Search Results (14,757)

Long-term intensive cultivation has caused soil fertility decline and structural degradation in the Songnen Plain, thereby constraining maize root development and yield formation. As a fundamental conservation tillage practice, straw return enhances soil function by incorporating exogenous organic matter and regulating root-shoot physiological processes. However, the mechanism underlying yield improvement through root–photosynthesis–nitrogen synergy remains insufficiently understood. A field experiment was conducted to assess the effects of conventional tillage (CT), straw incorporation (SI), straw mulching (SM), and deep straw incorporation (DF) on maize physiological traits and yield. Compared with CT, DF markedly enhanced root morphology and physiology, increasing the root length, surface area, volume, and root-shoot ratio by 16.46%, 23.87%, 26.64%, and 51.34%, respectively. The root bleeding intensity increased by 23.63%, whereas amino acid and nitrate contents in the bleeding sap increased by 29.20% and 65.93%, respectively, indicating improved root nutrient transport capacity. The enhanced root system positively influenced shoot photosynthesis by increasing the chlorophyll SPAD value by 16.05%, net photosynthetic rate (P_n) by 11.28%, and the activities of RuBP, PEP, nitrate reductase (NR), and glutamine synthetase (GS) by 10.59%, 24.36%, 29.94%, and 12.47%, respectively. These synergistic improvements significantly promoted post-anthesis biomass accumulation and yield formation. DF increased nitrogen and dry matter accumulation at the R3 stage by 26.61% and 15.67%, respectively, and resulted in an average yield increase of 8.34%, which was primarily due to an 11.96% increase in 100-grain weight. Although SI and SM also improved certain physiological indices, their effects were weaker than those of DF. RF analysis identified sap nitrate content (RNO), bleeding intensity (RBI), root length (RL), and root volume (RV) as key yield determinants. PLS-SEM further revealed that straw return enhanced root morphology and bleeding traits (path coefficients: 0.96 and 0.82), which subsequently improved leaf photosynthetic traits (path coefficients: 0.52 and 0.39) and biomass accumulation (path coefficient: 0.71). Collectively, these improvements promoted post-anthesis nitrogen accumulation and dry matter partitioning into grains. These findings elucidated the physiological mechanism by which deep straw incorporation increased maize yield through root system optimization, providing a theoretical basis for conservation tillage optimization in the thin-layer Mollisol region of the Songnen Plain. Full article

Laser Powder Bed Fusion (LPBF) technology represents one of the most promising additive manufacturing methods, enabling the production of components with high geometric complexity and a wide range of industrial and biomedical applications. In this study, the influence of both standard and high-productivity process parameters on the microstructure, porosity, surface roughness, and hardness of three commonly used materials, stainless steel 316L, aluminum alloy AlSi10Mg, and titanium alloy Ti6Al4V, was analyzed. The investigations were carried out on samples fabricated using the EOS M290 system, and their characterization was performed with scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), porosity analysis by point counting, Vickers hardness measurements, and optical profilometry. The obtained results revealed significant differences depending on the alloy and the applied parameters. For stainless steel 316L, the high-productivity variant led to grain refinement and stronger crystallographic orientation, albeit at the expense of increased porosity (0.11% vs. 0.05% for the standard variant). In the case of AlSi10Mg alloy, high-productivity parameters enabled a substantial reduction in porosity (from 0.82% to 0.27%) accompanied by an increase in hardness (from 115 HV1 to 122 HV1), highlighting their particular suitability for engineering applications. For the Ti6Al4V alloy, a decrease in porosity (from 0.17% to 0.07%) was observed; however, the increase in mechanical anisotropy resulting from a stronger texture may limit its application in cases requiring isotropic material behavior. The presented research confirms that optimization of LPBF parameters must be strictly tailored to the specific alloy and intended application, ranging from industrial components to biomedical implants. The results provide a foundation for further studies on the relationship between microstructure and functional properties, as well as for the development of hybrid strategies and predictive models of the LPBF process. Full article

