shaping designers’ cognition and action. However, the systemic effects of prompt type on agency construction, decision boundaries, and process strategy remain unclear. Treating the design setting as adaptive, we captured real-time interactions by collecting think-aloud data from 48 novice designers. Nine prompt categories were extracted and their cognitive effects were systematically analyzed through the Repertory Grid Technique (RGT), principal component analysis (PCA), and Ward clustering. These analyses revealed three perception profiles: tool-based, collaborative, and mentor-like. Strategy coding of 321 prompt-aligned utterances showed cluster-specific differences in path length, first moves, looping, and branching. Tool-based prompts reinforced boundary control through short linear refinements; collaborative prompts sustained moderate iterative enquiry cycles; mentor-like prompts triggered divergent exploration via self-loops and frequent jumps. We therefore propose a stage-adaptive framework that deploys mentor-like prompts for ideation, collaborative prompts for mid-phase iteration, and tool-based prompts for final verification. This approach balances creativity with procedural efficiency and offers a reusable blueprint for integrating prompt-driven agency modelling into GenAI design workflows. Full article
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30 pages, 435 KiB  
Review
Vaccination as a Game: Behavioural Dynamics, Network Effects, and Policy Levers—A Comprehensive Review
by Pedro H. T. Schimit, Abimael R. Sergio and Marco A. R. Fontoura
Mathematics 2025, 13(14), 2242; https://doi.org/10.3390/math13142242 - 10 Jul 2025
Viewed by 424
Abstract
Classical epidemic models treat vaccine uptake as an exogenous parameter, yet real-world coverage emerges from strategic choices made by individuals facing uncertain risks. During the last two decades, vaccination games, which combine epidemic dynamics with game theory, behavioural economics, and network science, have [...] Read more.
Classical epidemic models treat vaccine uptake as an exogenous parameter, yet real-world coverage emerges from strategic choices made by individuals facing uncertain risks. During the last two decades, vaccination games, which combine epidemic dynamics with game theory, behavioural economics, and network science, have become a very important tool for analysing this problem. Here, we synthesise more than 80 theoretical, computational, and empirical studies to clarify how population structure, psychological perception, pathogen complexity, and policy incentives interact to determine vaccination equilibria and epidemic outcomes. Papers are organised along five methodological axes: (i) population topology (well-mixed, static and evolving networks, multilayer systems); (ii) decision heuristics (risk assessment, imitation, prospect theory, memory); (iii) additional processes (information diffusion, non-pharmacological interventions, treatment, quarantine); (iv) policy levers (subsidies, penalties, mandates, communication); and (v) pathogen complexity (multi-strain, zoonotic reservoirs). Common findings across these studies are that voluntary vaccination is almost always sub-optimal; feedback between incidence and behaviour can generate oscillatory outbreaks; local network correlations amplify free-riding but enable cost-effective targeted mandates; psychological distortions such as probability weighting and omission bias materially shift equilibria; and mixed interventions (e.g., quarantine + vaccination) create dual dilemmas that may offset one another. Moreover, empirical work surveys, laboratory games, and field data confirm peer influence and prosocial motives, yet comprehensive model validation remains rare. Bridging the gap between stylised theory and operational policy will require data-driven calibration, scalable multilayer solvers, and explicit modelling of economic and psychological heterogeneity. This review offers a structured roadmap for future research on adaptive vaccination strategies in an increasingly connected and information-rich world. Full article
(This article belongs to the Special Issue Mathematical Epidemiology and Evolutionary Games)
26 pages, 547 KiB  
Article
Exploring Resilience Through a Systems Lens: Agile Antecedents in Projectified Organizations
by Nuša Širovnik and Igor Vrečko
Systems 2025, 13(7), 559; https://doi.org/10.3390/systems13070559 - 9 Jul 2025
Viewed by 329
Abstract
As organizations become increasingly projectified, safeguarding the resilience of project professionals and teams emerges as a critical organizational challenge. Adopting a systems lens, we investigate how agile mindsets and agile practices function as systemic antecedents of resilience at the individual and team levels. [...] Read more.
