Search Results (2,798)

Syngas (synthesis gas) is a promising gaseous biofuel for small-scale power generation, but its highly variable composition, which depends on the biomass source and gasification process, poses challenges for engine optimization. This study investigates syngas–diesel dual-fuel combustion in an optically accessible engine using chemiluminescence imaging of OH*, CH*, and CH₂O* to characterize ignition and flame development. Three representative syngas compositions—Downdraft, Updraft, and Fluidbed—were examined. The Fluidbed composition exhibited the weakest OH* signal, approximately one-third of that observed for the other two, primarily due to its higher CO₂ dilution and lower H₂ content. Ignition delay trends were strongly correlated with dilution level: Downdraft and Updraft showed similar delays despite different H₂/CO ratios, while larger CO₂ shares led to longer delays and flattened heat-release rates. CH* and CH₂O* chemiluminescence showed better agreement with combustion timing than OH*. Methane enrichment enhanced flame propagation and reduced ignition delay, partially offsetting CO₂ dilution effects. Full article

With the constant development of new polymer chemistry technologies, it is necessary to find modern synthetic pathways for the synthesis of polymers bearing numerous applicable characteristics, in an easy, efficient and environmentally friendly way. One such possibility is to present the use of metathesis type reactions and more specifically ring-opening metathesis polymerisation (ROMP), which provides the opportunity to produce linear unsaturated functionalised polymeric chains in a ‘living’ yet controlled manner with the use of ruthenium-based carbene (Ru=CHR) Grubbs’ catalysts (initiators: G1, G2, G3). In order to achieve satisfying results and obtain full conversion of the monomers, sterically hindered molecules are preferred, because the process of opening the ring results in simultaneous release of the energy that propagates the whole process. The incorporation of silicon-based substituents (such as silyl ethers) into the norbornene matrix can provide higher thermal stability of polymers, leading to the creation of flame-retardant materials. Other applications include gas separation membranes or biomedicine, upon further modification. This paper focusses on the development and optimisation of the synthetic method of previously not reported exo-norbornene silyl ethers along with their metathesis polymerisation to achieve linear unsaturated polymers with high isolation yields. Full article

Graphene-based aerogels (GAs) exhibit outstanding performance in the adsorption of organic contaminants. Consequently, numerous studies have investigated the use of GAs for this purpose. In this work, the synthesis methods commonly used to produce GAs are first briefly described, and their key characteristics are summarized. Subsequently, GAs are classified according to the modifications applied to improve their adsorption properties toward organic pollutants. Furthermore, the quantitative relationships between surface area, density, surface chemistry, and adsorption performance for organic contaminants are systematically reviewed. The analysis revealed that the adsorption of two representative organic contaminants, toluene and methylene blue, is not dependent on the surface area of GAs. In contrast, GAs with lower density exhibit an improved adsorption capacity for toluene. Additionally, the relationship between the surface chemistry of GAs and their adsorption capacity toward methylene blue was analyzed considering the concentration of carboxylic sites. The available data suggests a potential correlation between the concentration of carboxylic groups on the surface of GAs and their adsorption capacity for methylene blue. This observation is supported by the analysis of methylene blue species in aqueous solution and the pH at the point of zero charge of GAs, which indicate that the interaction occurs mainly through electrostatic attractions resulting from the deprotonation of acidic surface sites. Finally, several opportunity areas and future research directions regarding the use of GAs for pollutant adsorption are discussed. Full article

