Search Results (59)

Essential oils are complex plant-derived volatile blends composed of a myriad of aromatic secondary metabolites. The volatile architecture of plant essential oils suggests a consistent trend under the experimental conditions evaluated, regardless of the distillation scale and methodology. This study presents a comparative chemometric evaluation of two integrated processing systems: laboratory-scale hydrodistillation (HD) of dried biomass versus semi-industrial-scale dry steam distillation (SD) of fresh biomass. Seven economically important botanical species spanning three families were analyzed: Lavandula angustifolia, Salvia officinalis, Hyssopus officinalis, Mentha piperita, Mentha spicata, Achillea millefolium, and Picea abies. Gas chromatography–mass spectrometry (GC-MS) profiling revealed that HD consistently yielded a more chemically diverse volatile profile than SD. Unsupervised Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) achieved absolute binary segregation between the HD and SD fractions for every species. Supervised Partial Least Squares Discriminant Analysis (PLS-DA) established robust predictive models (Q² cum > 0.98), isolating specific chemical markers responsible for the variance. The results prove a universal physical trend: HD significantly enriched low-boiling oxygenated derivatives (such as oxygenated monoterpene alcohols and oxides), while SD selectively preserved heavier, thermally sensitive hydrocarbon fractions across all taxonomic groups. Ultimately, combining GC-MS with multivariate chemometrics provides an objective, automated framework for quality control, authentication, and industrial process optimization in the essential oil sector. Full article

The increasing use of biodegradable polymers, especially poly (lactic acid) (PLA), has raised concern about their entry into conventional post-consumer recycling streams. This review examines the technical and systemic consequences of PLA contamination in the high-density polyethylene (HDPE) circular economy through the “drop-in delusion,” defined here as the mistaken assumption that a sustainability-marketed polymer can enter an established recycling stream without compromising system compatibility. Focusing on contamination-sensitive conditions in which segregation, sorting, or stream purity are insufficient to prevent cross-contamination, the review discusses the immiscibility of HDPE/PLA blends and the resulting changes in stiffness, ductility, toughness, and aging behavior. It also analyzes mitigation routes such as improved sorting, compatibilization, and policy measures, while emphasizing that the practical severity of contamination depends on local infrastructure and contamination levels. In addition, it considers the risk that contaminated materials diverted into lower-value applications may become more vulnerable to interfacial damage, weathering, and secondary fragmentation. Overall, the review argues that circular-plastics strategies must distinguish biodegradability from recycling-system compatibility to protect the quality and value of HDPE recyclates. Full article

Duplex stainless steel (DSS) blends impressive mechanical and chemical characteristics to withstand aggressive environments. Its fabrication by Gas Metal Arc Welding-Additive Manufacturing is an emerging research topic. However, its sensitive grain structure and alloy composition are prone to deterioration by repeated thermal shocks. Whether optimal weld parameters can resolve these challenges without additional costs from special fillers, gases, or mechanisms is a valid question. In this study, how different wire feed speeds, travel speeds, and weld voltages, chosen from a set of preliminary beads, translate into wall dimensions, phase formation and distribution, morphological transformation, and elemental segregation is investigated. The unique DSS microstructures were characterised using scanning electron microscopy and energy-dispersive spectroscopy to reveal differences in microstructural evolution and ferrite-austenite (α-γ) structure. The deposited walls exhibited satisfactory geometric quality with negligible distortions. However, the height suppression was noticeable at the deposition energy (DE) of 755 J/mm. Metallographic analysis revealed low γ phase formation (<30%) at low DE (230 J/mm) and excessive γ formation (>70%) in the high DE wall (755 J/mm). The parameters WFS:TS = 15, TS = 35 cm/min, WFS = 525 cm/min, and V = 20.804 volts suppressed the elemental segregation while maintaining a suitable phase balance without post-processing. Full article

