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Preparation and characterization of biopolymer-based packaging materials have significantly gained importance because of sustainability, biodegradability, and eco-friendly nature. In this study, novel wheat gluten (WG)/cloisite 30B (C30B) organoclay-based bionanocomposite (BNC) films were prepared by solution casting method at various C30B concentrations (5%, 10%, and 15%). X-ray diffraction and field emission scanning electron microscopy revealed intercalation/exfoliation of C30B sheets into the WG matrix. WG-C30B 10% film was thermostable. It showed low surface roughness along with higher water barrier properties and surface hydrophobicity. The tensile strength values of WG and WG-C30B 10% films were found to be 0.7 +/- 0.02 and 1.11 +/- 0.01, respectively, indicating improvement in mechanical properties. WG-C30B 10% film demonstrated antibacterial activity against both Staphylococcus aureus and Salmonella enterica. Shelf life of green grapes was monitored under different conditions: 4 degrees C, ambient conditions, and 42 degrees C. WG-C30B 10% film proved effective in extending shelf life up to 18 days under ambient conditions. More than 50% of the bionanocomposite films were degraded in agricultural soil within 2 weeks, while completely degraded in sewage sludge soil after a few days. WG-C30B 10% film appeared to be promising regarding the demonstrated physico-chemical and antibacterial properties. This report would be useful in preparing biodegradable biopolymer-based packaging materials.

期刊论文 2025-04-15 DOI: 10.1007/s13399-025-06846-5 ISSN: 2190-6815

A cast-in-place pile foundation, widely utilized in the permafrost regions of the Qinghai-Tibet Plateau, boasts superior load-bearing capacity, effectively mitigating the seasonal freeze-thaw effects. In permafrost regions, substantial pile foundation load-bearing capacity is provided by freezing strength, with the freezing strength determined by the temperature of the surrounding permafrost. In modern times, global warming has been causing permafrost degradation, posing a risk to the safety of existing pile foundations. In order to maintain the stability of these foundations, it is crucial to release excess ground heat, considering the temperature-dependent freezing strength of the ground to pile shaft. Two-phase closed thermosyphons (TPCTs) have demonstrated strong performance in the realm of cooling permafrost engineering. In this study, TPCTs were utilized to mitigate the impact of permafrost degradation by installing them around a concrete pile in order to cool the foundation ground. Following this installation, a model experiment was carried out, which ingeniously focused on analyzing the cooling performance, the process of cold energy dissipation, and the cooling scope of the TPCT pile. The study's findings indicate that the operation time of the TPCT pile accounted for about 50% of the entire freeze-thaw cycle. This device could effectively cool the surrounding foundation soil within a specified area. The TPCT pile exhibited a low temperature advantage of 0.36 degrees C in comparison with the scenario without TPCT in terms of surrounding geotemperature, although it experienced significant cold energy dissipation. The conclusions drawn from this study have significant value for maintaining piles in permafrost regions.

期刊论文 2025-03-01 DOI: 10.1061/JCRGEI.CRENG-884 ISSN: 0887-381X

Global warming accelerates permafrost degradation, compromising the reliability of critical infrastructure relied upon by over five million people daily. Additionally, permafrost thaw releases substantial methane emissions due to the thawing of swamps, further amplifying global warming and climate change and thus posing a significant threat to more than eight billion people worldwide. To mitigate this growing risk, policymakers and stakeholders need accurate predictions of permafrost thaw progression. Comprehensive physics-based permafrost models often require complex, location-specific fine-tuning, making them impractical for widespread use. Although simpler models with fewer input parameters offer convenience, they generally lack accuracy. Purely data-driven models also face limitations due to the spatial and temporal sparsity of observational data. This work develops a physics-informed machine learning framework to predict permafrost thaw rates. By integrating a physics-based model into machine learning, the framework significantly enhances the feature set, enabling models to train on higher-quality data. This approach improves permafrost thaw rate predictions, supporting more reliable decision-making for construction and infrastructure maintenance in permafrost-vulnerable regions, with a forecast horizon spanning several decades.

