Search Results (22,989)

Preparing a highly wear-resistant AlTiN coating on a powder metallurgy (PM) M42 high-speed steel substrate is a key strategy to enhance tool performance and meet the demands of efficient machining. This study adopted a process route comprising substrate preparation, heat treatment regulation, and arc-PVD deposition of AlTiN coatings to systematically investigate the influence of sintering temperature (1130, 1160, and 1190 °C) and austenitizing time (1150 °C for 0, 15, 60, and 120 min) on the microstructure and mechanical properties of the substrate, as well as on the tribological performance of the AlTiN coatings. The results indicate that elevating the sintering temperature promotes densification of the matrix, with Vickers hardness increasing from 366 HV to 462 HV and bending strength (σ) increasing from 1064 MPa to 1310 MPa. The predominant carbide phases identified are MC, M₂C, and M₆C. During austenitizing, microstructural changes consistent with a progressive transformation from M₂C to MC and M₆C carbides were indicated by SEM and XRD analyses. Precipitation strengthening was most evident after 60 min, with hardness reaching 868 HV. In contrast, bending strength (σ) exhibited a progressive decline with increasing austenitizing time, decreasing from 1310 MPa to 1015 MPa after 120 min, illustrating a clear trade-off between hardness and toughness. The wear behavior of the coating is governed synergistically by substrate hardness, bending strength (σ), coating–substrate interfacial adhesion strength (L_C), and carbide phase transformation. Elevated substrate hardness enhances anti-wear performance; bending strength influences crack propagation and spallation tendency; and L_C determines the efficiency of interfacial load transfer. The carbide phase evolution appears to modulate the coating’s wear behavior by regulating both the microstructure and mechanical properties of the substrate. Among the six sample conditions evaluated, the A3 sample (sintered at 1190 °C and austenitized for 120 min) exhibited the lowest wear rate (2.38 × 10⁻⁶ mm³·N⁻¹·m⁻¹), demonstrating superior wear resistance. These findings provide a reference for process optimization and rational design of M42/AlTiN composite coating systems. Full article

This study examines the effects of laser power (P), scanning speed (SS), and energy density (ED) on the microstructure and hardness of WC-reinforced Inconel 625 metallic matrix composite (MMC) coatings fabricated via a powder-based directed energy deposition (DED) process developed by Makino Asia Pte Ltd. Coating layers were evaluated for surface roughness (Sa), layer height (LH), porosity (Pr), dilution height (DH), dilution ratio (DR), and WC retention (WC%). Trends in the data reveal how process parameters influence deposition quality and microstructural evolution: higher P or lower SS increased melt pool depth, promoted WC dissolution, and coarsened microstructure, whereas lower P or higher SS preserved WC particles and minimized substrate dilution. Hardness variations in the Inconel 625 matrix were associated with dendrite size, solid-solution strengthening, dislocation density, and secondary carbide formation. These findings provide quantitative guidance for selecting DED parameters to produce crack-free WC-Inconel 625 MMC coatings with controlled microstructure and tailored mechanical properties. Full article

Background/Objectives: The presented study aimed to understand the relationship between knowledge, attitudes, and practices, as well as consumers’ preferences for the consumption of Spirulina-enriched fruit and vegetable juices. Methods: A survey about the consumers’ attitudes towards consumption of algae in general and especially Spirulina was conducted to better understand the target groups and marketing strategies for this novel non-alcoholic beverage product. Knowledge–Attitude–Practice (KAP) model in combination with structural equation modelling (SEM) was applied to test the hypothesised relationships between the variables. Additionally, consumers’ preference test was done using a seven-point hedonic scale and ranking of the six juice samples: plain sour cherry juice (SC1), sour cherry juice with 0.8% (SC2) and 1.6% (SC3) of blue Spirulina powder; plain tomato juice (T1), tomato juice with 0.8% (T2) and 1.6% (T3) of blue Spirulina powder. Results: The SEM results showed that there is a limited direct impact of knowledge on social motivation, while personal behaviour strongly predicts social motivation. Namely, perceived nutritional value and health benefits were shown to be the main factors for consumers’ willingness to drink Spirulina-enriched juice. Conclusions: The result of the consumer preference evaluation exposed that the juices containing sour cherry and Spirulina achieved better sensory acceptance and ranking than those containing tomato, pointing out the importance of the product matrix for achieving consumer acceptance. Full article