In this study, we investigate the impact of processing strategies on the nanoscale morphology and photophysical behavior of donor–acceptor thin films composed of the polymeric donor PBDTTTPD and the n-type acceptor PNDI(2HD)2T. The blend morphology and interfacial characteristics were systematically tuned using three distinct fabrication techniques: spin-coating, convective self-assembly, and space-confined solvent vapor annealing. Atomic force microscopy and photoluminescence spectroscopy were employed to elucidate structure–property correlations relevant to all-polymer optoelectronic systems. Films processed via convective self-assembly exhibited nanoscale features with extensive donor–acceptor intermixing, leading to the most efficient photoluminescence quenching of nearly 85%, indicative of enhanced exciton dissociation and charge transfer. In contrast, as-cast films displayed moderately mixed morphologies with approximately 81% quenching, serving as a reference state. The solvent vapor annealing method induced pronounced phase segregation and the formation of larger domains, resulting in reduced photoluminescence quenching efficiency of about 52%. These findings demonstrate that the nanoscale morphology, and consequently the photophysical response, of PBDTTTPD:PNDI(2HD)2T blends can be precisely tailored through processing, providing valuable design guidelines for all-polymer optoelectronic applications such as organic photovoltaics and field-effect transistors. Full article

Indonesia, as a major global textile exporter, faces substantial sustainability challenges due to its linear production model, which generates massive volumes of post-industrial polyester waste (PIPW). However, reliable data and recycling pathways remain critically lacking. This study quantifies the volume, composition, and textile-to-textile (T2T) recyclability potential of PIPW across Indonesia’s national textile and clothing production chain, employing a mixed-methods approach that integrates material flow analysis (MFA), site visits, and stakeholder interviews. The results indicate that 572 kilotonnes of PIPW were generated in 2023, with garment manufacturing identified as the most waste-intensive. Nineteen waste types were identified; 61% comprise fibre blends, which significantly constrain closed-loop recycling. A novel five-tier waste typology was developed to classify waste streams based on material characteristics, technological availability, and economic feasibility. The circularity map reveals that Indonesia is trapped in pseudo-circularity. Scenario analysis suggests that up to 184 kilotonnes of PIPW could be feasibly redirected towards higher-value chemical recycling. The research recommends mandatory source segregation, fiscal incentives, investment in chemical recycling infrastructure, and the integration of circular design into national standards. The study provides the first national-level MFA of PIPW in Indonesia and establishes an empirical baseline to advance T2T recycling in emerging economies. Full article

The Compact Strip Production (CSP) process is the latest version of thin-slab continuous casting, combining both casting and rolling, thus improving the CSP process’s energy efficiency and the strip quality. Modeling the combined phenomena of fluid flow, heat transfer and solidification in CSP casting remains an unresolved multiphysics problem, particularly when boron and other alloying elements enter the system and modify the thermal properties and solidification behavior. In this study, we propose a more integrated approach by executing a computational fluid dynamics (CFD) model at different scales, blending macroscale fluid flow and heat transfer with meso-solidification that is molten in a CSP casting model. For the macroscale model, we solve the Reynolds-Averaged Navier–Stokes (RANS) equations with one of the energy equations, while the mesoscale model uses the solid fraction evolution algorithm to model the multiphase latent heat of solidification and the motion of solid and liquid phases of a non-equilibrium system. Mold heat flux, free surface cooling and secondary spray zones were used to set the boundary conditions. The model simulates temperature distributions at different times, the solid fraction below the liquidus and the trends in shell growth for different process parameters and the time profile of the solidification. The improved prediction capability of the model, demonstrated by the results, opens the opportunity to reduce the process parameters of casting speed and cooling to defect-free results. Comparisons with the most recent studies on continuous casting processes (including CSP and thin slabs) demonstrate alignment with the thermal gradient and solidification behavior characteristics. The thermal gradients and solidification behavior characteristics were obtained. The research yields the basis for developing microstructure and segregation models with boron-alloyed steels. Full article

Improving both the high- and low-temperature performance of asphalt is still difficult in modern pavement applications. This performance imbalance has motivated the development of new modification strategies that can enhance temperature stability while maintaining construction workability. In this research, a low-molecular-weight elastic polyolefin (POL) with inherent compatibility was introduced as a novel asphalt modifier. POL was incorporated at five dosages (0%, 2%, 4%, 6%, and 8% by weight of asphalt) to investigate its effects on the fundamental physical, rheological, and low-temperature properties of the asphalt. The rheological behavior was characterized by dynamic shear rheometer (DSR) and bending beam rheometer (BBR), while the modification mechanism and dispersion morphology were analyzed through Fourier-transform infrared spectroscopy (FT-IR) and fluorescence microscopy (FM). The results reveal that POL markedly improves the high-temperature performance and workability of asphalt, with the rutting factor increasing by two- to eightfold. POL modification improved the thermal stability of asphalt, shifting the maximum decomposition temperature from 455.2 °C for the base binder to 461–463 °C, while the total mass loss remained nearly constant at 80–83%. Microscopic observations confirm that POL forms a physically blended network within the asphalt matrix, exhibiting a green fluorescent structure that becomes progressively continuous with increasing dosage. The most homogeneous dispersion and optimal compatibility occur at a POL dosage of 6%, beyond which phase segregation emerges and low-temperature properties deteriorate. Accordingly, a 6% POL dosage is recommended for achieving balanced performance. These findings provide theoretical and practical guidance for the development of balanced performance and thermally stable POL-modified asphalt materials. Full article

