Search Results (1,858)

Tungsten–diamond metal matrix composites (MMCs) fabricated via L-PBF show potential for applications in nuclear facility shielding, heat sinks, precision cutting/grinding tools, and aerospace hot-end components. In this paper, tungsten (W), diamond (D), and diamond with Ni coating (D-Ni) powders are used to fabricate W+D and W+(D-Ni) composites by L-PBF technology. The results show that at the interface of the W+D sample, the W powder melts while the D powder remains in a solid state during L-PBF processing, and W and C elements gradually diffuse into each other. Due to the high cooling rate of L-PBF processing, the C phase forms a diamond-like carbon (DLC) phase with an amorphous structure, and the W phase becomes a supersaturated solid solution of the C element. At the interface of the W+(D-Ni) sample, the diffusion capacity of Ni and W elements in the solid state is weaker than in the molten state. C and W elements diffuse into the Ni melt, forming a rich Ni area of the DLC phase, while Ni and W elements diffuse into the solid D powder, forming a lean Ni area of the DLC phase. In the rich Ni area of the DLC phase, Ni segregation leads to the precipitation of nanocrystals (several hundred nanometers), whereas in the lean Ni area of the DLC phase, the diffusion capacity of Ni and W elements in the solid D powder is limited, resulting in nanocrystalline sizes of only about tens of nanometers. During W dendrite growth, the addition of the Ni coating and the expelling of the C phenomenon leads to W grain refinement at the interface, which reduces the number and length of cracks in the W+(D-Ni) sample. This paper contributes to the theoretical development and engineering applications of tungsten–diamond MMCs fabricated by L-PBF. Full article

It has been demonstrated that the traditional hydrometallurgical method is still economically viable in several industrial applications such as Bayer, Boix, Platsol, Sherrit-Gordon, and so on. The conventional extraction technique of valuable metals from their ores using an aqua medium has several challenges. The following can be listed for the illustration of this: (1) Inorganic acids used during the leaching process have been proven to be non-environmentally friendly and ready to lead to non-selective processes in general, except in rare cases used in alkaline environments. (2) Special linings are required in the reactors used due to the corrosive impact of acids such as HCl and H₂SO_4, especially when leaching at high temperatures, rendering all processes costly. (3) Practically, using inorganic acids while leaching samples containing amorphous silicate phases leads to gel formation. Solvometallurgy overcomes these challenges by substituting the aqueous phase for other polar solvents, such as polar molecular organic or ionic solvents. The advantage of this substitution lies in the ability to manipulate metal ion distribution using solvents with varying solvation properties. This review examines the potential of solvometallurgical processes (solvoleaching) over conventional hydrometallurgy as viable alternatives for metal extraction from sulfide ores. It highlights the key distinctions between hydrometallurgy and solvometallurgy while emphasizing the potential economic and environmental advantages solvometallurgy offers. Full article

Treating poultry manure with calcium compounds is the primary technique for inactivating toxic pathogens such as bacteria, fungi, or viruses and decreasing the risk of biological contaminant release into the environment. On the other hand, the preferable method for reducing its volume is incineration with the aim of obtaining highly concentrated fertilizer. This paper presents the optimization of the biological deactivation of fresh poultry manure using calcium hydroxide via central composite design and response surface methodology. The results revealed that the optimum parameters required to decrease the number of E. coli bacteria to below the acceptable level (1000 CFU/g) were 5.0 wt% Ca(OH)₂ at 22 °C and an exposure time of 209 h. A regression analysis showed a good fit of the approximated parameters to the experimental data (R² = 98%, R_adj.² = 97%). Additionally, laboratory tests involving ash samples obtained from the incineration of poultry manure with the addition of 5 wt% calcium hydroxide (T = 500 °C, t = 5 h) intended as a fertilizer for degraded soils were performed. The analysis revealed that the content of pure manure ash in the sample incinerated with Ca(OH)₂ was approximately 47.5%. An X-ray diffraction analysis of the ash sample revealed that the main crystalline component was calcite (67.5 wt% CaCO₃), the phases containing phosphorus were apatite (3 wt%) and hydroxyapatite (3 wt%), whereas the source of the bioavailable form of phosphorus was the amorphous phase (15.5 wt%). An analysis of the ash extracts in a 2% citric acid solution revealed that the phosphorus concentration (287 mg/L) was two times lower than that of potassium (661 mg/L). The best results of phytotoxicity tests with Sinapis alba were obtained for soils containing no more than 1.0 wt% ash with calcium hydroxide. Full article

