This study applies an integrated water–energy–food (WEF) nexus approach to melon and grape value chains, combining life cycle assessment, water footprinting (blue/green/grey), carbon footprint, and exergy analysis within a circular economy framework. Türkiye, the fourth-largest melon producer (~1.7 Mt/yr) with over 80 indigenous grape cultivars, serves as the primary case study, supplemented by global data. In the wine chain, cultivation (37%) and glass packaging (28%) dominate global warming potential (GWP), with a baseline of 1.38 kg CO2eq per 0.75 L bottle (ReCiPe 2016-H). Recovering pomace bioethanol, polyphenolic extracts, grape seed oil, and tartaric acid in a circular economy scenario lowers the footprint to 1.12 kg CO2eq (−19%). Turkish wine grapes exhibit blue-water shares of 38–41%, well above the global 25%, reflecting irrigation reliance in semi-arid Anatolia (Elazığ, Diyarbakır, Cappadocia). Exergy analysis identifies refrigeration as the top energy sink (280 MJ/t grapes, 32%) and primary exergy destruction site (193 MJ/t; second-law efficiency: 31%). Fermentation records the lowest exergy efficiency (28%) due to the irreversibility of sugar-to-ethanol conversion. These findings demonstrate that combining WEF nexus management with circular bioeconomy strategies can substantially reduce the overall environmental burden, particularly in water-stressed agricultural regions.
The accumulation of post-consumer cotton textile waste brings environmental challenges and opportunities for resource recovery. In this work, cotton waste was valorized into nitrocellulose via a pure nitration method, and its potential as a multifunctional material was systematically assessed. Response Surface Methodology (RSM) was used to optimize the process parameters with a Box-Behnken design, and the results indicated that nitric acid concentration was the most important parameter affecting nitrogen incorporation. The optimized process produced nitrocellulose with a Nitrogen content of 11.17%, as confirmed by CHNS analysis. However, the FTIR results confirmed that the nitrocellulose was successfully nitrated, as evidenced by the nitro group absorption bands. The produced nitrocellulose was evaluated in various applications, including pyrotechnic green mixtures, adhesive systems, and film production. Gas emission analysis indicated a nitrogen-rich and comparatively cleaner combustion profile. The adhesive test showed moderate bonding to cellulosic materials, whereas the tensile test of films showed a high tensile strength of 60.8–65.8 MPa. The findings indicate that multifunctional nitrocellulose can be successfully produced from post-consumer cotton waste, providing a viable alternative to textile waste recycling methods and adding to efforts to build a sustainable circular economy.
This research presents a comprehensive mooring design flow for a pendulum-based wave energy converter, including the design of extreme and operational sea states, a step-by-step mooring optimization, and a code check for Ultimate Limit State (ULS), Accidental Limit State (ALS), and Fatigue Limit State (FLS) based on the DNV standard. The numerical model built in OrcaFlex was validated through an experimental campaign and used for mooring design. Finally, a 3-leg hybrid mooring system consisting of elastic ropes and catenaries was obtained. Its comparison with the original design demonstrates a production increase of at least 20.7%, and the durability of the mooring system was also improved, mainly due to pretension and fairlead position adjustments. Besides, the safety code check results illustrate that fatigue damage functions as the primary threat for such a pitch-dominated device, indicating the importance of considering fatigue damage in preliminary design to avoid undesired mooring with high service life in ULS while significantly low design life in FLS. This work provides a comprehensive reference for future mooring design of the WECs that operate mainly on pitch motion, and the findings contribute to the research toward practical application of such wave energy technologies in rotating mass.
Regional carbon equity reflects the spatial alignment between carbon-emission responsibility and ecological carrying capacity, and represents an important dimension for understanding the distributive consequences of low-carbon transitions. As the digital economy becomes increasingly embedded in resource allocation, technological innovation, and environmental governance, whether and how it reshapes regional carbon equity remains insufficiently examined. Using panel data for 281 Chinese cities from 2010 to 2023, this study constructs a city-level carbon equity index and employs two-way fixed-effects models, mechanism tests, and a spatial Durbin model to investigate the effect of the digital economy on carbon equity, its transmission channels, and its spatial spillover effects. The results show that carbon equity in Chinese cities has improved slowly over time, although regional disparities remain pronounced and significant “high–high” and “low–low” spatial clustering patterns persist. The digital economy significantly improves urban carbon equity, with the strongest effect observed in central China. Mechanism tests indicate that the digital economy enhances carbon equity mainly by promoting industrial structure upgrading, stimulating green technological innovation, and strengthening market integration. Further spatial analysis shows that the digital economy improves carbon equity within local cities but exerts a negative spillover effect on neighboring cities, revealing a spatial pattern of “local promotion and neighboring suppression”. This study extends the literature on the environmental consequences of the digital economy by introducing a regional carbon equity perspective. It provides policy implications for optimizing the spatial allocation of digital resources, improving interregional coordination in low-carbon governance, and advancing a more equitable low-carbon transition.
