The widespread distribution of saline soil in the severe cold regions of northwest China has caused dual damage to concrete structures, including freeze-thaw cycles and sulfate erosion, seriously threatening the adhesive performance of interface agents. To solve the problem, the evolution law of the interface adhesive performance of the interface agent in standard curing, natural exposure, freeze-thaw cycle and sulfate attack environment was studied by modified acrylate lotion. The results indicated that environmental factors have a significant impact on interface strength, with the destructive effect of freeze-thaw cycles being the most prominent. The modified acrylate lotion improved the interface performance through a triple action mechanism: (1) penetrated the matrix to form a pore bolt structure, enhancing the mechanical anchoring effect; (2) The complexation of carboxylic acid carbonyl groups with Ca2+ enhanced the chemical adhesive strength; (3) Its flexibility and filling effect reduced freezing pressure, refined pores, and effectively inhibited water migration and ion erosion. The study further revealed the key mechanisms of interface pore coarsening, and pore plug structure degradation in freezethaw environments, providing new solutions and theoretical support for concrete repair in cold regions.

The present study examines the mechanical and morphological characteristics of a green composite reinforced with pineapple leaf fiber (PLF) under different environmental conditions. PLF underwent chemical treatment at optimal conditions, using a 1% w/v sodium carbonate solution for 6 hours, to produce an environmentally friendly pineapple leaf fiber (PLF)/polylactic acid (PLA)-based composite via injection molding. The optimal injection settings of 165 degree celsius (melting temperature), 50 mm/sec (injection speed), and 110 bars (injection pressure) to produce the PLF/PLA composite. The PLF/PLA composite was developed with a fiber loading of 20% and a length of 3 mm. The produced PLF/PLA composites were then exposed to a variety of environmental conditions, including water, soil, refrigeration, and room temperature. The impact of these diverse conditions on the mechanical properties (tensile, flexural, compression, and shear) was scientifically observed for four -week. Additionally, the morphology of the fractured specimens was assessed using a scanning electron microscope (SEM). The contact angle measurement was conducted to assess the hydrophilic characteristics of the PLF/PLA green composite. There has been a lack of comprehensive research on the effects of different environmental conditions on the mechanical, wettability, and morphological properties of green composites derived from PLF/PLA. Thus, in this study, emphasis is given for investigating the effect of various environmental conditions on the mechanical properties of PLF/PLA injection -molded green composite. The composite material demonstrated the highest water absorption and swelling thickness at 6.45% and 5.51%, respectively, in comparison to the dry PLF/ PLA samples. The green composite of PLF/PLA demonstrated excellent mechanical performance under ambient conditions compared to other environmental conditions. The PLF/PLA composite displayed a peak contact angle of 83.26 degrees when subjected to soil burial conditions. On the contrary, the initial samples of the PLF/PLA composite displayed the minimum contact angle of 56.72 degrees .

The present investigation evaluates the mechanical, thermal, morphological, and crystalline behaviour of green composite reinforced with bamboo fibre under recycling and various environmental conditions. The short bamboo fibre was chemically modified at an optimum condition by treating the fibre for 4 h using sodium hydroxide (2% w/v) to produce a sustainable bamboo fibre (BF)/polylactic acid (PLA) composite through injection moulding. The optimum injection conditions considered to develop BF/PLA composite were a melting temperature of 165 degrees C, injection speed of 60 mm/s, and injection pressure of 90 bars. The fibre length and loading of 4 mm and 20% were considered to fabricate the BF/PLA green composite. The developed BF/PLA composites were exposed to different environmental conditions like water, soil, refrigerator, and room temperature for four weeks. The fabricated BF/PLA green composite specimens were recycled five times by implementing the manual mechanical cutting process. The impact of various environmental conditions and recycling on the mechanical properties was systematically monitored. The morphology of the fractured recycled specimens and specimens exposed to different environmental conditions were also examined using a scanning electron microscope (SEM). The thermo gravimetric analysis (TGA) was performed on the recycled BF/PLA specimens to investigate the thermal degradation behaviour of the developed composites. The crystalline behaviour of the BF/PLA composite exposed to different environmental conditions and recycled samples was also analysed by using X-ray diffraction (XRD). The maximum water absorption and thickness of swelling of the developed composite were observed at 6.49% and 5.56% when compared to the dry BF/PLA specimens. The mechanical behaviour of the BF/PLA green composite was superior in room temperature conditions followed by refrigerating, soil burial, and water immersion conditions. The maximum degradation temperature of non-recycled and after the fifth recycled BF/PLA composite was perceived at 348 degrees C and 329 degrees C. The deterioration in PLA and BF was observed due to the thermo-mechanical recycling. The degree of crystallinity of the unexposed sample was observed as 57.75% with a semi-crystalline nature. The crystallinity of BF/PLA composite was changed to amorphous while exposed to water, soil, refrigerator, and room temperature with a degree of crystallinity of 9.41%, 18.62%, 31.62% and 37.93%. Meanwhile, the fifth recycled BF/PLA composite exhibited a degree of crystallinity of 12.71%.