Vegetal sources are a continuous research field and different types of extracts have been obtained over time. The most challenging part is compounding them in a pharmaceutical product. This study aimed to integrate a mixture (EX) of four extracts (SE-Sophorae flos, GE-Ginkgo bilobae folium, ME-Meliloti herba, CE-Calendulae flos) in formulations with polymers (polyhydroxybutyrate, polylactic-co-glycolic acid) and their physicochemical profiling. The resulting samples consist of particle suspensions, which were subjected to Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy analysis. When compared to single-extract formulations spectra, they revealed band changes, depending on the complex interactions. Using X-ray Diffractometry, the partially crystalline phase was highlighted for EX-PLGA, while the others were amorphous. Moreover, Atomic Force Microscopy pointed out the nanoscale particles and the topography of the samples, and the outstanding roughness belonging to EX-PHB-PLGA. A 30 min period of immersion was enough for the formulations to spread on the surface of the compression stockings material (CS) and after drying, it became a polymeric film. TGA analysis was performed, which evaluated the impregnated content: 5.9% CS-EX-PHB, 6.4% CS-EX-PLGA, and 7.5% CS-EX-PHB-PLGA. In conclusion, the extract’s phytochemicals and the interactions established with the polymers or with the other extracts from the mixture have a significant impact on the physicochemical properties of the obtained formulations, which are particularly important in pharmaceutical product development. Full article

Thin films of bismuth(III) sulfide (Bi₂S₃) on fluorine doped tin oxide (FTO) coated glass slides were successfully formed by the chemical bath deposition (CBD) method. In this work, a new sulfur precursor L-cysteine was used instead of the typical sulfur precursors, such as urea, thiosulfate, or thioacetamide, used for the formation of the Bi₂S₃ films by the CBD method. The synthesized Bi₂S₃ thin film on the FTO substrate was subjected to characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and UV–Visible spectroscopy analysis. An X-ray diffraction analysis showed that, initially, Bi₂S₃ films of an amorphous structure with elemental sulfur impurities were formed on the FTO surface. During the annealing of the samples, amorphous Bi₂S₃ was transformed into its crystalline phase with an average crystallite size of about 22.06 nm. The EDS studies confirmed that some of the sulfur that was not part of the Bi₂S₃ was removed from the films during annealing. The influence of the morphology of Bi₂S₃ films on their optical properties was confirmed by studies in the UV-visible range. Full article

Silicon-doped tetrahedral amorphous carbon (ta-C:Si) coatings are promising materials for achieving ultralow friction in water-lubricated environments, attributed to the formation of Si(OH)_x-based tribofilms. However, the deposition process via filtered cathodic vacuum arc (FCVA) often introduces large particles into the film, increasing surface roughness and causing accelerated wear during the initial sliding phase, despite the high hardness of the coating. In this study, ball-on-disk tribological tests were performed to investigate the wear behavior of ta-C:Si coatings under water lubrication. Friction coefficients, wear volume, and surface roughness were analyzed over various sliding durations. The Archard wear equation and the plasticity index were used to analyze wear and contact behavior. The friction coefficient decreased from 0.14 to 0.04 within the initial 100 m section, and the surface roughness of ta-C:Si decreased sharply from 0.35 μm to 0.01 μm based on the Rpk parameter during 10 h. Following this period, the plasticity index decreased from an initial value of 1.1 to below 0.6, transitioning to a fully elastic contact stage, marking the onset of steady-state wear after 10 h. These results indicate that the reduction in surface roughness plays a crucial role in stabilizing wear behavior and provide insights into optimizing the long-term performance of ta-C:Si coatings in aqueous environments. Full article

