Abstract

AISI 304 austenitic stainless steel (ASS) was systematically investigated to evaluate its mechanical behavior at cryogenic temperatures, with particular emphasis on its potential application in cryo-compressed hydrogen storage systems. Such systems are considered a cornerstone technology in the realization of global clean energy and decarbonization targets for 2050. To assess AISI 304 ASS's performance under cryogenic conditions, uniaxial tensile tests were conducted at room temperature (298 K) and at progressively reduced temperatures of −30 °C (243 K), −60 °C (213 K), and −80 °C (193 K). All experiments were performed using a universal testing machine equipped with a cooling chamber under a constant strain rate of 10⁻³ s⁻¹ to ensure the consistency and reliability of results. The experimental data revealed a distinct temperature-dependent strengthening response. The ultimate tensile strength (UTS) increased significantly by approximately 54.2% as the testing temperature decreased, while the yield strength demonstrated a more moderate improvement of 7.25%. Although uniform elongation showed a gradual reduction with decreasing temperature, the alloy retained sufficient ductility, thereby maintaining a favourable strength–ductility balance even under cryogenic conditions. These results confirm that AISI 304 ASS possesses the mechanical reliability necessary for hydrogen storage at low temperatures. Beyond its demonstrated mechanical suitability, the deployment of this widely available material supports broader sustainability objectives. Its use in cryo-compressed hydrogen storage can directly contribute to strengthening clean energy infrastructure, minimizing carbon emissions, reducing health risks associated with fossil fuel reliance, and accelerating the global transition toward a net-zero energy system by 2050.

The progressive miniaturization of electronic and photonic devices has catalyzed growing scientific interest in the structural and functional behavior of ultrathin liquid crystal (LC) films. In this study, we present the first successful fabrication of ultrathin films of 4-hexyl-4’-isothiocyanatobiphenyl (6BT), a non-glassforming liquid crystal, using organic molecular beam deposition (OMBD) under room temperature conditions. This solvent-free, vacuum-based deposition technique enables precise control over film growth and molecular organization at the nanoscale.

Quantitative thickness measurements were performed using spectroscopic ellipsometry and X-ray reflectometry, allowing nanometer-resolution characterization of film morphology. Fourier-transform infrared (FTIR) spectroscopy revealed a distinct evolution of molecular ordering with increasing film thickness. At minimal thicknesses, we observe initial self-organization dominated by π–π stacking of aromatic biphenyl cores and van der Waals interactions among alkyl chains. As the film grows thicker, a significant degree of orientational ordering emerges among the isothiocyanate (-NCS) terminal groups, suggesting enhanced intermolecular cooperativity.

Complementary broadband dielectric spectroscopy (BDS) was employed to probe the dynamic response of the films, uncovering relaxation processes and vibrational dynamics that progressively shift toward bulk-like behavior with increasing thickness. These findings provide fundamental insight into structure–property relationships in confined liquid crystalline systems.

Our results offer a new platform for tailoring liquid crystal alignment, dynamics, and interfacial interactions in ultrathin geometries, opening promising avenues for the integration of anisotropic organic materials into next-generation nanoelectronic, photonic, and sensing technologies.

Worldwide, the sunflower is an important agricultural crop—the seeds are used as a food source for people and animals, and as feedstock for liquid biofuel production. The biomass residues are utilised as solid biofuel for local heating systems and industrial facilities. Although the biomass ash is a tertiary product of biomass usage, it is not classed as waste—depending on the biomass type, it consists of valuable elements such as potassium, calcium, sodium, phosphorus, etc. The current study aims to investigate the alkalizing properties of biomass ash in two forms: sunflower husk ash (SHA) and sunflower husk ash granules (SHAGs). Both materials were characterized with dominant alkaline oxides, as K₂O was in the range of 15.09-17.56 wt. % and Na₂O was in the range of 4.42-6.19 wt. %. The pH measurements were carried out with an apparatus type HI-5522, while the elemental analysis of solid and liquid samples was performed using an X-ray fluorescence (XRF) apparatus type E-lite. The experiments were conducted with 30 ml of deionized water, different amounts (2 and 3 g) of SHA and SHAG, with and without stirring, at contact times of 2 and 72 hours. The investigated materials demonstrated good alkalizing properties—the pH rose from 6.8 to over 10.3 and remained stable over time, with a maximum pH of 10.96 for 3 g SHA without stirring, after 2 hours. The XRF results were similar for both materials—Na reacted with water was found to contain 37.51% SHA and 35.87% SHAG, while the dissolved K in the water was measured at 84.43% for SHA and 83.33% for SHAG. The obtained results are a prerequisite for further utilization of this by-product as a green chemical material for increasing pH, with different applications like the production of liquid fertilizers, soaps, etc., or for wastewater decontamination from heavy metals.