Cs₃Cu₂I₅ single crystals are regarded as promising next-generation scintillators due to their large Stokes shift and low self-absorption characteristics. However, the cost-effective solution growth method faces critical challenges: the instability of colloidal precursors in solutions and the severe oxidation of Cu⁺ during crystal growth. This study innovatively introduces yttrium chloride (YCl₃) as a dual-functional additive to address both issues simultaneously. The hydrolysis of YCl₃ creates a controlled acidic environment, effectively suppressing the oxidation of Cu⁺; meanwhile, it enhances the stability of colloidal precursors by significantly increasing their surface charge and narrowing the particle size distribution. These synergistic effects enable the rapid growth (approximately 100 h) of near-centimeter-sized Cs₃Cu₂I₅ single crystals with high crystallinity, without the need for inert gas protection. The optimized crystals exhibit exceptional performance: a photoluminescence quantum yield (PLQY) of 93.22% ± 0.47%, a scintillation decay time of 210.04 ns, and a light yield of ~738.14 pe/MeV. This YCl₃-mediated growth strategy establishes an efficient approach for the solution-based synthesis of high-quality Cs₃Cu₂I₅ single crystals, holding great significance for advancing high-sensitivity, environment-stable radiation detection applications such as medical diagnostics and nuclear safety monitoring. Full article

Standard 16000-8 of the International Organization for Standardization (ISO 16000-8) specifies the assessment of ventilation performance using age-of-air concepts and tracer gas techniques. Since its publication in 2007, ventilation systems and assessment practices have evolved considerably, driven by increased use of mixed-mode and decentralized ventilation and advances in modeling and measurement technologies. This review examines how ISO 16000-8 can be modernized to harmonize with adjacent ventilation and indoor air quality standards while remaining applicable to contemporary systems and emerging approaches. A structured literature search of Web of Science and Google Scholar identified 76 studies (2007–2026) that engage with ISO 16000-8, age-of-air metrics, or tracer gas-based assessment. The literature was synthesized qualitatively using the framework of Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA), classifying studies into performance assessment, measurement–simulation convergence, and standardization discourse. The synthesis shows that while the conceptual foundations of ISO 16000-8 remain valid, assumptions of homogeneous mixing and steady-state conditions are often violated in real buildings, leading to inconsistent application of age-of-air indicators. Field and laboratory studies under point-source conditions demonstrate reduced ventilation effectiveness of 0.73–0.82 in classrooms and 0.5–1.4 in various indoor environments, instead of ≈1 for perfect mixing. Spatial heterogeneity is also observed in mixed-mode systems, with an efficiency around 0.5. In decentralized and façade-integrated systems, air exchange effectiveness deviates from theoretical expectations, indicating inhomogeneous air renewal and short-circuiting. Field measurements show configuration-dependent discrepancies in air exchange rates (e.g., carbon dioxide vs. perfluorocarbon tracer methods under varying door positions), while wind induces time-varying infiltration. Collectively, the literature demonstrates systematic violations of well-mixed and steady-state assumptions underpinning ISO 16000-8. Fragmentation between ventilation performance standards and indoor air quality regulation limits practical uptake. Emerging experimental, numerical, and data-driven methods complement ISO 16000-8, provided applicability domains and uncertainties are addressed. The review concludes that ISO 16000-8 should be modernized toward a harmonized, performance-based framework integrating diverse ventilation systems and assessment technologies. Full article

The guava tree (Psidium guajava L.) is a tropical fruit tree of worldwide importance; however, the salinity of irrigation water severely limits its development in semi-arid regions. However, magnesium (Mg) can mitigate this stress by promoting plant photosynthetic activity. The objective was to evaluate the effect of foliar Mg in mitigating saline stress on photosynthesis and the growth of guava cultivar seedlings. The experiment was conducted in a randomized complete block design, in a 2 × 2 × 3 factorial scheme, with two guava cultivars (Kumagai and Paluma), two irrigation water salinity levels (a low-salinity control—0.5 dS m⁻¹, and salt stress—2.5 dS m⁻¹), and three doses of foliar Mg (0, 1, and 2 mL L⁻¹), and six replications. A salinity of 2.5 dS m⁻¹ reduced growth and gas exchange in both cultivars, with a reduction of approximately 30% in total dry mass, and 16% in CO₂ assimilation rate. Supplementation with 1 mL L⁻¹ of Mg attenuated the effects of stress, stimulating chlorophyll synthesis and gas exchange, reducing approximately leaf temperature in 3.5%, and vapor pressure deficit (VPD) in 12%. The Paluma cultivar was more responsive to Mg under salinity, with improved CO₂ assimilation rate, stomatal control, and water use efficiency. Kumagai showed greater growth in height and diameter with 1 mL L⁻¹ under stress. Foliar application of magnesium (1 mL L⁻¹) is a promising strategy to produce guava seedlings under saline stress. Full article