Arsenic-containing acidic wastewater from nonferrous heavy smelting industry is a dangerous source of arsenic pollution due to its complex composition, high acidity, and strong toxicity. In this study, an environment-friendly strategy was proposed, in which highly stable scorodite was synthesized in acidic wastewater. The effects of initial pH, Fe/As molar ratio, and oxidation-reduction potential (ORP) on the morphology, particle size, phase composition, and leaching stability of scorodite were systematically investigated. The results demonstrate a distinct morphological evolution with increasing pH. The products were transitioned from bone-shaped to rice grain-shaped, and then turned to bipyramidal polyhedral-shaped and amorphous aggregates. When the Fe/As molar ratio was increased, the scorodite crystallization quickly formed well-defined particles (the size was 15–20 μm). Higher ORP values led to progressively irregular morphologies, reduced particle sizes, and ultimately formed amorphous ferric arsenate. The large-grained scorodite with regular morphology and high leaching stability from high-arsenic solutions (25 g/L) was produced under optimal conditions (initial pH 1.5, Fe/As 1.5, ORP 385 mV). These findings provide critical technical support for arsenic solidification from waste liquids under atmospheric pressure conditions. Full article

A TC4 alloy was joined with Ti-Zr-Cu-Ni amorphous filler by vacuum brazing. The paper further explored how different brazing temperatures with a 20 min holding time, or varying holding times at a brazing temperature of 900 °C, impact the interface width, microstructure, composition distribution, microhardness, shear strength, and fracture surface of the brazed joints. The findings indicated that as the brazing temperature increased, the interface width became wider. Moreover, as the brazing temperature continued to rise, both the size of the Widmanstätten structure and the amount of the (Ti, Zr)₂(Cu, Ni) brittle phase increased continuously, leading to the joint exhibiting harder and more brittle properties. As the temperature rose from 860 °C to 900 °C, the microhardness went up from 462.8 HV_0.1 to 482.6 HV_0.1. But when the temperature continued to increase (920 °C, 940 °C), the microhardness started to decrease, until it reached 392.6 HV_0.1 at a holding time of 20 min. As the brazing temperature increased, the width of the joint interface expanded, and the shear strength continued to rise. When the brazing temperature rose to 940 °C, the shear strength increased to 223.9 MPa under a holding time of 20 min. With the prolongation of the holding time (from 10 min to 30 min), the Widmanstätten structure at the joint interface continuously grew towards the center. Additionally, the (Ti, Zr)₂(Cu, Ni) phase and eutectic structure were separated by the Widmanstätten structure. The microhardness and shear strength reached their maximum values at 900 °C, and the shear strength was measured at 137.6 MPa. Full article

Poly-ether ether ketone (PEEK) is a high-performance thermoplastic known for its excellent mechanical properties, making it relevant for aerospace and medical applications. Additive manufacturing (AM) represents a critical step towards integrating PEEK into these sectors, particularly for complex geometries and custom parts. However, the mechanical properties achieved through AM have not yet reached those obtained via conventional techniques. Recent studies have sought to optimize the printing parameters to bridge this gap, but their findings remain inconsistent and difficult to generalize—suggesting a strong dependence on the experimental conditions. This is partly due to the Fused Filament Fabrication of PEEK being an emerging technology, with many studies relying on in-house built printers. Moreover, the underlying microstructural mechanisms governing its performance have rarely been explored in depth. In this work, we establish clear processing–structure–property relationships by integrating a rigorous DoE approach with comprehensive microstructural characterization. Our results highlight the dominant role of the processing environment near the glass transition temperature in promoting chain mobility, enhancing the amorphous phase ordering, and improving the mechanical performance: crystallinity alone does not fully explain the mechanical behavior of additively manufactured PEEK. Further, higher nozzle temperatures lower the porosity and increase the filament bonding, while faster printing speeds reduce the crystallinity and increase the porosity, negatively affecting the mechanical integrity. The results of this study are generalizable to any FFF printer of PEEK. Other materials or printing technologies are out of the scope of this work. Full article

