This study investigates the influence of wood pellet fly ash blended binder (WABB) on the mechanical properties of typical weathered granite soils (WS) under a field and laboratory tests. WABB, composed of 50 % wood pellet fly ash (WA), 30 % ground granulated blast furnace slag (GGBS), and 20% cement by dry mass, was applied at dosages of 200-400 kg/m3 to four soil columns were constructed at a field site deposited with WS. After 28 days, field tests, including coring, standard penetration tests (SPT), and permeability tests, revealed enhanced soil cementation and reduced permeability, indicating a denser soil matrix. Unconfined compressive tests (UCT) and free-free resonant column (FFRC) tests on field cores at 28 and 56 days, compared with laboratory specimens and previously published data, demonstrated strength gains 1.2-2.1 times higher due to field-induced stress. The presence of clay minerals influenced the WABB's interaction and microstructure development. Correlations between seismic waves, small-strain moduli, and strength were developed to monitor in-situ static and dynamic stiffness gain of WABB-stabilized weathered granite soils.

Permafrost is one of the crucial components of the cryosphere, covering about 25% of the global continental area. The active layer thickness (ALT), as the main site for heat and water exchange between permafrost and the external atmosphere, its changes significantly impact the carbon cycle, hydrological processes, ecosystems, and the safety of engineering structures in cold regions. This study constructs a Stefan CatBoost-ET (SCE) model through machine learning and Blending integration, leveraging multi-source remote sensing data, the Stefan equation, and measured ALT data to focus on the ALT in the Qinghai-Tibet Plateau (QTP). Additionally, the SCE model was verified via ten-fold cross-validation (MAE: 20.713 cm, RMSE: 32.680 cm, R2: 0.873, and MAPE: 0.104), and its inversion of QTP's ALT data from 1958 to 2022 revealed 1998 as a key turning point with a slow growth rate of 0.25 cm/a before 1998 and a significantly increased rate of 1.26 cm/a afterward. Finally, based on multiple model input factor analysis methods (SHAP, Pearson correlation, and Random Forest Importance), the study analyzed the ranking of key factors influencing ALT changes. Meanwhile, the importance of Stefan equation results in SCE model is verified. The research results of this paper have positive implications for eco-hydrology in the QTP region, and also provide valuable references for simulating the ALT of permafrost.

The cement-stabilization technique is employed on natural and recycled granular materials to improve their mechanical properties. The strength of these materials is assessed by the unconfined compressive strength on laboratory compacted specimens, typically after 7 days of curing. Standards and technical specifications specify different values of specimen height and diameter and different loading modes of testing. This makes the comparison between different materials and with the acceptance limits of technical specifications difficult. The research investigates the effect of specimen size and loading mode on the unconfined compressive strength of both natural and recycled cement-stabilized granular materials. The results revealed significant differences in strength due to variations in specimen size and loading mode. As expected, an increase in specimen slenderness resulted in a decrease in compressive strength. A linear regression model was developed to quantify the effect of the experimental variables on the compressive strength of the two cement-stabilized materials.

Sustainable polymers have attracted interest due to their ability to biodegrade under specific conditions in soil, compost, and the marine environment; however, they have comparatively lower mechanical properties, limiting their widespread use. This study explores the effect of incorporating waste soy biomass into sustainable polymers (including biodegradable and biobased) on the thermal and mechanical properties of the resultant blends. The dispersion of the waste soy biomass in the polymer matrix is also investigated in relation to particle size (17 mu m vs. 1000 mu m). Fine waste soy biomass did not significantly affect the melting temperature of the polymers (polyhydroxyalkanoates, polybutylene adipate terephthalate, polybutylene adipate terephthalate/poly(lactic) acid, and biobased linear low-density polyethylene) used in this study, but their enthalpy of fusion decreased after soy was melt-blended with the polymers. The tensile modulus of the polymers filled with fine waste soy biomass powder (17 mu m) was enhanced when melt-blended as compared to unfilled polymers. Additionally, it was found that fine waste soy powder (17 mu m) increased the tensile modulus of the polymer blends without significantly affecting processability, while coarse waste soy meal (1000 mu m) generally reduced elongation at break due to poor dispersion and stress concentration; however, this effect was less pronounced in PHA blends, where improved compatibility was observed.

