Expansive clay soil is known to cause damage to pavements due to its volume fluctuations with changes in moisture content, a phenomenon observed globally in many countries. Implementing suitable stabilisation treatments is crucial for improving the mechanical and hydraulic properties of the expansive clay subgrade. While cement and lime have traditionally been widely used as soil stabilisers, there is a growing emphasis on sustainable engineering due to increased awareness of global warming. Seeking alternative green and sustainable materials for soil stabilisation is demanded now, and one such alternative is using ethylene-vinyl acetate (EVA) copolymer emulsion. However, the use of EVA copolymer emulsion for stabilising expansive clay has been relatively underexplored in existing studies. This study evaluates the feasibility of utilising EVA copolymer emulsion for stabilising expansive clay subgrade through comprehensive laboratory tests to assess the mechanical (compaction, unconfined compressive strength, California bearing ratio, resilient modulus, and direct shear), hydraulic (soil-water retention curve and swellshrinkage), and micro-chemical (thermogravimetric analyses and scanning electron microscopic) performance of the soil. The experimental results indicate that the inclusion of 1 % EVA copolymer emulsion into the expansive clay provided the highest mechanical properties, resulting in an increase in the unconfined compressive strength, soaked California bearing ratio, resilient modulus, and cohesion by 8.8 %, 177.8 %, 35.8 % and 19.4 %, respectively. Swell-shrinkage behaviour was also improved with the addition of EVA copolymer, with 1 % EVA copolymer presenting the lowest swell-shrinkage index of 3.19 %/pF (14 % decrease in shrink-swell potential compared to the untreated clay).

Bio-active packaging films from cellulose acetate incorporated with cypress essential oil (Cyp) have been developed. Thus, cellulose acetate (CA), which is a biodegradable and renewable polymer has been used as an alternative to petroleum-based polymers. Cellulose acetate films were prepared via a solvent casting method incorporating 0, 10, 30, and 60% (w/w) of Cyp. The purpose was to evaluate the possible changes caused by the Cyp on the properties of the packaging films. Different methods and technics have been used to characterize these films. The antibacterial and antioxidant properties of the films were also analyzed. FTIR and XRD analysis indicated that Cyp was homogenously distributed in the films. Meanwhile, TGA analysis demonstrated that the addition of Cyp had an impact on thermal-oxidative properties of the films. The CA/Cyp films showed excellent biodegradability in soil after 60 days, with a percentage loss of 87.07% by mass, and improved mechanical properties with tensile strength and elongation-at-break of 8.1 +/- 0.2 MPa and 16.6 +/- 0.2%, respectively. Water absorption and water solubility values for CA/Cyp films ranged from 76.62 +/- 0.91% to 21.95 +/- 0.57% and from 1.29 +/- 0.35 to undetectable levels, respectively. The results displayed that antibacterial activity against Escherichia coli and Staphylococcus aureus increased as the percentage of Cyp increased in the cellulose acetate films. Moreover, the free radical scavenging activity of cellulose acetate films was improved by increasing the Cyp concentration. These results indicate that cellulose acetate films containing a low-cost essential oil like Cyp have potential for use as active packaging for foods.

Currently, utilization of hydrophilic polyurethane (W-OH) materials for slope protection in arid areas has proved to be a cost-effective protocol. The treatment effect highly depends on the interfacial performance between the W-OH treated and the original sandstone. This study aims to investigate the corresponding shear strength and its long-term performance under dry-wet cycles under the arid environment. The results from the direct shear test indicate the interface shear strength increases with W-OH solution concentration and decreases with the increase of water content of the Pisha sandstone. Further investigations under dry-wet cycles indicate the interface cohesion is obviously weakened by the dry-wet cycles, while the influence on the internal friction angle is not obvious. The correlation between the degradation level and the dry-wet cycles can be well fitted with the inverted Scurve using two combined exponential functions. Furthermore, the ethylene-vinyl acetate (EVA) content is utilized to enhance the durability performance under dry-wet cycles. It is found the EVA can obviously improve the bonding property and the resistance to dry-wet cycles. This study's results can serve as a solid base for the application of W-OH materials to resolve the soil erosion in the arid region.