In this study, aiming to develop novel biocomposites that offer competitive properties while retaining their renewable and biodegradable characteristics, a biodegradable polymer matrix (Mater-Bi^® HF51L2) was reinforced with natural particles extracted from the culm and leaf of Cymbopogon flexuosus (lemongrass). Particles (<500 µm) were incorporated at 10 and 20 wt.% via twin-screw extrusion followed by compression moulding. Morphological analysis via SEM revealed distinct structural differences between culm- and leaf-derived particles, with the latter exhibiting smoother surfaces, higher density, and better dispersion in the matrix, resulting in lower void content. Quasi-static mechanical tests showed increased stiffness with filler content, particularly for leaf-based composites. This material, at 20 wt.% filler loadings, enhanced the tensile and flexural moduli of the neat Mater-Bi approximately three and two times, respectively, a result attributed to enhanced interfacial adhesion. Rheological measurements (rotational and capillary) indicated significant increases in complex viscosity, particularly for leaf-filled systems, confirming restricted polymer chain mobility and good matrix–filler interaction. Dynamic mechanical thermal tests (DMTA) results showed an increased storage modulus and a shift in glass transition temperature (T_g) for all biocomposites in comparison to Mater-Bi matrix. Specifically, the neat matrix had a T_g of −28 °C, which increased to −24 °C and −18 °C for the 20 wt.% culm-reinforced and leaf-reinforced biocomposites, respectively. Overall, the leaf-derived particles demonstrated superior reinforcing potential, effectively improving the mechanical, rheological, and thermal properties of Mater-Bi-based biocomposites. Full article

Bacterial cellulose (BC) is a type of biomass composed entirely of cellulose. This characteristic favors the presence of a multitude of active sites, which facilitate the exchange of heavy metals present in polluting effluents. Upon contact with water contaminated with metals such as chromium, arsenic, and lead, among others, this biomass offers a potential solution to the environmental problem of industrial pollutants in water. This is particularly pertinent given the well-documented harmful effects of heavy metals in aquatic ecosystems. In this context, the objective is to determine the impact of temperature on Cr (IV) adsorption using bacterial cellulose biomass as an adsorbent, under different temperature scenarios, similar to the conditions of discharge of contaminated effluents into rivers, lagoons, and wetlands. In this study, the biomass was previously characterized through FTIR and SEM images, and isothermal models were subsequently evaluated along with batch adsorption kinetics. The findings demonstrate that bacterial cellulose biomass has great potential for Cr (VI) removal at various temperatures, with an adsorption capacity of 140 mg/g at high temperatures and a reduction of up to 125 mg/g at low temperatures. The findings of this study constitute a valuable contribution to decision-making when considering the expansion of these treatment processes, facilitating this task by offering a comparative analysis of effluent discharge conditions in relation to various scenarios involving contaminated liquid temperatures. The use of this biomaterial in an environmental sustainability initiative focused on water resource conservation is a very promising prospect. Full article

The Ti6Al4V alloy is considered the most beneficial of the titanium alloys for use in biomedical applications. However, it corrodes when exposed to various biocompatible fluids. This investigation aims to evaluate the corrosion inhibition performance of the Ti6Al4V in a saline solution (SS) using thiocolchicoside (TCC) drug as an environmentally acceptable corrosion inhibitor. The corrosion assessments were conducted using potentiodynamic polarization curves (PPCs), open-circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) methodologies, supplemented by scanning electron microscopy (SEM), energy-dispersive X-ray (EDS) analysis, atomic force microscopy (AFM), and contact angle (CA) measurements. The outcomes indicated that the inhibitory efficacy improved with higher TCC concentrations (achieving 92.40% at 200 mg/L of TCC) and diminished with an increase in solution temperature. TCC’s physical adsorption onto the surface of the Ti6A14V, which adheres to the Langmuir adsorption isotherm, explains its mitigating power. The TCC acts as a mixed-type inhibitor. The adsorption and inhibitory impact of TCC were examined at various temperatures using PPC and EIS. When TCC is present, the corrosion’s apparent activation energy is higher (35.79 kJ mol⁻¹) than when it is absent (14.46 kJ mol⁻¹). In addition, the correlation between the structural properties of thiocolchicoside (TCC) and its corrosion inhibition performance was systematically analyzed. Density Functional Theory (DFT) calculations were utilized to characterize the adsorption mechanism, supported by Natural Bond Orbital (NBO) analysis and Molecular Dynamics (MD) simulations. The combined computational and electrochemical findings confirm that TCC provides effective and enhanced corrosion protection for the Ti6Al4V alloy in a saline environment. These characteristics provide compelling evidence for the suitability of these pharmaceutical compounds as promising corrosion inhibitors. Full article

