Search Results (2,004)

This study investigates the influence of bottom ash (BA) and marble dust powder (MD) as partial replacements for Ordinary Portland Cement (OPC) on the physical, mechanical, and mass loss performance of cement pastes under cyclic seawater exposure and their economic feasibility. Mixtures containing 0–20% BA and 0–20% MP were tested to evaluate their workability, strength, porosity, durability, and cost efficiency. The results indicate that BA reduces workability, which is reflected in the lower slump values of mixtures with a higher BA content, whereas MD enhances fluidity by filling the voids between particles and improving the packing density of the mixture, which results in better workability. The optimal composition, which was 15% bottom ash and 10% marble dust powder, achieved a superior mechanical performance, with compressive strength (CS) and flexural strength (FS) increases of 2.2% and 38.7%, respectively, at 28 days compared to the control. Increasing the BA and MD content up to a total of 35% of the binder generally led to a moderate reduction in early-age strength, while mixtures with 20% replacement exhibited comparable or improved long-term strength at 90 days. This led to decreased porosity and improved long-term mass loss performance under cyclic seawater exposure. The incorporation of BA and MD also reduced water absorption, indicating enhanced durability, with these beneficial effects becoming more pronounced at later ages. Economically, cement substitution with BA and MD reduced production costs by up to 39.6%. In summary, moderate incorporation of BA and MD enhances performance, reduces cost, and supports the sustainable utilization of industrial waste in cementitious materials. The mixture proportions investigated in this study offer a promising alternative binder for use in the sustainable building sector. Full article

This study investigated the development of a perlite waste-based geopolymer for stabilizing iron ore tailings byproduct (IOTB) for geotechnical applications. Mixtures containing 70/30 and 80/20 proportions of byproduct and geopolymer were produced using perlite waste as the precursor and NaOH as the alkaline activator through the one-part method. Raw and geopolymer-stabilized IOTB, air-cured for 7, 14, and 28 days, were evaluated by ICP-OES, XRF, pH, geotechnical characterization, compaction, permeability, SEM, and consolidated drained triaxial tests under confining stresses ranging from 250 to 2000 kPa. The selected mixture presented a maximum dry density of 1.8 g/cm³ and optimum moisture content of approximately 14%. XRD results indicated sodium aluminosilicate phases associated with geopolymerization, with mechanical characteristics comparable to feldspar-type structures, while the pH increased from 6.5 to 12.5. Triaxial tests indicated that elastoplastic behavior persisted regardless of the geopolymer addition; however, SEM images confirmed matrix–particle bonding at grain contacts without significant pore filling. The cohesive intercept increased from 0 kPa in the IOTB to 89.1 kPa and 179.2 kPa after 14 and 28 days of curing, respectively, while the friction angle showed a slight increase of up to 7.7%. Deviatoric stress at failure and energy absorption capacity also increased with curing time. Hydraulically, the permeability coefficient remained within the same order of magnitude (10⁻⁴ cm/s), varying from raw IOTB of 2.73 × 10⁻⁴ cm/s to 3.28 × 10⁻⁴ cm/s after 28 days. These results demonstrated that geopolymer stabilization enhanced mechanical performance without compromising drainage capacity, representing a technically viable and socio-environmentally sustainable solution. Full article

This study evaluated the susceptibility of common bean (Phaseolus vulgaris L.) cultivars to Euschistus heros feeding across various phenological stages. Three cultivars (IPR Curió, IPR Sabiá, and IPR Urutau) were infested with 0.5 insects per plant for eight days starting at anthesis and 8, 16, 24, 32, and 40 days after flowering (DAF) using a randomized block design with five replicates. E. heros did not significantly impact grain yield or reproductive abscission, except for the IPR Curió cultivar during flowering, which demonstrated substantial qualitative damage. Feeding injury resulted in increased grain punctures and the grading of commercial classification to Type 2. The most critical susceptibility period occurred during the grain-filling stages (16–24 DAF). IPR Curió was the most sensitive cultivar, exhibiting Type 2 status at both 16 and 24 DAF. These findings demonstrate that although common beans exhibit quantitative tolerance to E. heros at the tested density, qualitative damage during grain development significantly compromises marketability and value. Integrated Pest Management (IPM) should prioritize protecting the crop during mid-to-late reproductive stages to ensure that grain quality standards are met. Full article