The objective of this study was to produce new active and intelligent high performance colorimetric films based on cellulose acetate (CA), and to evaluate the synergistic effect of thymol (THY) and anthocyanin (ANT). The colour films showed significant reactivity to pH change, and the films became thicker in the presence of glycerol (0.200 +/- 0.05). FTIR and SEM images showed a homogeneous distribution and new interactions created between THY, ANT and CA, which modified the thermal properties. This behaviour was also confirmed by XRD analysis, which showed a reduction in film crystallinity with increasing anthocyanin concentration. In addition, the incorporation of ANT improved the mechanical properties by reducing the tensile strength (0.075 +/- 0.021 MPa), the biodegradability of the films in the soil after 60 days and also the water vapor transmission rate (14.81 g mm-2 h-1). The films showed synergistic antibacterial activity and the application trials showed colour changes that were highly visible to the naked eye, with the deterioration of the fish, suggesting a promising application for these films as an indicator of fish freshness.

This work studied biocomposites based on a blend of low-density polyethylene (LDPE) and the ethylene-vinyl acetate copolymer (EVA), filled with 30 wt.% of cellulosic components (microcrystalline cellulose or wood flour). The LDPE/EVA ratio varied from 0 to 100%. It was shown that the addition of EVA to LDPE increased the elasticity of biocomposites. The elongation at break for filled biocomposites increased from 9% to 317% for microcrystalline cellulose and from 9% to 120% for wood flour (with an increase in the EVA content in the matrix from 0 to 50%). The biodegradability of biocomposites was assessed both in laboratory conditions and in open landfill conditions. The EVA content in the matrix also affects the rate of the biodegradation of biocomposites, with an increase in the proportion of the copolymer in the polymer matrix corresponding to increased rates of biodegradation. Biodegradation was confirmed gravimetrically by weight loss, an X-ray diffraction analysis, and the change in color of the samples after exposition in soil media. The prepared biocomposites have a high potential for implementation due to the optimal combination of consumer properties.

Effective enhancement of the mechanical properties of cohesionless soils is crucial for diverse geotechnical applications, given their inherent vulnerability to load-induced failure due to the absence of inter-particle bonding. Soil failures pose significant risks to both human lives and infrastructure, necessitating the development of environmentally friendly soil improvement methods. Conventional techniques often entail invasive processes and substantial carbon emissions. In response, contemporary approaches seek to minimize environmental impact while preserving organic material characteristics. This study investigates the synergistic effect of polyvinyl acetate (PVA) and enzyme-induced carbonate precipitation (EICP) treatment for enhancing the mechanical properties of cohesionless natural sands. Beach and river sands were treated with varying proportions of PVA in conjunction with an optimized EICP solution for yielding the best results. Unconfined compressive strength (UCS) tests were conducted at 7, 14, and 28 -day curing intervals to assess the performance of the soil-polymer-EICP composites (SPEC). The results demonstrated substantial improvements in compressive strength and elastic modulus with increasing PVA content. For beach sand, after 7 days of heat curing, the peak strength increased from 0.89 MPa to 11.07 MPa for composites with 1% and 11% PVA, respectively. Similarly, for river sand, the peak strength increased from 0.87 MPa to 8.96 MPa under the same conditions. The findings also highlighted the softening behavior induced by PVA with heat curing over the period. This softening phenomenon was attributed to the thermo-plastic characteristics of the polymer film induced by temperature conditions.

The fate of permafrost carbon upon thaw will drive feedbacks to climate warming. Here we consider the character and context of dissolved organic carbon (DOC) in yedoma permafrost cores from up to 20m depth in central Alaska. We observed high DOC concentrations (4 to 129mM) and consistent low molecular weight organic acid concentrations in three cores. We estimate a DOC production rate of 12 mu molDOCm(-2)yr(-1) based on model ages of up to similar to 200kyr derived from uranium isotopes. Acetate C accounted for 241% of DOC in all samples. This proportion suggests long-term anaerobiosis and is likely to influence thaw outcomes due to biolability of acetate upon release in many environments. The combination of uranium isotopes, ammonium concentrations, and calcium concentrations explained 86% of the variation in thaw water DOC concentrations, suggesting that DOC production may be related to both reducing conditions and mineral dissolution over time.