Lignin is an essential yet underutilized component in biomass valorization. A majority of molecular dynamics (MD) studies on lignocellulosic dissolution via DESs use choline chloride as a hydrogen bond acceptor (HBA). In contrast, this study adopts a lignin-first approach, employing tetraethylammonium chloride (TEAC) as the HBA, to better understand how alternative DES formulations modify lignin–cellulose interactions and propose avenues for selective lignin dissolution. All-atom MD simulations were performed on a representative lignin–cellulose complex solvated in two binary DES systems: TEAC:urea (1:2) and TEAC:lactic acid (1:2). Each system underwent energy minimization, equilibration, and 300 ns production runs at 373.15 K and 1 bar using the CHARMM36 force field. Analyses included RMSD, solvent-accessible surface area (SASA), hydrogen bonding, radial distribution function, and interaction energies, with emphasis on lignin responses. Results showed that cellulose remained structurally robust in both solvents. Lignin, however, displayed marked solvent-dependent differences in stability. In the TEAC:urea system, lignin maintained a comparatively stable conformation, with hydrogen bonding largely preserved and solvent interactions being less disruptive. In contrast, lignin was noticeably more unstable in TEAC:lactic acid, where solvent penetration was stronger, hydrogen bonds were disrupted more extensively, and DES–lignin interactions proved more destabilizing. These contrasting behaviors underline the importance of solvent environment in driving lignin conformational changes. By prioritizing lignin behavior and employing TEAC as an alternative HBA, this study highlights solvent-specific mechanisms for lignin dissolution, offering molecular-level guidance for lignin-first biomass processing and broadening the design space for green DES formulations beyond choline chloride.

Abstract

Introduction:
Copper nanoparticles (CuNPs) have attracted significant interest due to their diverse applications, particularly in antimicrobial treatments. In agriculture, the bacterial pathogen Burkholderia glumae (BG) is recognized as the primary causal agent of bacterial panicle blight (BPB) in rice, a disease that severely reduces yield and grain quality. Current management strategies, including chemical treatments, cultural practices, and resistant cultivars, remain limited by resistance development, inconsistent field performance, and environmental concerns. Therefore, the development of eco-friendly and effective alternatives is urgently needed.

Methods:
In this study, CuNPs were synthesized through a green mycosynthesis approach using Pleurotus ostreatus (oyster mushroom) extract, with the synthesis process enhanced via an autoclave-assisted method. The nanoparticles were characterized by UV–Vis spectroscopy, field emission scanning electron microscopy (FESEM), and Fourier-transform infrared spectroscopy (FTIR). Antibacterial activity was evaluated against six BG strains of varying pathogenicity through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays.

Results:
Characterization confirmed successful nanoparticle formation, with a distinct absorption peak at 374 nm. FESEM images revealed irregular morphologies and a wide size distribution ranging from 41.56 to 131.9 nm, while FTIR spectra indicated functional groups acting as capping and stabilizing agents. Antibacterial testing demonstrated that the synthesized CuNPs were effective against all BG strains, with the lowest bactericidal concentration observed at 2.5 mg/mL.

Conclusion:
These findings highlight the potential of autoclave-assisted mycosynthesized CuNPs as an environmentally sustainable and efficient alternative for the control of B. glumae. Their dual ability to suppress bacterial growth and provide eco-friendly synthesis suggests a promising application in rice disease management and sustainable agriculture.