As organizations become increasingly projectified, safeguarding the resilience of project professionals and teams emerges as a critical organizational challenge. Adopting a systems lens, we investigate how agile mindsets and agile practices function as systemic antecedents of resilience at the individual and team levels. Eleven semi-structured interviews with experienced project managers, product owners, and team members from diverse industries were analyzed through inductive thematic coding and system mapping. The findings show that mindset supplies psychological resources—self-efficacy, openness and a learning orientation—while practices such as team autonomy, iterative delivery and transparent communication provide structural routines; together they trigger five interlocking mechanisms: empowerment, fast responsiveness, holistic team dynamics, stakeholder-ecosystem engagement and continuous learning. These mechanisms reinforce one another in feedback loops that boost a project system’s adaptive capacity under volatility. The synergy of mindset and practices is especially valuable in hybrid or traditionally governed projects, where cognitive agility offsets structural rigidity. This study offers the first multi-level, systems-based explanation of agile antecedents of resilience and delivers actionable levers for executives, transformation leaders, project professionals, and HR specialists aiming to sustain talent performance in turbulent contexts. Full article
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11 pages, 1002 KiB  
Article
Unveiling the Evolution of MWC 728: Non-Conservative Mass Transfer in an FS CMa Binary
by Nadezhda L. Vaidman, Serik A. Khokhlov and Aldiyar T. Agishev
Galaxies 2025, 13(4), 78; https://doi.org/10.3390/galaxies13040078 - 7 Jul 2025
Viewed by 397
Abstract
We combine corrected Gaia DR3 astrometry with non-conservative MESA modelling to retrace the evolution of the FS-CMa binary MWC 728. The revised parallax sets the distance at d=1.2±0.1 kpc, leading—after Monte-Carlo error propagation—to luminosities of [...] Read more.
We combine corrected Gaia DR3 astrometry with non-conservative MESA modelling to retrace the evolution of the FS-CMa binary MWC 728. The revised parallax sets the distance at d=1.2±0.1 kpc, leading—after Monte-Carlo error propagation—to luminosities of log(L/L)acc=2.6±0.1 and log(L/L)don=1.5±0.1, corresponding to the accretor and donor, respectively. A fiducial binary track that starts with Mdon=3.6±0.1M, Macc=1.8±0.1M, and P0=21.0±0.2 d reproduces the observations provided the Roche-lobe overflow, which is moderately non-conservative: only 39% of the transferred mass is retained by the accretor, while the remainder leaves the system via (i) a fast isotropic wind from the donor (α=0.01), (ii) isotropic re-emission near the accretor (β=0.45), and (iii) outflow into a circumbinary torus (δ=0.15, lever arm γ=1.3). These channels remove sufficient angular momentum to expand the orbit to the observed Pobs=27.5±0.1 d while sustaining the dusty circumbinary outflow. At t223 Myr, the model matches every current observable: Mdon=1.30±0.05M, Macc=2.67±0.05M, mass ratio q=2.0±0.1, and an ongoing transfer rate of M˙(1±0.3)×106Myr1. MWC 728 thus serves as a benchmark intermediate-mass binary for testing how non-conservative outflows regulate angular-momentum loss and orbital growth. Full article
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26 pages, 5512 KiB  
Article
Optimal Design for a Novel Compliant XY Platform Integrated with a Hybrid Double Symmetric Amplifier Comprising One-Lever and Scott–Russell Mechanisms Arranged in a Perpendicular Series Layout for Vibration-Assisted CNC Milling
by Minh Phung Dang, Anh Kiet Luong, Hieu Giang Le and Chi Thien Tran
Micromachines 2025, 16(7), 793; https://doi.org/10.3390/mi16070793 - 3 Jul 2025
Viewed by 663
Abstract
Compliant mechanisms are often utilized in precise positioning systems but have not been thoroughly examined in vibration-aided fine CNC machining. This study aims to develop a new 02-DOF flexure stage for vibration-aided fine CNC milling. A hybrid displacement amplifier, featuring a two-lever mechanism, [...] Read more.