High-sensitivity rapid detection of ammonia (NH₃) in environmental monitoring, industrial safety, early diagnosis, and other fields is of great significance. Covalent organic frameworks (COFs) have shown great potential in the field of gas sensing due to their designable porous structure and active sites. However, the traditional solvothermal synthesis method of COFs has problems such as cumbersome steps, high energy consumption and serious environmental pollution. Therefore, it is of great significance to invent a new method for COF synthesis that is green and efficient and makes it easy to conduct flexible ammonia gas sensing. This study first reported a solvent-free synthesis of imine connection 1,3,5-Triformylbenzene (TFB) and p-Phenylenediamine (PDA)—a new strategy for COF. This method innovatively employs zinc trifluoromethyl sulfonate (Zn(OTf)₂) as a bifunctional catalyst. This catalyst not only efficiently catalyzes para-phenylenediamine, but its zinc ions also play a unique structural guiding role, guiding the reactants to be arranged in a directional manner, thereby constructing a highly ordered porous crystal structure. A series of characterizations confirmed that the obtained TFB-PDA-COF had good crystallinity and a high proportion of imine bonds (C=N). The powder material was coated onto a flexible polyimide (PI) substrate, successfully constructing a resistive ammonia gas sensor that operates at room temperature. The test results show that this sensor has a high response value, rapid response/recovery capability, and good selectivity for ammonia gas. More importantly, based on a flexible PI substrate, the device can maintain stable sensing performance even under repeated bending conditions, demonstrating its great potential in practical flexible electronic applications. This work not only provides a brand-new “zinc ion-guided” paradigm for the green and controllable synthesis of COF but also lays a material foundation for their application in the next-generation flexible sensing field. Full article

Ecosystem disruption is a significant challenge of the contemporary age, arising from substantial CO₂/CO emissions resulting from dependence on fossil fuels as a primary energy source. Scholars across several fields are striving to mitigate these severe greenhouse gas emissions. The most promising method is to adsorb carbon and convert it into sustainable energy. We sought to diminish CO levels by electrocatalytic reduction using innovative catalytic surfaces, namely transition metal phosphides (TMPs). During this work, VP is recognized as a very effective surface for CO reduction and the synthesis of formaldehyde, methanol, and methane at −0.68 V. Further, hydrogen evolution reaction (HER) does not pose a challenge for any surface, despite all TMPs facilitating CO reduction. In summary, predictions derived from this density functional theory (DFT)-guided analysis provide experimentalists with insights to validate experiments and synthesize active catalysts for CO conversion and green energy generation. Full article

With changes in the global energy structure, ammonia has emerged as a favorable hydrogen storage medium due to its excellent properties. This work details the synthesis of a barium-doped cobalt–iron alloy catalyst via subsequent heat treatment. This alloy efficiently catalyzes the decomposition of ammonia into hydrogen. The results showed that using characterization methods such as TEM and XRD indicated that adding Ba to this system could regulate the microstructure of the Co-Fe alloy. After calcination, the barium promoted a reduction in the particle size of Co-Fe nanoparticles, enabling their uniform dispersion on the surface and a more uniform dispersion and improving the accessibility of the exposed surface. The optimized catalyst (0.05Ba-0.25CoFe/CeO₂) achieved an ammonia conversion of 93.2% at 550 °C under a gas hourly space velocity of 30,000 mL·g_cat⁻¹·h⁻¹. Mechanistic analysis based on XPS and CO₂-TPD results indicated that the barium optimized the electronic structure and alkaline sites of Co-Fe, promoted the desorption of nitrogen, and thereby accelerated the reaction kinetics of ammonia decomposition. This research provides a strategic method and theoretical basis for designing high-performance non-precious metal catalysts for ammonia decomposition. Full article