The research investigates the mediating influence of Green Human Resource Management (GHRM) practices—including environmentally focused recruitment, training, and performance management—on the relationship between green leadership and employees’ green advocacy within Saudi Arabia’s hospitality and tourism industry. Data were gathered through a structured questionnaire administered to supervisors and managers working in five-star hotels, producing 544 valid responses for analysis. The conceptual framework was examined using Structural Equation Modeling (SEM) with the WarpPLS 0.7 software to rigorously assess both the measurement validity and structural associations. The analysis demonstrated that green leadership exerts a positive and significant impact on GHRM practices as well as on employees’ willingness to advocate for environmentally responsible behaviors. Furthermore, GHRM initiatives were found to strengthen employees’ pro-environmental engagement and serve as a partial mediating channel between green leadership and green advocacy. Overall, the findings highlight that institutionalizing sustainable HRM approaches is a fundamental route through which leadership enhances environmental accountability and promotes the long-term economic viability of the hospitality sector. The study concludes by underscoring its theoretical and managerial implications, emphasizing how leadership-guided sustainability actions can foster an organizational culture grounded in ecological responsibility. Full article

Graphite, with its layered structure and weak van der Waals bonding between graphene nano layers, exhibits excellent self-lubricating properties. Natural graphite, characterized by high crystallinity, and artificial graphite, with relatively low crystallinity, exhibit distinct friction behaviors and structural differences, which significantly influence the performance of graphite–resin composites as solid lubricants. This study investigates the effects of natural/artificial graphite ratios and hydrophobic silane coupling treatment on the oil impregnation behavior, friction coefficient, wear stability, and microstructural changes in graphite–resin composites. Under a vertical load of 88,260 N and surface pressure of 50 MPa, the impregnated graphite–resin composites demonstrated low friction coefficients and stable wear behavior. SEM analysis revealed well-preserved microstructures, and Raman spectroscopy confirmed the formation of stable lubrication films through the I_D/I_G ratio, indicating graphene exfoliation. The results indicate that natural graphite provides dense structures and stable friction, while artificial graphite enhances oil impregnation but leads to unstable friction behavior. Full article

Profile control is widely employed to improve oil recovery in fractured-vuggy carbonate reservoirs. However, the limitation of current experimental evaluation methods restricts their practical guidance for field applications. In this study, urea-formaldehyde resin gel (URG) is studied using SEM, rheological analysis, FTIR, and Raman spectroscopy. Typical structural models of fractured-vuggy reservoirs are fabricated by 3D printing technology. The distribution patterns of the URG in different fractured-vuggy models are also investigated by using online NMR analysis and core slice characterization. Results show that URG exhibits a kind of 3D mesh structure with a size of 10 μm after gelation at 140 °C. The storage modulus (G′) and loss modulus (G″) of the URG gel are 387.51 Pa and 131.48 Pa, respectively. Chemical composition analysis reveals that URG is mainly composed of amide groups and sulfonate groups, showing excellent thermal stability and salt tolerance. Furthermore, after injecting URG into three types of typical models, URG displays a longitudinally decreasing distribution pattern from the injection side to the outlet side, accompanied by transverse accumulation phenomenon along the fracture walls in the slab fracture model. In the fractured-vuggy model, the gel shows continuous longitudinal distribution and uniform transverse distribution characteristics. In the beaded-vug train model, the gel’s distribution morphology gradually transforms from a “pipeline-filling” pattern at the injection side to a “conduit-dominant” pattern toward the outlet side, with a stepped distribution in the transverse direction. The breakthrough pressures during subsequent water flooding are as follows: beaded-vug train model (11.6 MPa) > fractured-vuggy model (8.1 MPa) > slab fracture model (5.9 MPa). Field application results show that the water cut is reduced from 85% to 30%, with a total incremental oil production of 2416 tons. This study conducts experimental investigations on the distribution patterns of URG in simulated fractured-vuggy models, thereby establishing a novel technical evaluation method for profile control in actual fractured-vuggy carbonate reservoirs. Full article

Composites in which finely dispersed particles of the metallic phase are uniformly distributed over the surface of expanded graphite can be used as magnetic sorbents for crude oil and petroleum products, as well as a basis for creating screens that protect against electromagnetic radiation. The literature describes various approaches to obtaining such materials, but from a technological point of view, the most promising is the method in which the formation of a metal-containing phase on the surface of expanded graphite is directly combined with its expansion. For this purpose, graphite intercalation compounds with chlorides of metals of the iron triad (GIC-MCl_x) were obtained: GIC-FeCl₃ of I-VII stages, GIC-CoCl₂ of I/II stage and GIC-NiCl₂ of II/III stage, which were treated with liquid NH₃ or CH₃NH₂ in order to obtain an occlusive complex, which, due to the presence of a large amount of bound RNH₂, would be capable of effective thermal expansion during heating in an inert atmosphere with the formation of low-density expanded graphite, and the presence of reducing properties in ammonia and methylamine would lead to the reduction of the metal from chloride. The structure of GIC-MCl_x and GIC-MCl_x treated by NH₃ and CH₃NH₂ was investigated by XRD analysis and Mossbauer spectroscopy. The composition of the metal-containing phase in expanded graphite/metal composite was determined by XRD analysis and its quantity by the gravimetric method. The distribution of metals particles is investigated by SEM, TEM and EDX methods. Expanded graphite/metal composites are characterized by the high saturation magnetization (up to ≈ 50 emu/g) at a bulk density of 4–6 g/L. Full article