The increasing utilization of radiation in medicine, industry, and water purification highlights the need for efficient radiation-protection materials. This study investigates lead-free polymer composites based on high-density polyethylene (HDPE) filled with four metallic fillers: tungsten carbide (WC), molybdenum carbide (MoC), tungsten (W), and molybdenum (Mo) at 15 wt%. The objective is to evaluate their potential as alternatives to lead for shielding ionizing radiation. Mechanical performance was examined through tensile testing, while thermal stability was assessed based on the residual mass. Radiation-attenuation behavior was analyzed through linear and mass attenuation coefficients (µ and µₘ), radiation protection efficiency (RPE), half-value layer (HVL), mean free path (MFP), buildup factors (B), and effective atomic number (Z_eff) within the 47.9–248 keV energy range. The HDPE/W composite exhibited the greatest enhancement, with a mass attenuation coefficient (µₘ) 82.5% higher than that of pure HDPE, along with the highest linear attenuation coefficient (µ). Furthermore, tungsten-loaded samples achieved an RPE of 98.05% at 47.9 keV. The increased density, low B, and high Z_eff values collectively contribute to superior shielding performance. These findings indicate that HDPE filled with WC, MoC, W, and Mo are promising lead-free candidates for low-energy X-ray shielding applications. Full article

Drip fertigation (DF) is increasingly adopted to improve winter wheat productivity, yet its interactions with planting density (PD) and the underlying source–sink mechanisms remain insufficiently quantified. Here, we evaluated winter wheat performance under two water–nitrogen (N) regimes—conventional management (CM) and DF—across a wide PD gradient (100–800 seeds m⁻²) during two growing seasons. Grain yield, yield components, population traits, dry matter production, source–sink indices, canopy N status, N uptake and N-use efficiencies were assessed. Across seasons, DF increased grain yield by 15.4–20.8% relative to CM. Yield exhibited a quadratic response to PD under both regimes; however, DF shifted the optimal PD upward (456–487 seeds m⁻²) compared with CM (377–378 seeds m⁻²) and sustained near-maximum yields over a broader PD range. DF improved population productivity by increasing productive stem percentage and grains per ear, resulting in greater grain number per m² (sink size). DF also strengthened source capacity during grain filling: post-anthesis dry matter production increased by 15.5–17.6% and strongly associated with yield (r² ≥ 0.819). Source–sink analysis suggested that DF was associated with more density treatments showing simultaneously high grain number and high post-anthesis dry matter accumulation, a pattern consistent with a broader high-yield density range. Enhanced N acquisition, especially after anthesis, may have contributed to this response. DF increased N nutrition index at anthesis and markedly increased post-anthesis N uptake by 47.7–49.5%, thereby raising total N uptake at maturity and grain N accumulation. DF improved fertilizer-N recovery efficiency and agronomic efficiency by 33.9–42.3% and 26.7–30.9%, respectively. Collectively, DF improved N uptake and source–sink coordination, enabling high yield and reduced yield penalties when planting density deviated from the optimum. Full article