期刊论文 2025-01-01 DOI: 10.1109/ACCESS.2025.3573072 ISSN: 2169-3536

Permafrost, a major component of the cryosphere, is undergoing rapid degradation due to climate change, human activities, and other external disturbances, profoundly impacting ecosystems, hydroclimate, engineering geological stability, and infrastructure. In Northeast China, the thermal dynamics of Xing'an permafrost (XAP) are particularly complex, complicating the accurate assessment of its spatial extent. Many earlier mapping efforts, despite significant progress, fall short in accounting for some key local geo-environmental factors. Thus, this study introduces a new approach that incorporates four key driving factors-biotic, climatic, physiographic, and anthropogenic-by integrating multisource datasets and in situ observations. Four machine learning (ML) models [random forest (RF), support vector machine (SVM), logistic regression (LR), and extreme gradient boosting (XGB)] are applied to simulate permafrost distribution and probability, as well as to evaluate their performance. The results indicate that models' accuracy, ranked from highest to lowest, is as follows: RF (area under the curve (AUC) =0.88 and accuracy =0.81), XGB (0.86 and 0.77), LR (0.81 and 0.73), and SVM (0.76 and 0.66), with RF emerging as the most effective model for permafrost mapping in Northeast China. Analysis of the relationships between predictors and permafrost occurrence probability (POP) indicates that vegetation and snow cover exert nonlinear effects on permafrost, while human activities significantly reduce POP. Additionally, finer soil textures and higher soil organic matter content are positively correlated with increased POP. The modeling results, combined with field survey data, also show that permafrost is more prevalent in lowlands than in uplands, confirming the symbiotic relationship between permafrost and wetlands in Northeast China. This spatial variation is influenced by local microclimates, runoff patterns, and soil thermal properties. The primary sources of model error are uncertainties in the accuracy of multisource datasets at different scales and the reliability of observational data. Overall, ML models demonstrate great potential for mapping permafrost in Northeast China.

期刊论文 2025-01-01 DOI: 10.1109/TGRS.2025.3569727 ISSN: 0196-2892

The long-term stability of the cast-in-place footings in permafrost regions has received much attention due to its climate sensitivity. The current research lacks long-term data validation, especially in the context of climate change. Based on the 13-year (2011-2023) temperature and deformation monitoring data from the Qinghai-Tibet Power Transmission Line, this study investigates the characteristics of permafrost variation and its impact on the stability of tower footings under the cooling effect from thermosyphons. The results reveal that the thermosyphons effectively reduce the ground temperature around the footings. After the first freeze-thaw cycle, the soil around the tower footings completed refreezing and maintained a frozen state. In the following 13 years, the ground temperature continued to decrease due to the cooling effect of thermosyphons. The duration notably exceeded the previously predicted 5 years. The temperature reduction at the base of the footings corresponded well with the frost jacking of the tower footings and could be divided into three distinct phases. In phase 1, the ground temperature around the footings rapidly reduced, approaching that of the natural field, while the footings experienced pronounced deformation. In phase 2, the ground temperature decreased at a faster rate, and the deformation rate of the footings slowed down. In phase 3, the frost jacking of the footings gradually retarded with the decrease in base temperature. Additionally, the ground temperature differences of over 1 degrees C were observed among different tower footings, which may lead to the differential deformation among the tower footings. The ground temperature differentiation is attributed to the difference in solar radiation intensity, which is shaded by the tower structure from different directions. This study provides theoretical support and empirical accumulation for the construction and maintenance of tower footings in permafrost regions.