Salvia splendens Ker-Gawl. (scarlet sage), widely used in urban landscaping, it is frequently exposed to cadmium (Cd) contamination resulting from industrial and vehicular emissions. However, its tolerance and adaptability to Cd stress remain poorly understood. A soil experiment was conducted to investigate the effects of Cd on the growth and the photosynthetic performance of S. splendens by measuring photosynthetic pigments, gas exchange and chlorophyll fluorescence parameters. Four weeks-seedlings were treated with 0 (CK), 0.5, 2.5, 5, 10, 25 and 50 mgkg(-1) Cd for 60 days. Results showed significant reductions in root length and biomass of leaves, stems, and roots, with shoot and root biomass notably decreasing by up to 46.3% and 28.5% at higher Cd levels, respectively. The translocation factor remained low (TF 5 mgkg(-1)) caused a decrease in Chl a and Chl b content, but increased the Chl a/b ratio, thereby disrupting photosynthesis and causing significant declines in photosynthetic parameters. Cd exposure (> 2.5 mgkg(-1)) significantly decreased net photosynthetic rate (Pn) by 18.94-52.91%, stomatal conductance (Gs) by 35.77-58.53%, and transpiration rate (Tr) by 24.63-48.83%, accompanied by only a slight reduction in inter-cellular CO2 concentration (Ci) of just 7.0%, indicating non-stomatal factors in Pn decline. Cd concentrations (> 5 mgkg(-1)) caused a reduction in initial fluorescence (Fo) by 7.44-31.58% and maximal fluorescence (Fm) measurements by about 20%, indicating damage to photosystem II (PSII). At 50 mgkg(-1), further decreases were observed in photochemical quenching (qP) by 40.31%, the quantum yield of photochemical energy dissipation (Phi PSII) by 44.77%, and the electron transport rate (ETR) by 25.11%, while non-photochemical quenching increased by 42.66%, signifying significant PSII inhibition and enhanced photoinhibition. Decrease in Phi PSII, along with the increase in the quantum yield of regulated non-photochemical energy loss in PSII (Phi NPQ) and the quantum yield of non-regulated energy loss in PSII (Phi NO) as Cd levels rise, indicates enhanced non-photochemical energy dissipation and greater photoinhibition. S. splendens shows high sensitivity to Cd stress, with reduced growth and disrupted photosynthesis, highlighting its potential as a bioindicator for Cd contamination in urban areas.

PurposeThe present work aims to prepare biocomposites blend based on linear low density polyethylene/ starch without using harmful chemicals to improve the adhesion between two phases. Also, the efficiency of essential oils as green plasticizers and natural antimicrobial agents were evaluated.Design/methodology/approachBarrier properties and biodegradation behavior of linear low density polyethylene/starch (LLDPE/starch) blends plasticized with different essential oils including moringa oleifera and castor oils wereassessed as a comparison with traditional plasticizer such as glycerol. Biodegradation behavior forLLDPE/starch blends was monitored by soil burial test. The composted samples were recovered then washed followed by drying, and weighting samples after 30, 60, and 90 days to assess the change in weight loss. Also, mechanical properties including retention values of tensile strength and elongation at break were measured before and after composting. Furthermore, scanning electron microscope (SEM) was used to evaluate the change in the morphology of the polymeric blends. In addition to, the antimicrobial activity of plasticized LLDPE/starch blends films was evaluated using a standard plate counting technique.FindingsThe results illustrate that the water vapor transition rate increases from 2.5 g m-2 24 h-1 for LLDPE/5starch to 4.21 g m-2 24 h-1 and 4.43 g m-2 24 h-1 for castor and moringa oleifera respectively. Also, the retained tensile strength values of all blends decrease gradually with increasing composting period. Unplasticized LLDPE/5starch showed highest tensile strength retention of 91.6% compared to the other blends that were 89.61, 88.49 and 86.91 for the plasticized LLDPE/5starch with glycerol, castor and M. oleifera oils respectively. As well as, the presence of essential oils in LLDPE/ starch blends increase the inhibition growth of escherichia coli, candida albicans and staphylococcus aureus.Originality/valueThe objective of this work is to develop cost-effective and environmentally-friendly methods for preparing biodegradable polymers suitable for packaging applications.

The rapid growth of construction activities in India has led to a significant increase in the generation of construction and demolition waste (CDW). This waste poses a major environmental and economic challenge. One sustainable method to manage construction and demolition waste is to reuse the aggregates that are collected after the demolition of structures and damaged roads. In this study, a design mix of granular sub base (GSB) layer of close graded-grading II was considered. The GSB layer is a layer of compacted aggregate that is placed below the road surface to provide a stable base for the pavement. The design mix consisted of 40, 20, and 10 mm natural aggregates (NA), 20 mm of recycled aggregates (RA) collected from demolished buildings/concrete waste/damaged roads, and blended soil (BS). The properties of the clay with intermediate plasticity soil were enhanced with the addition of crusher dust for the preparation of BS. The RA were used to replace the NA in the design mix. The best combination of aggregates that met the specifications of the Ministry of Road Transport and Highways was selected. The results showed that up to 60% of the 20 mm natural aggregates could be replaced with recycled aggregates without compromising the performance of the GSB layer. The maximum dry density and optimum moisture content after replacement were found to be 2.00 g/cm3 and 10.37%, respectively. The California Bearing Ratio value at 2.5 mm penetration was also found to be 38.47. These results suggest that RA can be used as a sustainable alternative to NA in the construction of GSB layers. This can help to reduce the environmental issues of CDW and save natural resources.