Compliant mechanisms are often utilized in precise positioning systems but have not been thoroughly examined in vibration-aided fine CNC machining. This study aims to develop a new 02-DOF flexure stage for vibration-aided fine CNC milling. A hybrid displacement amplifier, featuring a two-lever mechanism, two Scott–Russell mechanisms, and a parallel leading mechanism, was integrated into a symmetric perpendicular series configuration to create an innovative design. The pseudo-rigid body model (PRBM), Lagrangian approach, finite element analysis (FEA), and Firefly optimization algorithm were employed to develop, verify, and optimize the quality response of the new positioner. The PRBM and Lagrangian methods were used to construct an analytical model, while finite element analysis was used to validate the theoretical solution. The primary natural frequency results from theoretical and FEM methods were 318.16 Hz and 308.79 Hz, respectively. The difference between these techniques was 3.04%, demonstrating a reliable modelling strategy. The Firefly optimization approach applied mathematical equations to enhance the key design factors of the mechanism. The prototype was then built, revealing an error of 7.23% between the experimental and simulated frequencies of 331.116 Hz and 308.79 Hz, respectively. The specimen was subsequently mounted on the fabricated optimization positioner, and vibration-assisted fine CNC milling was performed at 100–1000 Hz. At 400 Hz, the specimen achieved ideal surface roughness with a Ra value of 0.187 µm. The developed design is a potential structure that generates non-resonant frequency power for vibration-aided fine CNC milling. Full article
(This article belongs to the Section E:Engineering and Technology)
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43 pages, 1191 KiB  
Review
Biomimetic Strategies for Nutraceutical Delivery: Advances in Bionanomedicine for Enhanced Nutritional Health
by Vicente Javier Clemente-Suárez, Alvaro Bustamante-Sanchez, Alejandro Rubio-Zarapuz, Alexandra Martín-Rodríguez, José Francisco Tornero-Aguilera and Ana Isabel Beltrán-Velasco
Biomimetics 2025, 10(7), 426; https://doi.org/10.3390/biomimetics10070426 - 1 Jul 2025
Viewed by 769
Abstract
Background: Biomimetic strategies have gained increasing attention for their ability to enhance the delivery, stability, and functionality of nutraceuticals by emulating natural biological systems. However, the literature remains fragmented, often focusing on isolated technologies without integrating regulatory, predictive, or translational perspectives. Objective: This [...] Read more.
Background: Biomimetic strategies have gained increasing attention for their ability to enhance the delivery, stability, and functionality of nutraceuticals by emulating natural biological systems. However, the literature remains fragmented, often focusing on isolated technologies without integrating regulatory, predictive, or translational perspectives. Objective: This review aims to provide a comprehensive and multidisciplinary synthesis of biomimetic and bio-inspired nanocarrier strategies for nutraceutical delivery, while identifying critical gaps in standardization, scalability, and clinical translation. Results: We present a structured classification matrix that maps biomimetic delivery systems by material type, target site, and bioactive compound class. In addition, we analyze predictive design tools (e.g., PBPK modeling and AI-based formulation), regulatory frameworks (e.g., EFSA, FDA, and GSRS), and risk-driven strategies as underexplored levers to accelerate innovation. The review also integrates ethical and environmental considerations, and highlights emerging trends such as multifunctional hybrid systems and green synthesis routes. Conclusions: By bridging scientific, technological, and regulatory domains, this review offers a novel conceptual and translational roadmap to guide the next generation of biomimetic nutraceutical delivery systems. It addresses key bottlenecks and proposes integrative strategies to enhance design precision, safety, and scalability. Full article
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24 pages, 9809 KiB  
Article
Assessing Coastal Degradation Through Spatiotemporal Earth Observation Data Cubes Analytics and Multidimensional Visualization
by Ioannis Kavouras, Ioannis Rallis, Nikolaos Bakalos and Anastasios Doulamis
J. Mar. Sci. Eng. 2025, 13(7), 1239; https://doi.org/10.3390/jmse13071239 - 27 Jun 2025
Viewed by 225
Abstract
Coastal and maritime regions and their entities face accelerated degradation due to the combined effects of environmental stressors and anthropogenic activities. Coastal degradation can be identified, visualized and estimated through periodic monitoring over a region of interest using earth observation, climate, meteorological, seasonal, [...] Read more.