Volcanic Scoria Lightweight Aggregate Concrete (VSLAC) has been identified as a material with considerable potential for use in carbon-neutral construction; however, its application is often hindered by two main issues. Firstly, the low density of scoria often results in aggregate segregation and stratification. Secondly, its high hygroscopicity can lead to shrinkage cracking. In order to address the aforementioned issues, this study proposes a multi-scale modification strategy. The cementitious matrix was first strengthened using a binary blend of Fly Ash and Ground Granulated Blast Furnace Slag (GGBS), followed by the incorporation of a ternary admixture system containing Styrene-Acrylic Emulsion (SAE), a foaming agent (FA), and alkali-treated Straw Fibres (SF) to enhance workability and durability. The findings of this study demonstrate that a mineral admixture comprising 10% Fly Ash and 10% GGBS results in a substantial enhancement of matrix compactness, culminating in a 20% increase in compressive strength. An orthogonal test was conducted to identify the optimal formulation (D13), which was found to contain 4% SAE, 0.1% FA, and 5% SF. This formulation yielded a compressive strength of 35.2 MPa, a flexural strength of 7.5 MPa, and reduced water absorption to 8.0%. A comparative analysis was conducted between the mineral admixture mix ratio (Control group) and the Optimal mix ratio (Optimization group). The results of this analysis reveal that the Optimization group exhibited superior durability and thermal characteristics. Specifically, the water penetration depth of the optimized composite was successfully restricted to within 3.18 mm, while its thermal insulation performance demonstrated a significant enhancement of 12.3%. In the context of freeze–thaw cycles, the modified concrete demonstrated notable durability, exhibiting a 51.4% reduction in strength loss and a marginal 0.64% restriction in mass loss. SEM analysis revealed that the interaction between SAE and the FA resulted in the densification of the Interfacial Transition Zone (ITZ). In addition, the 3D network formed by SF redistributed internal stresses, thereby shifting the failure mode from brittle fracture to ductile deformation. The findings demonstrate that modifying VSLAC at both micro- and macro-levels can effectively balance structural integrity with thermal efficiency for sustainable construction applications. Full article

Expanded polystyrene (EPS) waste was chemically modified by sulfonation to obtain sulfonated EPS (sEPS), which was subsequently blended with virgin polyphenylsulfone (PPSU) at concentrations ranging from 10 to 50% to elaborate hollow fiber membranes for dye removal. The membranes were elaborated by non-solvent-induced phase separation and characterized by scanning electron microscopy, mechanical properties, antifouling, water flux measurements, and dye rejection performance. Scanning electron microscopy images of PPSU/sEPS blends showed well-defined membrane cross-sections with no polymer segregation up to 30% recycled EPS content, indicating improved compatibility due to EPS sulfonation. The HFMs present mean pore radii ranging from 4.2 ± 0.5 to 11.1 ± 1.0 nm with porosity up to 80%. Water flux improved significantly from 3.1 to 21.2 L m⁻² h⁻¹ at 2 bar as sEPS content increased. Dye rejection performance was promising, with Reactive Black 5 rejection ranging from 77% to 99%. The 80/20s PPSU/sEPS membrane showed the highest Reactive Black 5 rejection at 98.3% and revealed a 70.3% rejection in a 24 h dye mixture test. Furthermore, the 70/30s displayed superior anti-fouling properties, achieving a 99.3% flux recovery ratio in a xanthan gum solution at 2 bar. This study demonstrates a novel approach to transform EPS waste into high-performance hollow fiber membrane with competitive antifouling and dye separation properties. Full article