Concrete surfaces in the evaporation zone above sulfate-rich soils are subject to severe damage from scaling. Such a physical sulfate attack (PSA) on concrete is a consequence of a cyclic regime between hot-dry and cold-wet environments, during which sodium sulfate crystals expand within the porous media (binder matrix or aggregate) and exert high pressure on the pore walls. Currently, no accepted standard exists for evaluating the resistance of concrete to the PSA phenomenon. In this study, an accelerated physical sulfate attack test protocol was used to determine the effect of blended cement and water-to-binder ratio on concrete resistance to PSA. The testing included a preconditioning protocol for presaturating concrete specimens in a 10% sodium sulfate solution for 15 days, with heat-drying specimens at 50 degrees C before and after immersion. Specimens were then partially immersed in a 10% sodium sulfate solution and subjected to a cyclic regime composed of hot-dry [40 degrees C, 30% RH] and cold-wet [8 degrees C, 85% RH] conditions for 19 h each, separated by a 4-h transition at room temperature. Silica fume (GUb-SF), limestone (GUL), and slag (GUb-S) blended cements were used and compared with general use (GU) cement. A fifth binder (GUL-GP) contained 20% glass powder as a partial replacement of the limestone-portland cement was also used. Three different water-to-binder ratios were used for each binder: 0.35, 0.45, and 0.55. As expected, mixes with lower water-to-binder ratios showed the best performance against PSA, i.e., the lowest mass loss after 15 cycles of exposure (30 days). GUb-SF cement improved the resistance of mixtures with a high water-to-binder ratio compared to GU mixtures. Contrary to silica fume and slag, limestone reduced the resistance of concrete to PSA and showed the highest rate of visual damage for all water-to-binder ratios.

In this study, the Pseudomonas fluorescens-based lipase enzyme was utilized to enhance the comfort and hydrophilic properties of polyester/cotton blend fabric. The experiment was set up, the major influencing elements were examined, and the appropriate operational parameter levels were established using the Box-Behnken design approach. To express the wettability and moisture regain of treated fabrics, temperatures, lipase enzyme concentrations, and treatment time were taken as independent variables. The ideal optimum lipase enzyme treatment parameters were found to be 30 degrees C temperature, 14% lipase concentration, and 50 min of treatment time. At optimal operating conditions, the moisture regain and wettability for lipase-treated p/c blend fabrics enhanced to 1.8 +/- 0.02% and 6.3 cm capillary rise(2-s drop test and 2-s sinking time), respectively. The lipase enzyme-treated p/c blend fabrics are characterized by a totally reduced susceptibility to fabric pilling which is 4-5 as well as a restricted ability to combine oily impurities and a high oil-soil-release capability of stain removal index of 95% and also showed a surface resistivity decreased by one order of magnitude under normal conditions which is 470 s of half-life decay time. Generally, the effects of the lipase enzyme treatment on the fabric properties were then assessed by FT-IR, TGA, DSC, moisture regain, tensile strength, stain repellency, pilling resistance and anti-static charge generation.

Biochar (BC) is an eco-friendly material produced through coal pyrolysis and can improve the mechanical properties of cement-based construction and building materials. This research study explored the effects of BC and natural sand (Sand) replacement on the improved static and cyclic response of blended hydraulic cement (BHC) stabilized soft clay (SC) as a greener subgrade material. Unconfined compressive strength (UCS), indirect tensile stress (ITS), and indirect tensile fatigue life (ITFL) of the BHC-stabilized SC-BC-Sand samples were examined. Adding 10% BC to the BHC-stabilized samples was found to enhance cementitious products due to its porous structure and high water absorbability. The UCS, ITS and ITFL at this optimum ingredient were improved up to 315%, 347% and 862%, respectively, compared to the BHC-stabilized SC. Fourier transform infrared spectrometer, thermogravimetry differential thermal analysis and a scanning electron microscope with energy- dispersive-ray spectroscopy analyses the BHC-stabilized sample at the optimum ingredient showed the highest C-S-H and Ca(OH)2 2 in the pores. This investigation will encourage the utilization of BC to create both environmentally friendly and durable stabilized subgrade material.