Oilfield worksites and the communities shaped by them are increasingly recognized as gendered spaces in which rotational labor, contractor hierarchies, and production imperatives can reshape norms of accountability and consent. This scoping review synthesizes conceptualizations of oilfield masculinities in scholarship on oil and gas extraction and examines their links to gendered harm, moral strain, and institutional accountability. Following PRISMA-ScR guidance, multidisciplinary databases were searched for English-language publications (2000–March 2024); eighteen sources met the inclusion criteria. A supplementary media scan (2000–2025) was conducted to contextualize cultural narratives surrounding oilfield labor. The synthesis identifies recurring themes, including frontier and breadwinner masculinities, emerging safety-oriented masculinities, gendered workplace exclusion, and the relational impacts of rotational absence and reintegration. Across studies, harms are most consistently described as patterned outcomes of work organization and fragmented governance rather than isolated incidents. Media representations frequently amplify heroism and endurance while minimizing institutional responsibility. Full article

Research on hydrogen production by chemical methods has focused on combining metals to carry out the hydrolysis reaction under ambient conditions. In particular, aluminum and lithium metals were considered, with lithium used at low concentrations in order to activate aluminum. Under these conditions, the metals can react with water to obtain the maximum hydrogen yield. The main objective of this work was to prepare the lithium−aluminum alloy by mechanical milling and its chemical reaction with water to produce hydrogen under laboratory conditions. A high–energy Spex mill was used for material preparation and the time scheduled for alloys preparation was relatively short. Several techniques were used for its characterization, such as X–ray diffraction, scanning electron microscopy, gas chromatography, and low-temperature physical adsorption. According to the results, two phases were produced during the milling process when using 5% lithium. The volume of hydrogen generated was measured using a graduated burette. Depending on the volume obtained, the aluminum reacted to generate hydrogen with an efficiency of 95.24%. No additives or catalysts were used in material synthesis or hydrogen production. According to these results, the hydrogen does not require any purification because it is clean hydrogen and can therefore be used directly in fuel cells. Full article

Asphalt pavements are essential to modern transport infrastructure but remain highly dependent on virgin aggregates and petroleum-based binders, resulting in high energy demand and significant greenhouse gas emissions. In response, research has advanced recycled-material solutions and low-temperature asphalt technologies. However, sustainability is still often inferred from isolated environmental indicators, without consistent consideration of mechanical durability or economic feasibility throughout the life cycle. This review provides an integrated synthesis of sustainable asphalt mixtures by jointly examining recycling strategies, temperature-reduction processes (warm-mix, half-warm-mix, and cold-mix asphalt technologies), and their combined applications through an integrated performance–cost–environment perspective. The literature reveals substantial methodological fragmentation, with limited harmonisation of functional units, system boundaries, and allocation rules, which constrains cross-study comparability. Evidence indicates that reclaimed asphalt, recycled concrete aggregates, and steel slag can maintain or improve rutting resistance, stiffness, and moisture durability while enabling material cost savings of approximately 5–68%. Temperature-reduction technologies further achieve significant energy and GHG reductions in the production phase (20–70%), with integrated recycling–temperature-reduction systems showing the most consistent combined benefits. Overall, this review demonstrates that asphalt sustainability cannot be established through single-dimensional assessments but requires harmonised life-cycle frameworks that explicitly link environmental gains to mechanical performance, durability, and economic viability. Full article