Coastal and maritime regions and their entities face accelerated degradation due to the combined effects of environmental stressors and anthropogenic activities. Coastal degradation can be identified, visualized and estimated through periodic monitoring over a region of interest using earth observation, climate, meteorological, seasonal, waves, sea level rising, and other ocean- and maritime-related datasets. Usually, these datasets are provided through different sources, in different structures or data types; in many cases, a complete dataset can be large in size and needs some kind of preprocessing (information filtering) before use in the intended application. Recently, the term data cube introduced in the scientific community and frameworks like Google Earth Engine and Open Data Cubes have emerged as a solution to earth observation data harmonization, federation, and exchange framework; however, these sources either completely lack the ability to process climate, meteorological, waves, sea lever rising, etc., data from open sources, like CORDEX and WCRP, or preprocessing is required. This study describes and utilizes the Ocean-DC framework for modular earth observation and other data types to resolve major big data challenges. Compared to the already existing approaches, the Ocean-DC framework harmonizes several types of data and generates ready-to-use data cubes products, which can be merged together to produce high-dimensionality visualization products. To prove the efficiency of the Ocean-DC framework, a case study at Crete Island, emphasizing the Port of Heraklion, demonstrates the practical utility by revealing degradation trends via time-series analysis of several related remote sensing indices calculated using the Ocean-DC framework. The results show a significant reduction in processing time (up to 89%) compared to traditional remote sensing approaches and optimized data storage management, proving its value as a scalable solution for environmental resilience, highlighting its potential use in early warning systems and decision support systems for sustainable coastal infrastructure management. Full article
(This article belongs to the Section Ocean Engineering)
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29 pages, 1114 KiB  
Article
Advancing Sustainable Digital Transformations Through HRIS Effectiveness: Examining the Role of Information Quality, Executives’ Innovativeness, and Staff IT Capabilities via IS Ambidexterity
by Muhammad Shahid Siddique, Md. Lazim Bin Mohd Zin and Saiful Azizi bin Ismail
Sustainability 2025, 17(13), 5784; https://doi.org/10.3390/su17135784 - 24 Jun 2025
Viewed by 584
Abstract
In the face of accelerating digital transformation and AI-driven innovations in the post-COVID-19 era, the effectiveness of Human Resource Information Systems (HRIS) is critical to organizational resilience and sustainable digital transformation in highly regulated sectors. This study examines how information quality, executive innovativeness, [...] Read more.
In the face of accelerating digital transformation and AI-driven innovations in the post-COVID-19 era, the effectiveness of Human Resource Information Systems (HRIS) is critical to organizational resilience and sustainable digital transformation in highly regulated sectors. This study examines how information quality, executive innovativeness, and staff IT capabilities influence HRIS effectiveness and evaluates the mediating role of Information System (IS) Ambidexterity, defined as an organization’s ability to explore and exploit its IS resources concurrently. By confirming the impact of organizational enablers on HRIS effectiveness, the study provides theoretical grounding for digital transformation strategies rooted in Resource-Based View (RBV) and Dynamic Capabilities Theory (DCT). Partial Least Squares Structural Equation Modeling (PLS-SEM) using SmartPLS was employed for its strength in modeling complex relationships and validating latent constructs in organizational contexts. Empirical data were gathered from 157 HR leaders across financial institutions in Pakistan. The results confirm that the identified enablers significantly impact both IS Ambidexterity and HRIS effectiveness and also emerge as strategic levers for building resilient, data-driven HRIS frameworks. IS Ambidexterity, a relatively underexplored construct in information systems research, enhances the strategic contribution of HRIS by serving as a dynamic capability that enables organizations to adapt and create sustained value in evolving digital environments. HRIS effectiveness contributes to efficiency, agility, strategic responsiveness, and cost optimization in financial institutions. The findings contribute to theory by integrating IS enablers with dynamic capability mediation, enriching the RBV-DCT interplay. This study provides evidence-based insights for developing economies pursuing sustainable digital transformations. Full article
(This article belongs to the Special Issue Sustainable Digital Transformation and Corporate Practices)
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26 pages, 6795 KiB  
Article
Integrated Analysis of Pore and Fracture Networks in Deep Coal Seams: Implications for Enhanced Reservoir Stimulation
by Kaiqi Leng, Baoshan Guan, Chen Jiang and Weidong Liu
Energies 2025, 18(13), 3235; https://doi.org/10.3390/en18133235 - 20 Jun 2025
Viewed by 238
Abstract
This study systematically investigates the pore–fracture architecture of deep coal seams in the JiaTan (JT) block of the Ordos Basin using an integrated suite of advanced techniques, including nuclear magnetic resonance (NMR), high-pressure mercury intrusion, low-temperature nitrogen adsorption, low-pressure carbon dioxide adsorption, and [...] Read more.