Background/Objectives: Children with autism spectrum disorder (ASD) frequently experience poor compliance with oral medication due to bitterness, unpleasant taste, and unsuitable dosage forms such as large tablets or capsules. Risperidone, a widely prescribed antipsychotic for managing ASD symptoms, is particularly challenging in this regard. The present study aimed to develop a novel sucrose-based microfiber drug delivery system to improve the palatability, acceptance, and bioavailability of risperidone in pediatric patients with ASD. Methods: Risperidone was incorporated into sucrose microfibers using centrifugal spinning technology. Fiber morphology was characterized by scanning electron microscopy (SEM). Drug loading (DL), encapsulation efficiency (EE%), and disintegration time were measured. In vitro drug release and cytotoxicity assays were performed using human foreskin fibroblast cells (HFF-1). An in vivo palatability and preference study was conducted in male BALB/c mice to evaluate the acceptability of the formulation compared with a commercial risperidone oral solution. Results: SEM analysis revealed smooth, bead-free, non-porous fibers with uniform morphology and size distribution. The formulation showed a rapid disintegration time of ~3 s, DL of 30 ± 5 µg/mg, and EE% of 60 ± 10%. Approximately 50% of risperidone was released within 15 min. Cytotoxicity testing confirmed that concentrations ≤ 125 µg/mL maintained high cell metabolic activity, indicating biocompatibility. In vivo, the microfiber solution demonstrated a strong preference (93%) compared with the commercial oral solution (30%). Conclusions: Risperidone-loaded sucrose microfibers represent a promising fast-dissolving oral delivery system for children with ASD. This child-friendly formulation improves palatability and compliance while maintaining safety and drug release performance. Full article

Background/Objectives: Acanthamoeba keratitis (AK) is a rare but sight-threatening corneal infection, often associated with contact lens wear and resistant to conventional therapies. Preventive strategies capable of reducing Acanthamoeba adhesion to corneal epithelium may represent an important tool for infection control. This study aimed to evaluate the amebicidal and preventive activity of CORNEIAL MED eye drops against Acanthamoeba castellanii adhesion and early adhesion layer on human corneal epithelium (HCE). Methods: Reconstructed HCE models were exposed to A. castellanii under four experimental conditions: negative control (HCE only), positive control (HCE + A. castellanii), co-incubation with CORNEIAL MED and A. castellanii (Study 1), and treatment with CORNEIAL MED after initial A. castellanii adhesion (Study 2). Adherent amoebae were quantified using EDTA detachment and Neubauer chamber counting. The early adhesion layer was characterized by scanning electron microscopy (SEM). Statistical analysis considered p < 0.05 as significant. Results: In Study 1, simultaneous application of CORNEIAL MED with A. castellanii reduced amoeba adhesion by 33.0 ± 11% compared with controls (p = 0.0529). In Study 2, when the product was applied 3 h after amoeba inoculation, adhesion was significantly reduced by 51.9 ± 6.5% (p < 0.05). SEM confirmed a decrease in amoebic colonization and biofilm density in treated samples. Conclusions: CORNEIAL MED demonstrated a measurable inhibitory effect on A. castellanii adhesion to HCE, particularly when applied after initial pathogen contact. These findings suggest a potential preventive role of CORNEIAL MED in reducing AK risk, although further in vivo studies are warranted. Full article