Distributed recycling of high-density polyethylene (HDPE) into filament for use in material extrusion 3D printing has been proposed as part of a circular economy. There is a gap in the understanding of the potential for HDPE to release contaminants that are potentially hazardous to human health during reuse. Herein, HDPE from post-consumer packaging waste was sorted into food and non-food (NF) streams and virgin HDPE was taken as a benchmark material. All materials were extruded into filaments and recycled multiple times while monitoring emissions. In general, particle and organic chemical emissions decreased by 93 to 99% and 73 to 99%, respectively, with increased reprocessing cycle without appreciable decline in mechanical (Young’s modulus decreased by 5 to 16%), processability (melt flow index stable from 0.2 to 0.7 g/10 min for waste plastics), and thermal properties (crystallinity ranged from a 6% decrease to a 9% increase) of plastics. An exception was a sub-stream of NF plastic that had increased particle emissions (up to 3100%) with reprocessing cycle. Reductions in emissions during filament extrusion appeared to be more influenced by reprocessing cycle than by any specific process step (grinding, etc.). The progressive decline in emissions without appreciable loss of polymer integrity could be exploited to pre-condition HDPE to reduce potential hazardous emissions prior to extruding into filament. This work helps fill the knowledge gap on approaches to recycling plastics in distributed settings such as home-based businesses, which is critical for developing effective recommendations for controls to enable safe work practices such as the use of ventilation to minimize exposures. Full article

Additive engineering has become a critical strategy for optimizing the morphology and performance of bulk heterojunction (BHJ) organic solar cells (OSCs), while volatile solid additives have been widely employed to control nanoscale phase separation during film formation. Concerns regarding reproducibility, residual solvent effects, and long-term stability have stimulated increasing interest in non-volatile solid additives. In recent years, solid additive engineering has emerged as a promising approach for modulating molecular packing, regulating phase separation, enhancing charge transport, and improving device stability. However, a systematic analysis of its material design principles and performance impact remains limited. This review summarizes recent progress in solid additive engineering for OSCs, categorizing reported additives into non-volatile, volatile and nanomaterials. The effects of these additives on key photovoltaic parameters, including open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), and power conversion efficiency (PCE), are comparatively analyzed based on the reported data. Particular emphasis is placed on morphology and structural performance relationships and stability enhancement mechanisms. Finally, current challenges, including the lack of universal molecular design rules and limited mechanistic understanding of additive host interactions, are discussed, and future research directions are proposed. This review aims to provide a comprehensive perspective on the material-level role of solid additives and to guide the rational design of next-generation high-performance and stable organic solar cells. Full article

Niobium is a strategic critical mineral that supports emerging energy and high-end manufacturing. The geophysical parameters of carbonatite-alkaline rock-type niobium deposits constitute essential baseline data for regional geophysical exploration and prospecting target delineation. To clarify the geophysical response characteristics and exploration the significance of the Dagele niobium deposit in the Eastern Kunlun Region (western China). This study focuses on drill hole ZK3202. Samples from ore bodies, mineralized zones, and wall rocks of different lithologies were continuously measured. Combined with 1001.8 m of full-hole core digital logging data, statistical methods, including box plots, histograms, multi-parameter cross-plots, and correlation coefficient analysis, were applied to quantitatively investigate the physical property responses of lithologies such as calcite-biotite rock (ore body), calcite-bearing pyroxenite (mineralized zone) and amphibolite in the vertical profile. Lithological identification thresholds were established to divide the drill-hole into lithological and mineralized ore layers. The results show that the ore-bearing lithofacies exhibit a distinctive geophysical signature characterized by high density, strong magnetism, medium-low resistivity, high polarizability, and slightly elevated natural radioactivity, which clearly distinguishes them from surrounding from wall rocks. Based on five key parameters—density, magnetic susceptibility, resistivity, polarizability, and natural gamma—a lithological identification model for amphibolite and mineralized altered rock assemblages was established. This study also summarizes the multi-parameter coupling mechanism of ore-bearing lithofacies, which can effectively delineate favorable niobium-bearing horizons. This work fills a gap in the geophysical property characterization of carbonatite-alkaline complex-type niobium deposits in the Eastern Kunlun region and provides data support and regional reference for integrated gravity-magnetic-electrical-radioactive geophysical exploration, prospecting target delineation, and the exploration of similar niobium deposits in western China. Full article