This study systematically investigates the pore–fracture architecture of deep coal seams in the JiaTan (JT) block of the Ordos Basin using an integrated suite of advanced techniques, including nuclear magnetic resonance (NMR), high-pressure mercury intrusion, low-temperature nitrogen adsorption, low-pressure carbon dioxide adsorption, and micro-computed tomography (micro-CT). These complementary methods enable a quantitative assessment of pore structures spanning nano- to microscale dimensions. The results reveal a pore system overwhelmingly dominated by micropores—accounting for more than 98% of the total pore volume—which play a central role in coalbed methane (CBM) storage. Microfractures, although limited in volumetric proportion, markedly enhance permeability by forming critical flow pathways. Together, these features establish a dual-porosity system that governs methane transport and recovery in deep coal reservoirs. The multiscale characterization employed here proves essential for resolving reservoir heterogeneity and designing effective stimulation strategies. Notably, enhancing methane desorption in micropore-rich matrices and improving fracture connectivity are identified as key levers for optimizing deep CBM extraction. These insights offer a valuable foundation for the development of deep coalbed methane (DCBM) resources in the Ordos Basin and similar geological settings. Full article
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19 pages, 2084 KiB  
Article
Assessment of Uneven Wear of Freight Wagon Brake Pads
by Sergii Panchenko, Juraj Gerlici, Alyona Lovska and Vasyl Ravlyuk
Appl. Sci. 2025, 15(12), 6860; https://doi.org/10.3390/app15126860 - 18 Jun 2025
Viewed by 344
Abstract
This study deals with the problem of uneven wear of brake pads of wagons caused by a set of structural, dynamic, technological and operational factors. It has been found that an uneven distribution of the brake pad pressure force leads to higher maintenance [...] Read more.
This study deals with the problem of uneven wear of brake pads of wagons caused by a set of structural, dynamic, technological and operational factors. It has been found that an uneven distribution of the brake pad pressure force leads to higher maintenance costs and lower braking efficiency. The main causes of uneven wear are worn kinetostatic units, differences in the geometric parameters of pads, and imperfections in the lever transmission design. A method for optimizing the distribution of the pressure force using weight coefficients and the Lagrange function has been developed; it reduces the uneven wear of brake pads to 8–10% compared to that of a typical wagon bogie brake system, which is 20–35%. The experiments conducted have shown that for a mileage of 74,400 km and with the air distributor in empty mode, the wear of the pads is 19.6–28 mm, while in the loaded mode it amounts to 27.53–38.04 mm. The stress state of brake pads was determined with consideration of the weight coefficients. It was found that for abnormal wear of brake pads, their strength is not observed. The strength of the wheel when interacting with an abnormally worn pad has also been assessed. The resulting stresses are 1.5% higher than those that occur when the wheel interacts with the pad with nominal dimensions. The results of the research will contribute to the database of developments to be used for designing of modern structures of tribotechnical pairs of rolling stock and increasing the efficiency of railway transport. Full article
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30 pages, 5100 KiB  
Article
Design and Optimization of a Novel Compliant Z-Positioner for the Nanoindentation Testing Device
by Minh Phung Dang, Thanh Dat Le, Hieu Giang Le and Chi Thien Tran
Machines 2025, 13(6), 485; https://doi.org/10.3390/machines13060485 - 3 Jun 2025
Viewed by 327
Abstract
Compliant mechanisms are extensively utilized in precise positioning systems. This work presents a novel compliant fine Z-positioner for directing the indenter in a nanoindentation testing positioning system. Initially, the suggested positioner consists of a novel hybrid symmetric compliant displacement amplifier of four-lever and [...] Read more.