The construction industry’s growth is causing a surge in CO₂ emissions, driven by increased demand for concrete and other building materials. There is a growing demand for more sustainable building materials, including alkali-activated materials. This study investigates the impact of varying ratios of Na₂SiO₃ and NaOH on the mechanical properties and microstructure of metakaolin (MKW) and ceramic brick waste (CBW) based geopolymer binder. Geopolymer binder precursors were made of three main CBW/MKW ratios: 100/0%wt. (C100), 50/50%wt. (C50M50), and 0/100%wt. (M100). Alkaline activator solutions had three different Na₂SiO₃/NaOH ratios: 0.5, 1.0, and 2.0. The investigation into the geopolymer binder mechanical properties was conducted using a range of analytical methods, including compressive strength, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The findings of the study indicate that the Na₂SiO₃/NaOH ratio alone is inadequate for evaluating geopolymer mechanical properties when different AS/P ratios are employed, given its influence on other parameters, such as the W/S ratio and the total Na₂O content. CBW-based geopolymer binders demonstrate limited capacity to attain substantial compressive strengths because they contain high amounts of unreacted CBW particles, as shown by XRD analysis. The incorporation of MKW precursor resulted in enhanced reactivity and intensified geopolymerization reaction. After the evaluation of all essential ratios, the most favorable Na₂SiO₃/NaOH ratio is 1.0. This determination was based on the highest strengths observed in designs that contained ≥50% of MKW precursor, attributed to predominance of goosecreekite and N-A-S-H gels, as evidenced by XRD and FT-IR analysis. Full article

In this paper, we demonstrate a simplified method for fabricating ohmic contacts on 4H-SiC substrates using pulsed UV laser surface modification followed by application of a silver-based conductive adhesive. Even a small number of laser passes significantly improved the contact interface, while ten or more repetitions produced linear I–V characteristics with low voltage drops. SEM analysis revealed surface ablation and an expanded effective area of the contact. Raman spectroscopy proved that laser processing leads to surface amorphization of the SiC sample. DFT simulations showed that the amorphous SiC layer is a material with no band gap, explaining the elimination of the Schottky barrier. Our approach enables the manufacturing of reliable, low-resistive contacts without high-temperature annealing and offers a practical route for rapid SiC device prototyping. Full article

This paper presents a rare example of the conservation of a piece of marine oval-shaped tableware, commonly known as a ‘cloche’, made of nickel silver with silver electroplating that was recovered in 2006 from the 19th-century Patris paddle-wheel shipwreck in Greece. Our study found that the cloche is made of two components of differing compositions of nickel-silver alloy, also known as German silver: a forged body and a cast handle, joined by lead soldering. The body also has an impressed decorative stamp bearing the ‘Greek Steamship’ signature in Greek. The condition assessment found the object was covered in thick concretion formations and suffered galvanic corrosion, along with dealloying, resulting in redeposition of copper. The conservation treatment carried out in 2007 is detailed along with diagnostic examination using microscopic analysis, radiographic imaging, and chemical analysis of the corrosion and metal, using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and portable X-ray fluorescence (pXRF). The conservation of the object involved mechanical and chemical methods (formic acid 5–10% v/v, stabilisation treatment with sodium sesquicarbonate 1% w/v), including spot electrolysis, and the object was coated with 15% w/v Paraloid B72 in acetone. Since its conservation, the object has been on display in the Industrial Museum of Hermoupolis in Syros. In 2025, the object was inspected for its coated surface as well as to carry out pXRF again with a more advanced system to better understand the alloy composition of the object. These results are presented here for this unique object. Full article

This research investigated the feasibility of producing strontium-doped nanocrystalline hydroxyapatite (SrHAp) through an environmentally benign synthesis approach and evaluated the antimicrobial activity of the resulting material. The synthesized nanomaterial was subjected to comprehensive characterization. The antimicrobial efficacy of SrHAp was tested against Gram-positive and Gram-negative bacterial strains. X-ray diffraction (XRD) analysis in combination with Fourier-transform infrared (FT-IR) spectroscopy confirmed the successful formation of pure monocrystalline SrHAp. The scanning electron microscopy (SEM) examination revealed two predominant morphological structures: nanorods and prismatic configurations of the SrHAp. Transmission electron microscopy (TEM) demonstrated that the rod-like SrHAp nanocrystals aggregate into elongated grain structures with a size of about 25 nm × 10 nm. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis confirmed the presence and quantification of the concentrations of calcium, strontium, and phosphorus, while confirming the expected calcium–phosphorus ratio characteristic of hydroxyapatite. The study established that the positive surface charge of the material, with a point of zero charge near pH 10, is essential for its antimicrobial efficiency. These results suggest that SrHAp nanomaterials hold promise for biomedical applications, particularly as antimicrobial coatings for implants and scaffolds for bone tissue, where the prevention of infection is critical. Overall, despite its selective and material quantity-dependent antimicrobial efficacy, environmentally friendly synthesized SrHAp can be successfully applied as an effective controller of targeted microbial contamination, especially of Gram-positive bacterial species S. aureus, L. monocytogenes, S. Enteritidis, and A. baumanii. Full article