Rapid‐setting concretes are commonly used for pavement repairs due to their high early‐age strength and ability to expedite traffic resumption. However, the accelerated hydration that drives rapid strength gain can alter microstructural development, creating potential trade‐offs between early performance and long‐term durability. This study evaluates calcium sulfoaluminate (CSA), polymer‐modified, and prepackaged rapid‐strength systems under three curing regimes (10 °C, ambient temperature, and 35 °C). The internal temperature evolution was monitored in laboratory specimens using a temperature logger and a controlled environmental chamber for 24 h, and compressive strength was measured at multiple ages up to 28 days per ASTM standard. The results show that elevated curing temperatures (35 °C) accelerated hydration, achieving 20–25 MPa within 4 h, but reduced 28‐day strength by up to 15 % compared with ambient curing. Low‐temperature curing delayed strength development but increased 28‐day strength by 8–12 %. Several mixtures exhibited bimodal thermal profiles—an initial exotherm within 2 h followed by a secondary peak at 6–8 h—suggesting complex ettringite formation and secondary hydration reactions. These behaviors are crucial for understanding the compactibility of repair materials with existing soncrete or substrates. Linking thermal signatures to strength trajectories provides a practical framework for optimizing curing strategies across diverse climates. These findings inform material selection and specification practices for transportation agencies and contractors, enabling rapid‐set concrete repairs that balance early‐opening requirements with long‐term structural performance under varying environmental constraints.

The characteristics of high moisture content, poor compaction, and excessive heavy metal content hinder the reuse of dredged sediment in engineering practice [1]. Meanwhile with the advancement of industrialization, there are still challenges of industrial solid waste large stockpiles and low comprehensive utilization rate in various countries [2]. To collaboratively address these issues, a new low-carbon solid waste-based cementitious material was developed in this study, primarily composed of various industrial solid wastes, including phosphogypsum, slag, and fly ash, for solidifying dredged sediment. The mix proportions of solid waste-based cementitious material were optimized through response surface methodology. Additionally, the mechanical properties, environmental stability, and sulfate corrosion durability of solidified dredged sediment were systematically investigated. The results indicate that the 28d-unconfined compressive strength (UCS) of the optimal solid waste-based cementitious material (PBC) reached 24.65 MPa. Compared with ordinary Portland cement (OPC), the costs and carbon emissions of PBC preparation reduced by 54.86% and 96.84%, respectively. Furthermore, the mechanical and environmental performances of the solidified sediment was comprehensively optimized under the following conditions: 20% binder dosage, 75% moisture content, and an OPC:PBC ratio of 3:7. The new low-carbon binder solidified dredged sediment effectively immobilized fluorine, phosphate, sulfate ion and multiple mental ions, reducing their leaching concentrations, and making them below the limits specified in relevant environmental standards. After 60 days of exposure to a sodium sulfate environment, samples solidified under optimal conditions exhibited no cracking and maintained stable compressive strength. In this presentation, the OPC and PBC composite binder solidified sediment provided a technically feasible and environmentally sustainable approach for the reuse of high moisture content soils in engineering applications.

References:

[1] L. Wang, J.S.H. Kwok, D.C.W. Tsang, C.S. Poon. J. Hazard. Mater. 2014, 283, 623-632.

[2] J. Wu, Y.F. Deng, G.P. Zhang, A.N. Zhou et al. J. Clean. Prod. 2021, 321, 128920.

The pursuit of sustainable construction materials has become a central focus in modern civil engineering, largely due to the pressing need to mitigate the environmental impact of ordinary Portland cement (OPC) production. Cement manufacturing is responsible for a significant share of anthropogenic CO₂ emissions, and reducing this dependency is essential for meeting global carbon reduction targets. One promising approach involves the incorporation of supplementary cementitious materials (SCMs), which can partially replace cement while enhancing resource efficiency and promoting the recycling of industrial by-products.

Lithium slag (LS), a by-product generated during the extraction and processing of lithium, represents a relatively underexplored material with potential applicability in cement and concrete systems. Its chemical and mineralogical composition suggests pozzolanic activity, making it a candidate for integration into structural concrete mixtures.