Nanopowders of hydroxyapatite (HA) and Fe-substituted hydroxyapatite (HAFe) were synthesized by wet precipitation on either MCM-41 (a synthetic, mesoporous aluminosilicate material) or an aluminum-containing MCM-41 (AlMCM) support. According to X-ray diffraction data, all of the synthesized materials are composite powders consisting of amorphous silicate and an HA phase with low crystallinity. The presence of aluminum and iron in the structure of the powders resulted in further amorphization. The obtained samples showed high specific surface areas (SSAs), ranging from 162.3 to 186.6 m²/g for MCM-41-HA and from 112.6 to 127.2 m²/g for AlMCM-HA. The hysteresis loops were found to be of type H3, indicating the formation of slit-like pores in the intercrystalline space, as confirmed by transmission electron microscopy, which revealed the presence of lamellar and flake-like particles. Catalytic activity tests showed that the conversion of dibenzothiophene depended on the iron concentration in the material and the acidity of the support. To further improve the catalytic activity of the materials, they were impregnated with molybdenum compounds. Active molybdenum peroxo complexes formed under these conditions enabled 100% conversion of dibenzothiophene. To our knowledge, this is the first study on the influence of MCM-41-HA- or AlMCM-HA-based materials on dibenzothiophene conversion via oxidative desulfurization using hydrogen peroxide as an oxidant. Full article

With humans living longer and the median age of the population increasing, there is an ever-increasing demand for better biomedical implants. Titanium implants have a long history of successful use, but their naturally forming amorphous oxide surfaces are not ideal to promote bone growth. Therefore, titanium surfaces are often modified to improve bioactivity through electrochemical processes such as anodization which can crystallize the oxide into more bioactive titanium oxide phases, form hierarchical micro- and nano-scale roughness profiles, and incorporate beneficial bone chemistry into the oxide layer to improve interactions with bone cells. We have recently developed three innovative anodization electrolytes based on combinations of citrus fruit juices and commercially available calcium compounds. Anodization in these electrolytes produced citrus-based oxides exhibiting surface Ca/P ratios within the range of human bone, unique cauliflower-like hierarchical micro- and nano-scale surface roughness profiles, and the formation of titanate compounds which have been shown to be precursors for subsequent apatite formation. Thus, our titanate-containing citrus-based oxides show much promise for improving future osseointegration. Full article

Background/Objectives: Proteolysis-targeting chimeras (PROTACs) have shown significant potential in the treatment of intractable diseases. However, their clinical applications are limited by poor water solubility and permeability. In this study, the cyclodextrin inclusion method was employed for the first time to prepare the PROTAC-CD complex with the aim of improving the dissolution of a PROTAC drug (LC001). Methods: Initially, sulfobutyl ether-β-cyclodextrin (SBE-β-CD) was selected to improve the solubility of LC001. The polymer TPGS was screened based on the phase solubility method to enhance the efficiency of complexation and solubilization capacity, and its ratio with SBE-β-CD was optimized. The ternary complex was prepared by lyophilization with an SBE-β-CD/TPGS molar ratio of 1:0.03. Differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy results confirmed the formation of an amorphous complex. Fourier-transform infrared and molecular docking simulations indicated the formation of hydrogen bond interactions between components. Results: The results showed that the ternary complexes significantly improved the dissolution rate and release amount of LC001 in PBS (pH 6.8) and were unaffected by changes in gastric pH compared to the binary complexes and physical mixtures. The lack of crystal structure in the lyophilized particles and the formation of nano aggregates in solution may be the reasons for the improved dissolution of the ternary complex. Conclusions: In conclusion, the addition of TPGS to the LC001-SBE-β-CD binary system has a synergistic effect on improving the solubility and dissolution of LC001. This ternary complex is a promising formulation for enhancing the dissolution of LC001. Full article