Gas-filled discharge capillaries are widely used in the field of plasma-based particle accelerators, due to their compactness, cost-effectiveness and versatility for different applications. Technological improvement of such plasma sources is necessary to enable high energy gain acceleration at the meter scale, as required for next-generation particle colliders and light sources. Beam quality preservation within such an acceleration length involves accurate tuning of the plasma properties. In particular, precise tailoring of the plasma density distribution is required to control the emittance growth of particle bunches during the acceleration process. In this context, this paper presents a scalable and versatile approach for the design of meter-scale discharge capillaries, aimed at achieving fine tuning of the plasma density distribution, with the possibility of locally controlling the density profile by acting on the source geometry. Forty-centimeter-long capillaries are designed using numerical fluid dynamics simulations and tested in a dedicated plasma module. Different arrangements of the gas inlets are tested, with their number and diameter varied, to assess the effect of the capillary geometry on the plasma properties. Plasma density measurements show that a higher number of inlets with variable diameter along the plasma formation channel provides an enhancement in the homogeneity of the electron plasma density distribution. Longitudinal density plateaus are observed along most of the plasma channel length, with a center-to-end density uniformity of up to 80%. The experimental results highlight the proposed approach’s capability to modulate the longitudinal plasma density distribution by acting on the capillary geometry, thus providing uniform density profiles over the meter scale, as required for plasma-based acceleration experiments. Full article

To enhance the early-age properties of steel slag cement mortar and promote the resource utilization of metallurgical solid waste, in this study, nano-SiO₂ (KH-NS) was modified using a KH550 silane coupling agent. The hydration kinetics and microstructure evolution were systematically analyzed by means of a macroscopic performance test (setting time and compressive strength) and multi-scale microscopic characterization (characterized by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, Thermogravimetry-Differential Thermal Analysis, and isothermal calorimetry). The influence mechanism of its content on the early performance of the steel slag cement system was systematically studied. Research findings indicate that at a given dosage, increasing the proportion of KH-NS results in a shorter setting time for steel slag mortar. When the KH-NS dosage reaches 1.5%, the initial and final setting times of steel slag mortar decrease by 24.21% and 21.20%, respectively. The addition of KH-NS effectively enhances the compressive strength of mortar, with a particularly pronounced effect on early strength prior to 14 h of curing. At a KH-NS dosage of 1.5%, the onset of the accelerated phase of hydration heat release in steel slag cement mortar is advanced by 2.5 h. Mechanistic studies indicate that KH-NS accelerates cement hydration by promoting C₃S dissolution and C-S-H gel nucleation through interactions between surface silanol groups (Si-OH) and amino groups (-NH₂). Furthermore, KH-NS refines the pore structure via a micro-aggregate filling effect, reducing the number of harmful pores and improving the pore size distribution. KH-NS continuously consumes Ca(OH)₂ through pozzolanic reactions to generate C-S-H, with its reactivity increasing with higher dosage. Research confirms that KH-NS significantly enhances the early strength and density of steel slag mortar, providing both theoretical justification and technical support for developing low-carbon building materials based on solid waste with high dosage. Full article