The study of wide-bandgap nanomaterials has gained considerable attention in recent years, especially in the case of semiconductor oxides that exhibit full or partial optical transparency in fundamental research and technological applications. These include optoelectronic devices, gas sensors and photovoltaic cells, among others. The activation or adjustment of optical and structural properties, especially the bandgap and the parameters of unit cell lattice, can be achieved by varying the dopant concentration during the synthesis of semiconductor thin films in these applications. In this context, copper oxide has emerged as a valuable material, owing to its thoroughly analyzed structural behavior and its broad potential across multiple technological fields. The present work focuses on the synthesis of zinc-doped copper oxide (Zn_xCu_1−xO) thin films on silicon and quartz substrates through ultrasonic spray pyrolysis. The effects of varying the zinc doping concentration (0.0, 5.0, 10.0 and 20.0 at. %) on the morphological, structural, and optical characteristics of the Zn_xCu_1−xO films were analyzed. Scanning electron microscopy (SEM) analysis indicated a gradual increase in nanoparticle size, rising from 221 nm for CuO to approximately 322 nm for the Zn_0.2Cu_0.8O samples as the zinc content increased. Structural characterization via X-ray diffraction (XRD) confirmed a monoclinic crystal arrangement belonging to the $C_{2h}^6$ (c2/c) space group. As the percentage of zinc increased, the XRD peaks shifted to lower angles, consequently increasing the volume and crystal lattice parameters of the Zn_xCu_1−xO structure; this finding was additionally supported by a redshift observed in the Raman analysis. The transmittance spectra of the films showed low transmittance between 40 and 44%. The optical bandgap of the Zn_xCu_1−xO thin films was estimated from the transmittance data by applying the Tauc plot method. A decrease in the band gap was observed at higher doping concentrations. It can be confirmed that no secondary phases are observed at a doping level of 20.0 at. % of zinc, indicating good solubility of zinc in CuO. The analysis and discussion of these findings are included throughout this work to elucidate the controversies noted in the literature. Full article

Lightweight high-entropy alloys are primarily designed to overcome the strength-to-density ratio limitations of conventional counterparts and often consist of elements with drastically different melting temperature and vapor pressure. Their chemistry, therefore, imposes challenges on alloy synthesis, particularly through liquid metal engineering routes, since elements with high vapor pressure (e.g., Mg, Zn, Li) vaporize before the higher-melting-point ingredients (e.g., Cu, V, Ni) are fully molten, resulting in volatile element loss. To overcome this challenge, a novel pressure-assisted induction melting (PAIM) process was developed and the proprietary furnace for its implementation was designed and built. The system allows precision melting of up to 10 cm³ of an alloy at temperatures up to 1700 °C while addressing the partial pressure requirements during the melting progress. The chamber is prepared using rough vacuum and re-filled with inert gas such as argon with the operating pressure range from about 10⁻⁴ MPa up to maximum of 1.6 MPa (233 psi). The alloy chemical composition can be modified in situ by feeding solid additives at specific melting stages through the isolated airlock without disrupting the pressure conditions within the chamber. The viability of the concept was verified by synthesis of two lightweight non-equimolar high-entropy alloys: Mg-rich Mg₅₀(MnAlZnCu)₅₀ and Al-rich Al₃₅Mg₃₀Si₁₃Zn₁₀Y₇Ca₅. The experiments showed that sequential multi-step melting procedures, designed based on inputs from FactSage computational analysis, when combined with PAIM synthesis, allowed manufacturing fully dense and chemically homogenous complex alloy compositions with optimal volumes for materials discovery research. Full article

The growing diversity of anthropogenic chemicals in the environment far exceeds the scope of routine analytical monitoring. Non-target screening (NTS) using high-resolution mass spectrometry (HRMS) has thus emerged to discover unknown organic contaminants. Liquid or gas chromatography (LC/GC) coupled with ion mobility–mass spectrometry (IM-MS) further enhances NTS by providing multidimensional, structurally informative data. Machine learning (ML) offers a powerful solution by efficiently processing high-dimensional data and uncovering patterns. Both supervised and unsupervised learning approaches show strong potential to streamline labor-intensive processes. This review provides an overview of key ML algorithms and representative workflows in LC/GC-(IM-) MS-related NTS, followed by a critical synthesis of recent advances in ML-enabled applications across the entire NTS procedure, from sample analysis to data acquisition, and ultimately risk assessment. Continued advances in ML are expected to transform NTS into a more efficient and robust tool for risk assessment. Full article