This study investigated the performance of LS, adjusted to its dried weight (accounting for 24% initial moisture content), as a partial replacement for OPC at 10%, 20%, and 30% by mass in 35 MPa and 45 MPa concretes. The incorporation of LS led to a progressive reduction in workability: slump decreased from 68 mm (control) to 35 mm at 30% replacement in 35 MPa mixes. Early-age mechanical tests at 7 days revealed a decline in compressive strength with higher LS dosages. For 35 MPa concrete, strength reduced from 27.2 MPa (control) to 18.2 MPa at 30% LS, while 45 MPa mixes decreased from 38.3 MPa to 28.9 MPa under the same conditions.

By integrating these findings, the study highlights both the potential and limitations of lithium slag as a supplementary cementitious material. While LS incorporation reduces workability and early strength, it offers a viable pathway for valorizing industrial waste and reducing cement consumption, contributing to more sustainable construction practices.

Introduction

The global plastic crisis, marked by over 460 million tons of annual production and only 9% effective recycling, has accelerated the need for sustainable alternatives to petrochemical-based polymers. Eco-friendly polymers, including biopolymers, geopolymers, and smart/stimuli-responsive polymers, offer a viable path toward reducing environmental impact, supporting the circular economy, and achieving the UN Sustainable Development Goals. Their application spans diverse industries such as electronics, packaging, automotive, aerospace, construction, and biomedical engineering.

Methods

This paper adopts a data-driven review approach, synthesizing recent academic literature, market data, and regulatory frameworks from 2018 to 2024. It focuses on the classification, sources, processing technologies, lifecycle assessments (LCAs), and performance metrics of eco-friendly polymers. Particular attention is given to bio-based polymers (e.g., PLA, PHAs), geopolymers derived from industrial waste (e.g., fly ash, slag), and smart polymers responsive to environmental stimuli (e.g., temperature, pH).

Results

Biopolymers such as PLA and PHAs are widely adopted in packaging, accounting for 38.58% of the biopolymer market revenue in 2023. Their biodegradability, biocompatibility, and versatility support their use in food, cosmetics, and biomedical applications. Geopolymers show high mechanical performance and thermal resistance, making them suitable for construction. Smart polymers enable drug delivery and biosensor applications but face limitations related to response time and stability. Across categories, major challenges include high production costs (20–100% higher than conventional plastics), limited infrastructure for biodegradation and recycling, and regulatory inconsistencies.

Conclusions

Eco-friendly polymers demonstrate significant potential to replace conventional plastics in both high-performance and consumer applications. Their success, however, hinges on overcoming scalability issues, enhancing end-of-life management, and standardizing environmental performance through frameworks such as REACH, TSCA, and ISO 14040/14044. Future progress will depend on interdisciplinary innovation, green chemistry integration, AI-assisted lifecycle assessments, and policy support to enable broader commercialization and a more sustainable material economy.

The escalating environmental challenge posed by plastic waste accumulation necessitates innovative and sustainable solutions within civil engineering. This study investigates the feasibility of utilizing a novel, custom-engineered waste plastic aggregate, derived from post-consumer waste, as a partial replacement for conventional coarse aggregate in an asphalt mixture. The primary objective is to determine the viability of this approach and quantify the impact of the plastic aggregate on the fundamental mechanical and volumetric properties of the asphalt. The methodology involves systematically incorporating the waste plastic aggregate at varying percentages and employing the Marshall mix design method to assess key performance indicators. Critical parameters such as Marshall stability, flow, Marshall quotient, and volumetric properties are determined. The full experimental results comparing the performance of the waste-plastic-aggregate-modified mixtures against the conventional control mix are currently being finalized. Key findings on Marshall stability, flow, Marshall quotient, and volumetric properties will be quantified and presented in detail at the conference, highlighting the performance trade-offs and benefits at different replacement percentages. This study will establish the feasibility of using custom-engineered waste plastic aggregates in asphalt mixtures. It is anticipated that the findings will offer crucial data for developing lighter, more resource-efficient, and environmentally friendly pavement materials. This work aims to advance circular economy principles by providing a viable, large-scale application for non-biodegradable plastic waste in sustainable construction.