Cu₂ZnSn(S,Se)₄ (CZTSSe) is a candidate thin-film photovoltaic material; however, its performance is restricted by innate defect-induced nonradiative recombination. Low-concentration Ge doping has been identified as an efficient way to mitigate these defects, but the selenization temperature remains an important process parameter that governs the structure and optoelectronic characteristics of CZTSSe absorbers. In the present work, low-concentration Ge-doped Cu₂ZnSn_0.95Ge_0.05S₄ (CZTGS) precursor films were synthesized through a green, n-butylammonium butyrate-based solution approach. The effects of the selenization temperature (530–570 °C) on the microstructure, composition, and photovoltaic performance of Cu₂ZnSn_0.95Ge_0.05(S,Se)₄ (CZTGSSe) films and devices were comprehensively investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectrometer (EDS), atomic force microscopy (AFM) were performed to comprehensively characterize the synthesized samples, and the results suggested that the selenization temperature dramatically altered the film grain growth, crystallinity, elemental retention and surface roughness. Specifically, the film that underwent selenization at 550 °C presented the best crystallinity, which was accompanied by large-scale even grains, efficient Ge⁴⁺ addition to the kesterite lattice and the lowest surface roughness. These better properties in terms of structure and composition resulted in the lowest carrier transport resistance (R_s = 8.6 Ω∙cm²), improved recombination resistance (R_j = 5.9 kΩ∙cm²), inhibited nonradiative recombination, and prolonged carrier lifetime (τ_EIS = 35.8 μs). Therefore, the resulting CZTGSSe thin-film solar cell had an 8.69% better power conversion efficiency (PCE), while its open-circuit voltage (V_OC) was 0.42 V, the fill factor (FF) was 55.51%, and the short-circuit current density (J_SC) was 37.71 mA·cm⁻². Our results elucidate the mechanism by which the selenization temperature regulates low-concentration Ge-doped kesterite devices and provide more insights into the optimization of processes for cost-effective, high-performance, and green thin-film solar cells. Full article

Material extrusion (MEX) additive manufacturing can produce material-dependent variations in dimensional fidelity, internal structure, and deposition stability, even under identical processing conditions. In this study, a comprehensive experimental investigation is conducted on MEX-printed specimens manufactured from a broad set of PLA-based composite materials to quantify these variations and assess their mutual interdependence. Dimensional behavior, internal structural characteristics, and process behavior were systematically investigated using complementary geometric, physical, and deposition-related descriptors. All properties were determined from replicated specimens to ensure statistical robustness, and the resulting datasets were examined using both conventional metrics and multivariate 3D correlation approaches. Compact PLA-based formulations exhibit consistent internal packing, characterized by relative density (RD) values of approximately 0.40–0.46, porosity (ϕ) levels around 55–60%, reduced (≤0.15%) density variability (CV), and small (−0.4–0.0%) volumetric deviations (ΔV). These features reflect stable extrusion and predictable dimensional response. In contrast, foamed, fiber-reinforced, and organic-filled composites display reduced internal packing (RD < 0.40), increased ϕ (>60%), elevated CV (0.27–0.58%), and systematically larger positive ΔV (up to +1.4%), indicating a higher sensitivity to process-induced heterogeneity. Multivariate correlations further reveal that volumetric dimensional distortion is jointly governed by internal packing efficiency and extrusion stability. Overall, the results demonstrate that dimensional accuracy in MEX of PLA-based composites arises from coupled structure–process interactions rather than isolated material or process parameters. The experimental framework proposed here provides quantitative guidance for material selection and process optimization aimed at enhancing geometric fidelity in composite filament fabrication. Full article

As a world-renowned tourist and gaming city, Macau’s jewelry industry has formed significant spatial clustering driven by the integration of the tourism and gaming industries. However, existing research has not thoroughly explored the coupling mechanism between the agglomeration of this high-value industry and tourism potential circulation characteristics. Meanwhile, the industry confronts practical challenges, including an unbalanced layout between high-end and local brands, intense competition in core areas, and distinct service coverage blind spots in non-core areas. To fill these research gaps, this study takes the Macau Special Administrative Region as the research scope, integrates POI kernel density estimation, Voronoi diagram analysis, and space syntax to construct a three-dimensional analytical framework encompassing agglomeration intensity, service scope, and tourism flow matching, and systematically investigates the spatial clustering pattern of jewelry stores and its coupling mechanism with tourism potential circulation. The study reveals the following findings: (1) Jewelry stores exhibit a dual-segment, four-core clustering pattern. Among these, 38 high-end brands are concentrated in casino complexes and their surrounding areas, 34 comprehensive brands are evenly distributed across core and residential areas, and 300 local brands are mainly scattered in residential areas of the Macau Peninsula. (2) The service scope of jewelry stores is negatively correlated with agglomeration density. The Voronoi diagram area in core areas is 62% smaller than that in non-core areas, accompanied by a high degree of overlap—35% for high-end brands—and intense competition. In contrast, non-core areas have coverage blind spots accounting for 18% of Macau’s total land area. (3) Under a 300 m walking radius, high-integration paths identified by space syntax demonstrate an 85% matching degree with tourist routes, and the four core areas form differentiated coupling types. This study is the first to quantify the differentiated coupling mechanism between multi-level jewelry brands and tourism potential circulation. It further improves the GIS analysis framework for the coupling between commercial agglomeration and tourist behavior. The revealed negative correlation between service scope and agglomeration density, and the adaptive principle between brand spatial layout and regional functional attributes, provide universal references for similar business formats in tourist cities, including cultural and creative retail and characteristic catering. In practice, this research optimizes the spatial layout of Macau’s jewelry industry and increases the coverage rate of service blind spots to over 85%. It also provides scientific support for tourism route planning and the coordinated development of tourism and commerce in high-density tourist destinations. Full article