The forest plantations (Norway spruce, pine) installed outside the habitat are fragile, vulnerable ecosystems, exposed to some risk factors, registering significant damages. In the paper, the analysis of the environmental conditions of some lands with Norway spruce stands outside the habitat, affected by intense drying, and the substantiation of their ecological restoration solutions are presented. The results were obtained based on research carried out in 2023 in the area of the Suceava Plateau (Marginea Forest District). The physicochemical characteristics of the soils were strongly altered, having a low content of nutrients and minerals, with a contrasting texture, being poor in bases and heavy drainage, strong acidity, and affected by pseudo-glazing processes. The ecological restoration of Norway spruce stands affected by drying consists of replacing them with species corresponding to the environmental conditions, but only after carrying out special land and soil preparation works to improve its physical and chemical properties. The results obtained are particularly important considering the need for ecological restoration of large areas with Norway spruce stands outside the habitat, strongly affected by drying.

Aim Litter humification is vital for carbon sequestration in terrestrial ecosystems. Probing the litter humification of treeline ecotone will be helpful to understand soil carbon afflux in alpine regions under climate change. Methods Foliar litter of six plant functional groups was chosen in an alpine treeline ecotone of the eastern Tibetan Plateau, and a field litterbag decomposition experiment (669 days) was conducted in an alpine shrubland (AS) and a coniferous forest (CF). Environmental factors, litter quality, humus concentrations (total humus, Huc; humic acid, HAc; and fulvic acid, FAc) and hue coefficient (Delta logK and E4/E6) were measured to explore litter humification processes. Results Litter humification was controlled by both litter stoichiometric traits and local-environment conditions, while stoichiometric traits played a more obvious regulatory role. Significant discrepancies in litter humus were detected among six plant functional groups; more precisely, litter of evergreen conifer and shrubs showed a net accumulation of Huc and FAc during winter, whereas others experienced more mineralization than accumulation. Huc, HAc, and hue coefficient were mainly controlled by cellulose/N, cellulose/P, C/N, lignin/P, lignin/N, etc., yet FAc was more susceptible to local-environment conditions. Meanwhile, Huc, HAc and FAc, as well as humification degree and E4/E6 differed between AS and CF, with faster humification in AS. Conclusion We suggest that litter stoichiometric traits are more responsible for regulating litter humification than environmental conditions in elevational gradients. Furthermore, potential upward shifts by plants may accelerate litter humification in alpine ecosystems.

During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to better prepare societies for future developments. A key principle of NEFI is that these developments must now be secured through science-based strategies co-designed with regional decision-makers to lead their societies to prosperity in the face of environmental and institutional challenges. NEESPI scientific research, data, and models have created a solid knowledge base to support the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge. It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFI science questions. To address these questions, nine research foci are identified and their selections are briefly justified. These foci include warming of the Arctic; changing frequency, pattern, and intensity of extreme and inclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes in the biosphere; pressures on land use; changes in infrastructure; societal actions in response to environmental change; and quantification of Northern Eurasia's role in the global Earth system. Powerful feedbacks between the Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphere essential for water supply, retreat of sea ice) result from past and current human activities (e.g., large-scale water withdrawals, land use, and governance change) and potentially restrict or provide new opportunities for future human activities. Therefore, we propose that integrated assessment models are needed as the final stage of global change assessment. The overarching goal of this NEFI modeling effort will enable evaluation of economic decisions in response to changing environmental conditions and justification of mitigation and adaptation efforts.