期刊论文 2024-10-01 DOI: 10.1016/j.accre.2024.08.002 ISSN: 1674-9278

Commercial bacterial exopolysaccharide (EPS) applications have been gaining interest; therefore, strains that provide higher yields are required for industrial-scale processes. Succinoglycan (SG) is a type of bacterial anionic exopolysaccharide produced by Rhizobium, Agrobacterium, and other soil bacterial species. SG has been widely used as a pharmaceutical, cosmetic, and food additive based on its properties as a thickener, texture enhancer, emulsifier, stabilizer, and gelling agent. An SG-overproducing mutant strain (SMC1) was developed from Sinorhizobium meliloti 1021 through N-methyl-N '-nitro-N-nitrosoguanidine (NTG) mutation, and the physicochemical and rheological properties of SMC1-SG were analyzed. SMC1 produced (22.3 g/L) 3.65-fold more SG than did the wild type. Succinoglycan (SMC1-SG) overproduced by SMC1 was structurally characterized by FT-IR and H-1 NMR spectroscopy. The molecular weights of SG and SMC1-SG were 4.20 x 10(5) and 4.80 x 10(5) Da, respectively, as determined by GPC. Based on DSC and TGA, SMC1-SG exhibited a higher endothermic peak (90.9 degrees C) than that of SG (77.2 degrees C). Storage modulus (G ') and loss modulus (G '') measurements during heating and cooling showed that SMC1-SG had improved thermal behavior compared to that of SG, with intersections at 74.9 degrees C and 72.0 degrees C, respectively. The SMC1-SG ' s viscosity reduction pattern was maintained even at high temperatures (65 degrees C). Gelation by metal cations was observed in Fe3+ and Cr3+ solutions for both SG and SMC1-SG. Antibacterial activities of SG and SMC1-SG against Escherichia coli and Staphylococcus aureus were also observed. Therefore, like SG, SMC1-SG may be a potential biomaterial for pharmaceutical, cosmetic, and food industries.

期刊论文 2024-01-01 DOI: 10.3390/polym16020244

This ground-breaking research embarks on a journey to explore the transformative capabilities of Musa acuminata fiber-reinforced epoxy composites enriched with the enchanting prowess of alumina particles. The primary goal is to provide invaluable insights into the performance and potential applications of these eco-materials. Through the skilled craftsmanship of a compression molding machine, the composites were prepared meticulously and infused with different weight percentages of alumina particles (5%, 10%, and 15%) in the epoxy matrix, along with treated and untreated Musa acuminata fibers. TBA10 samples emerged as the champions among the compositions tested, showcasing the TES and FLS at an impressive 45.78 MPa and 76.97 MPa, respectively. On the other hand, the esteemed TBA15 sample exhibited an exceptional IMS of 60.8 kJ/m(2). SEM painted a mesmerizing picture, revealing a robust bond between the reinforcement and the medium. The incorporation of Al2O3 powder resulted in significantly reduced fiber pull-outs and voids, reinforcing the composite's structural integrity. Intriguingly, the water absorption behavior of the TBA10 sample stood out, boasting a mere 24% water absorption percentage, underscoring its remarkable water-defying capabilities. The degradation of lignin occurred at higher temperatures, approximately 415 C-degrees for untreated composites (UB) and 450 C-degrees for TBA15 composites. This enhancement in thermal stability testified to the profound impact of alumina infusion. By evaluating biodegradation behavior through soil burial tests, TBA15 showcased its resilience, exhibiting minimal strength loss, with only a 9.65% reduction in TES, 15% reduction in FLS, and 6.77% reduction in IMS.

期刊论文 2024-01-01 DOI: 10.1007/s12221-023-00405-3 ISSN: 1229-9197

The amount of rainfall varies unevenly in different regions of the Qinghai-Tibet Plateau, with some regions becoming wetter and others drier. Precipitation has an important impact on the process of surface energy balance and the energy-water transfer within soils. To clarify the thermal-moisture dynamics and thermal stability of the active layer in permafrost regions under wet/dry conditions, the verified water-vapour-heat coupling model was used. Changes in the surface energy balance, energy-water transfer within the soil, and thickness of the active layer were quantitatively analyzed. The results demonstrate that rainfall changes significantly affect the Bowen ratio, which in turn affects surface energy exchange. Under wet/dry conditions, there is a positive correlation between rainfall and liquid water flux under the hydraulic gradient; water vapour migration is the main form under the temperature gradient, which indicates that the influence of water vapour migration on thermalmoisture dynamics of the active layer cannot be neglected. Concurrently, regardless of wet or dry conditions, disturbance of the heat transport by conduction caused by rainfall is stronger than that of convection by liquid water. In addition, when rainfall decreases by 1.5 times (212 mm) and increases by 1.5 times (477 mm), the thickness of the active layer increases by 0.12 m and decreases by 0.21 m, respectively. The results show that dry conditions are not conducive to the preservation of frozen soil; however, wet conditions are conducive to the preservation of frozen soil, although there is a threshold value. When this threshold value is exceeded, rainfall is unfavourable for the development of frozen soil.

期刊论文 2023-02-01 DOI: 10.1016/j.rcar.2023.04.002 ISSN: 2097-1583
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