Compliant mechanisms are extensively utilized in precise positioning systems. This work presents a novel compliant fine Z-positioner for directing the indenter in a nanoindentation testing positioning system. Initially, the suggested positioner consists of a novel hybrid symmetric compliant displacement amplifier of four-lever and Scott Russell structures combined with a parallel guiding mechanism. Subsequently, a static–dynamic characteristic of the proposed positioner is modeled by the pseudo-rigid body method and the Lagrange technique. Based on the FEA results, the parasitic motion error of the developed fine Z-positioner was 0.0956%. Thirdly, the analytical result was verified by FEA analysis, and the error between the two methods was 0.5869%. Therefore, the proposed analytical approach was reliable for quickly assessing the output response of the proposed positioner. Finally, to enhance the quality of the proposed structure’s response, the main design variables of the fine Z-positioner are optimized using the Firefly algorithm. The optimal findings indicated that the first natural frequency occurs at around 220.16 Hz. The imprecision between the optimal result and the FEA result was 9.67%. The analytical results are in close agreement with the confirmed FEA result. The prototype was manufactured by the computerized numerical milling method. The inexactness between the FEA outcome and the experimentation outcome was 11.04%. Based on the FEA and experiment results, displacement amplification proportions were 6.8725 and 8, respectively. In addition, the experimental results demonstrated a good linear relationship for guiding mechanisms in nanoindentation testing positioning systems. Full article
(This article belongs to the Special Issue Optimization and Design of Compliant Mechanisms)
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25 pages, 2726 KiB  
Article
Breaking Silos: A Systemic Portfolio Approach and Digital Tool for Collaborative Urban Decarbonisation
by Manuel Alméstar, Sara Romero-Muñoz and Nieves Mestre
Sustainability 2025, 17(11), 5145; https://doi.org/10.3390/su17115145 - 3 Jun 2025
Viewed by 809
Abstract
Urban decarbonisation requires governance models that overcome the fragmentation and rigidity of traditional urban planning. This article presents a systemic and digital framework for managing urban decarbonisation portfolios aligned with the EU Mission for Climate-Neutral and Smart Cities. Grounded in systems thinking and [...] Read more.
Urban decarbonisation requires governance models that overcome the fragmentation and rigidity of traditional urban planning. This article presents a systemic and digital framework for managing urban decarbonisation portfolios aligned with the EU Mission for Climate-Neutral and Smart Cities. Grounded in systems thinking and portfolio theory, this study develops an analytical taxonomy and an interactive digital tool to support strategic coordination, multistakeholder collaboration, and adaptive decision-making. The framework is empirically validated through the case of Madrid’s Climate City Contract, demonstrating its functionality and transferability. Using a mixed-method approach—combining co-creation workshops, interviews, document analysis, and iterative prototyping—this research maps interdependencies among projects, actors, and levers of change. The digital tool enables real-time visualisation of collaboration patterns, gaps, and synergies, enhancing strategic foresight and coordination capacity. Findings reveal that 75% of initiatives in Madrid’s CCC address climate adaptation, 80.36% are linked to knowledge generation, and key anchor projects serve as integrative hubs within the portfolio. This study concludes that the portfolio approach strengthens systemic innovation and reflexive governance by integrating digital infrastructures with collaborative planning processes. While challenges persist—including data integration, institutional capacity, and political dynamics—this research offers a replicable methodology for embedding mission-oriented strategies into urban governance. The digital portfolio emerges as a complementary governance tool that enhances transparency, organisational learning, and alignment across governance levels. Full article
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