The present study aimed to determine whether enriching the finishing ration of lambs with incremental doses of a protected fatty acid (FA) blend would result in noticeable differences in the eating experience of the resulting meat. Three isonitrogenous diets containing 0, 50, or 100 g day⁻¹ of the FA mixture were formulated, and the lambs were fed these diets until slaughter under otherwise identical management conditions. After postmortem aging, boneless loin samples from each treatment were submitted to a descriptive sensory evaluation by a rigorously trained panel that followed international guidelines. Multivariate techniques—principal component analysis combined with hierarchical clustering—were applied to integrate the panel’s quantitative scores and visualize how the treatments segregated in sensory space. The lamb meat presented a level of acceptance dependent on the proportion of fatty acids. In general, this study suggests that adding an extra 50 or 100 g of fat supplement to a lamb’s diet towards the end of its growth can significantly improve the enjoyment consumers get from eating the meat. Sensory analysis of lamb meat enriched with fatty acids indicated that the most important attributes determining the acceptance of lamb meat were color, flavor, odor, and toughness. Consequently, it can be recommended that dietary fatty acids be strategically increased during the finishing phase as a practical approach to enhancing the sensory appeal of sheep meat without compromising panel consensus. Full article

Epoxy asphalt is a superior polymer-modified asphalt material; however, significant differences in physicochemical properties, such as solubility parameters and dielectric constants, between epoxy resin and asphalt have led to compatibility issues that hinder its development. This study employed molecular dynamics simulations to investigate the effect of maleic anhydride-grafted styrene-butadiene-styrene (MAH-g-SBS) on the compatibility of epoxy asphalt. By analyzing parameters such as cohesive energy density, solubility parameters, energy distribution, interaction energy, radial distribution function, free volume fraction, and mean square displacement, the molecular mechanism underlying the enhanced compatibility was elucidated. The results indicate that the amphiphilic molecular structure of MAH-g-SBS significantly improves the thermodynamic compatibility between asphalt and epoxy resin, enhances interfacial affinity and stability, reduces the system’s total interaction and nonbonded energies, facilitates the dispersion and permeation of epoxy molecules into asphalt, and increases molecular mobility, thereby comprehensively enhancing the compatibility of the epoxy asphalt blend. Segregation tests and fluorescence microscopy further verified the simulation results, demonstrating that MAH-g-SBS improves the storage stability and phase uniformity of the epoxy asphalt system. Full article

A novel strategy has been developed for extracting value-added resources from iron-lean, high-alumina- and -silica-containing red muds (RMs). With little or no recycling, such RMs are generally destined for waste dumps. Detailed results are presented on the carbothermic reduction of 100% RM (29.3 wt.% Fe₂O₃, 22.2 wt.% Al₂O₃, 20.0 wt.% SiO₂, 1.2 wt.% CaO, 12.2 wt.% Na₂O) and its 2:1 blends with Fe₂O₃ and red mill scale (MS). Synthetic graphite was used as the reductant. Carbothermic reduction of RM and blends was carried out in a Tamman resistance furnace at 1650 °C for 20 min in an Ar atmosphere. Reduction residues were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), elemental mapping and X-ray diffraction (XRD). Small amounts of Fe₃Si alloys, alumina, SiC and other oxide-based residuals were detected in the carbothermic residue of 100% RM. A number of large metallic droplets of Fe–Si alloys were observed for RM/Fe₂O₃ blends; no aluminium was detected in these metallic droplets. A clear segregation of alumina was observed as a separate phase. For the RM/red MS blends, a number of metallic Fe–Si droplets were seen embedded in an alumina matrix in the form of a cermet. This study has shown the regeneration of alumina and the formation of alumina-based cermets, Fe–Si alloys and SiC during carbothermic reduction of RM and its blends. This innovative recycling strategy could be used for extracting value-added resources from iron-lean RMs, thereby enhancing process productivity, cost-effectiveness of alumina regeneration, waste utilization and sustainable developments in the field. Full article

The processing of dimension stones for the construction sector involves transforming rock blocks into slabs via sawing and polishing. This process generates a fine-grained waste composed largely of rock powder derived from the processed rock. Several studies indicate that the rock powder produced as a processing waste can release Ca, Mg, and K. However, alongside the release of macronutrients, there is the possibility of releasing undesirable constituents, such as Na, which is also a component of the minerals forming silicate rocks. This study aimed to analyze the risk of salinization that these materials may cause to soil if applied without a thorough evaluation of their composition. Samples were analyzed in terms of physical, chemical, and mineralogical parameters; exchangeable inorganic constituents; percentage of exchangeable sodium; and sodium adsorption ratio. The data indicate that residues stored in landfills in a random and unsorted manner do not fully meet the criteria established by Brazilian regulations for soil remineralizers. However, their characteristics suggest good potential for use in the agricultural sector, although this would require blending with other agricultural inputs and/or segregating residues from certain types of rocks to comply with current regulations. Full article