Polyimide (PI) and polyamide 6 (PA6) films are treated under exposure times of 0.5 s and 1.0 s, and energy levels of 1.5, 2.0, and 2.3 mJ/pulse. PI exhibits the most substantial improvement in wettability and adhesion-related properties compared to PA6 and other studied polar polymers. The threshold level for stable surface modification is reduced, achieving a minimum water contact angle of 45°. The stability is markedly enhanced, with aged PI surfaces showing a 40% relative increase in adhesion work compared to untreated samples. The oxygen content on the PI surface reaches 22 at. %, surpassing the maximum of 18 at. % O observed for PA6. The surface roughness of PI increases by approximately a factor of 2, while PA6 shows an average increase of only 25%, attributed to higher ablation rates in the amorphous phase compared to the crystalline phase. The degree of surface modification achieved with [1.0 s; 1.5 mJ] treatment parameters is comparable to that with [0.5 s; 2.0 mJ], demonstrating that higher discharge energy can effectively shorten the required exposure time. This plasma treatment, even at very short exposure times, enables significant enhancement of the surface properties of PI, typically characterized by high chemical stability. Full article

Nowadays, some amorphous and microcrystalline solid-state electrolytes (SSEs) with dual anions have attained high ionic conductivity and good compatibility with electrodes in all-solid-state lithium-ion batteries (ASSLIBs). In this work, crystalline SSEs of series A (Li_1+xTaO_1+xCl_4−x, −0.70 ≤ x ≤ 0.50) and B (LiTaO_2+yCl_2−2y, −1.22 ≤ y ≤ 0), having great application potential well over ambient temperatures, were prepared at 260–460 °C for 2–10 h using Li₂O, TaCl₅, and LiTaO₃ as the raw materials. The three-phase coexisting samples attained high σ values ranging from 5.20 to 7.35 mS cm⁻¹, which are among the reported high values of amorphous co-essential SSEs and other alloplasmatic crystalline ones. It is attributed to the synergistic effect of the polyanion trans-[O₂Cl₄] and cis-[O₄Cl₂] octahedra framework. Full article

In this study, microwave-assisted extraction (MAE) was performed to recover antioxidant hemp seed oil (HSO) with the purpose of developing polybutylene succinate (PBS)/HSO-based films for active packaging to improve food shelf-life. It was found that MAE achieved comparable yields, structural characteristics, and antioxidant activity to Soxhlet extraction, but in significantly less time (2.5 min vs. 6 h). PBS-based films with 0.5 and 1 wt% HSO were prepared by compression molding. Morphological investigation of the PBS-HSO films highlighted uniform oil droplet dispersion and good compatibility. HSO reduced PBS crystallinity but did not affect the α-form of PBS. Thermal analysis showed reductions in T_m and T_c, whereas T_g remained unchanged at −17 °C. PBS containing 1 wt% HSO exhibited a 42% decrease in Young’s modulus, 47% reduction in elongation at break, and 47% decrease in tensile strength due to the plasticizing effect of the oil and, which reduced the intermolecular forces and facilitated polymer chain disentanglement, in agreement with the FTIR analysis, which showed a distinct broadening of the carbonyl stretching region associated with the amorphous phase (1720–1730 cm⁻¹) in the PBS-HSO films compared to neat PBS. Migration tests showed that the films are unsuitable for fatty foods but safe for aqueous, acidic, and alcoholic foods. Full article