As a key low-expansion material for high-end equipment such as aerospace and precision instruments, the surface quality of Invar alloy directly determines the operational performance of devices. To fill the research gap in the multi-parameter synergy and mechanism of Invar alloy laser polishing, this study performs polishing experiments on Invar alloy using a burst-mode femtosecond laser, with a repetition rate of 1 MHz and four sub-pulses per burst. The results indicate that energy density plays a dominant role in the polishing effect: with the increase in energy density, the surface roughness first decreases and then increases. A stable molten pool is formed under medium energy density (0.47–0.64 J/cm²), and under the optimal parameter conditions, the surface roughness is reduced to 394 ± 50 nm, representing a 52% reduction compared to the original surface (821 nm). Scanning speed and scanning pitch affect the polishing effect by synergistically regulating energy input: increasing scanning speed under high energy density can inhibit the rise in roughness, while a small scanning pitch can lower the threshold of optimal energy density. Amplitude spectrum analysis reveals that the medium-scale surface undulations are significantly improved after polishing. A four-layer Fully Connected Neural Network (FCNN) model is established to achieve high-precision prediction of polishing effects with a coefficient of determination R² = 0.92, which enables rapid prediction of unknown polishing parameter combinations and provides a new solution path for the optimization of polishing effects. This study clarifies the interaction mechanism between a burst-mode laser and Invar alloy, proposes an efficient ultra-precision polishing method for Invar alloy, and lays a theoretical foundation for its application in the field of high-end manufacturing. Full article

The market value of fragrant rice is largely defined by the presence and intensity of its aroma, which is primarily attributed to volatile compound 2-acetyl-1-pyrroline (2-AP). The biosynthesis of 2-AP is chiefly governed by recessive alleles of the badh2 gene. Nevertheless, 2-AP accumulation is also profoundly shaped by environmental factors and agronomic management. Field practices—such as balanced nitrogen and potassium fertilization, supplementation with trace elements, and application of plant growth regulators like methyl jasmonate—promote 2-AP synthesis by increasing precursor availability and enhancing the activity of key enzymes. Additionally, tillage systems, alternate wetting and drying irrigation, optimal planting density, and harvest timing significantly affect aroma quality. Abiotic stresses, including moderate drought, salinity, optimal temperatures around 25 °C, and low light during grain filling, can also stimulate 2-AP accumulation, often through shifts in proline metabolism and activation of stress-responsive pathways involving GABA and methylglyoxal. Despite the promise of these strategies, several challenges persist, such as the common trade-off between yield and aroma intensity, complex genotype-by-environment interactions, and incomplete elucidation of the molecular mechanisms involved. Moving forward, integrating multi-omics analyses with smart agriculture technologies will be essential to unravel the regulatory networks underlying aroma formation and to advance the breeding of high-yielding fragrant rice varieties with stable aroma traits under changing climate scenarios. Full article