The large-scale production of waste plastics has brought serious environmental pollution problems and its recycling and high value-added utilization technology remains a global challenge. Therefore, this study uses waste polyethylene (PE) to prepare high-performance polyethylene composite modified asphalt (HPEA), solving the problem of poor stability and low temperature performance of traditional plastic modified asphalt, while achieving high value-added utilization of waste plastics. A high-performance polyethylene composite modifier (HPE) was prepared through mechanochemical and thermochemical interactions. Then HPEA with different HPE content and styrene-butadiene-styrene (SBS) modified asphalt (SBSMA) with different SBS content were prepared. Compare and analyze the conventional performance, storage stability, anti-aging performance and microscopic properties of HPEA and SBSMA. The results are as follows: (1) the conventional performance of HPEA is comparable to, or superior to, that of SBSMA. The addition of HPE resulted in a significant decrease in asphalt penetration. The modification effect achieved by adding 3–5% SBS to Kunlun 70# asphalt is equivalent to that achieved by incorporating 4–6% HPE. (2) HEPA exhibits good storage stability and no obvious segregation phenomenon. When the HPE content changes from 4% to 8%, the maximum difference in 48 h softening point of HPEA is 1.1 °C, which is significantly smaller than the 48 h softening point difference of SBSMA when the SBS content changes from 3% to 5%. (3) When HPE attains a specific concentration, HPEA can exhibit an anti-aging performance that is comparable to, or superior to, that of SBSMA. (4) The infrared spectrum of HPEA closely resembles that of SK70# matrix asphalt. The modification of HPEA primarily involves physical blending, with HPE undergoing development and re-crosslinking within the system, leading to interactions between smaller particles and asphalt, resulting in the formation of a relatively stable three-dimensional spatial structure. Full article

The Xiaorequanzi Cu deposit is located in the western part of the Dananhu–Tousuquan Island arc in eastern Tianshan, Xinjiang. It includes stratiform and epithermal-related veinlet mineralization. However, the genesis of this deposit remains controversial. Therefore, fluid inclusions, H–O isotopes, in situ S, and trace elements in pyrite were employed in this study to constrain the origins of the deposit. The Xiaorequanzi Cu deposit’s mineralization stages can be categorized into the following three phases: I. volcanogenic massive sulfide (VMS) mineralization; II. quartz–chalcopyrite–pyrite; and III. quartz–chalcopyrite–sphalerite stages. Fluid inclusion studies suggest that Stage I is distinguished by high-temperature (peak: 320–360 °C) and moderate-salinity (peak: 7–9 wt%) fluids belonging to the H₂O–NaCl ± CO₂ system. Stages II–III only exhibit vapor–liquid inclusions, with mineralizing fluids belonging to the medium-to-low-temperature (Stage II peak: 160–180 °C; Stage III peak: 120–130 °C) and medium-to-low-salinity (Stage II peak: 5–7 wt%; Atage III peak: 4–6 wt%) H₂O–NaCl system. The H–O isotopic data suggest that mineralizing fluid in Stage I is a blend of magmatic and paleo-seawater sources, while in Stages II–III, meteoric water predominates, accompanied by low mineralizing temperatures. In situ S isotope results indicate that the source of mineralizing materials in Stage I (2.52–4.48‰) were magmatic rocks, whereas the markedly higher δ³⁴S values in stages II–III (4.68–6.60‰) suggest sulfur isotope leaching from sedimentary rocks by meteoric water as the main source. The LA–ICP–MS data of pyrite in the Xiaorequanzi Cu deposit suggest that Py₁ was formed through volcanic processes, whereas Py₂ and Py₃ exhibited epithermal characteristics. Throughout the mineralization process, a trend in increasing oxygen and decreasing sulfur fugacity occurred, accompanied by a decreased mineralization temperature. This observation corresponds with the temperature data derived from the fluid inclusions. Additionally, the principal components of different generations of pyrite segregated as two clusters representing the VMS (Stage I) and epithermal mineralization (stages II–III). In summary, based on comprehensive research and previous geochronological studies, it is suggested that the Xiaorequanzi Cu deposit experienced two mineralization stages. The early stage is related to the volcanic activity of the Early Carboniferous (354 Ma), whereas the later stage is associated with Carboniferous–Permian (266–264 Ma) volcanic intrusions. Full article