Background/Objectives: Cannabidiol (CBD) has emerged as a potential therapeutic agent for respiratory disorders, including asthma and chronic obstructive pulmonary disease. However, its clinical translation via pulmonary delivery is limited by poor aqueous solubility, chemical instability, and low local bioavailability. This study aimed to develop and optimize a sodium stearate (NaSt)-based spray-dried dry powder inhaler (DPI) formulation to enhance the aerosol performance, dissolution, and storage stability of CBD. Methods: CBD microparticles were prepared by spray drying using NaSt as the primary excipient. The feed preparation method, spray-drying parameters, and CBD:NaSt ratios were systematically optimized. The resulting powders were evaluated for aerodynamic properties using cascade impaction, dissolution behavior in simulated lung fluid, solid-state characteristics, and accelerated stability under stress conditions. Results: The optimized formulation, SD-4, a spray-dried CBD:NaSt formulation prepared at a 20:80 weight ratio using Process B, demonstrated excellent aerosolization performance, with a fine particle fraction (FPF) exceeding 50% and a mass median aerodynamic diameter (MMAD) of 5.08 ± 0.1 μm. Dissolution testing revealed more than a three-fold increase in drug release compared with raw CBD, attributed to amorphous dispersion within the NaSt matrix and surfactant-induced micellization. Accelerated stability studies confirmed improved retention of the amorphous state and drug content, while antioxidant incorporation further reduced oxidative degradation. Conclusions: The NaSt-based spray-dried formulation significantly improved aerosol deposition efficiency, dissolution rate, and physicochemical stability of CBD. This formulation strategy may provide a promising platform for pulmonary delivery of poorly water-soluble compounds. Full article

Laser-based Powder Bed Fusion (LPBF) enables the fabrication of complex metal components but often results in high porosity and microdefect densities, compromising fatigue performance despite acceptable static properties. Standard fatigue characterisation methods are time-consuming and costly and yield scattered results due to defect-induced brittleness and residual stresses. This study investigates the application of thermographic techniques as a rapid alternative for evaluating the intrinsic fatigue behaviour of tensile coupons fabricated by LPBF employing AISI 316L steel. By monitoring surface temperature during stepwise static monotone and fatigue loading, thermographic methods aim to detect early hints of heat dissipation associated with microdamage initiation. Approaches based on temperature harmonic analysis have been implemented, allowing near-real-time and full-field mapping of stress distribution and damage development. Results show that harmonic metrics correlate with the material state and effectively track the thermoelastic effect-induced temperature changes. Some evidence is found regarding the onset of intrinsic heat dissipation, which needs to be confirmed by more focused and extensive experimental tests. Full article

Soft magnetic composite materials have a low total loss and high magnetic conductivity and are highly desirable for high-frequency motors, semiconductors, and 5G communication technologies. However, these composites often contain a high-volume fraction of soft magnetic metallic powders and are difficult to process into complex shapes. Herein, iron-based amorphous powders were surface-modified with silane coupling agents (DTMS and KH570) and applied in 3D direct ink writing (DIW). The modified powders exhibit improved compatibility and dispersion in epoxy resin. The optimized 92.3 wt% FeSiB@3.35 wt% KH570/EP slurry shows favorable rheological properties and a dense interfacial microstructure. The printed composite achieves the best magnetic performance (M_s: 137.02 ± 1.2 emu/g, H_c: 6.63 ± 0.2 Oe) and stable permeability up to 1 GHz. The surface modification enhanced slurry fluidity, preventing nozzle blockage and increasing powder loading. Various shaped magnetic cores were successfully fabricated with excellent magnetic properties and printing quality. Our work paves a new way for realizing the high processibility of soft magnetic composites, which lays a foundation for a technique for the wide applications of these materials in various electronic devices. Full article

Driven by the demand for miniaturization, high capacitance, and enhanced reliability in high-performance multilayer ceramic capacitors (MLCCs), the continuous thinning of inner electrode layers imposes increasingly stringent requirements on the size, distribution, morphology, and dispersion of nano-nickel powders. We systematically investigate how functional additives regulate the nucleation, growth, and microstructural evolution of nano-nickel synthesized via hydrazine-driven liquid-phase reduction of nickel sulfate. The results demonstrate that the alkanolamine complexing agent (TAC) significantly refines the average particle size and morphology of the nano-nickel through coordination effects. Furthermore, inorganic sulfur salts (ISP), acting via surface adsorption to passivate growth sites and provide catalytic effects, enable a precise and continuous reduction in the average particle diameter from 330 nm down to 60 nm at a mere trace dosage of ~10⁻⁷ mol/L. Regarding dispersion optimization, highly dispersed face-centered cubic (FCC) nano-nickel was successfully prepared by introducing multidentate carboxylate (NNA). High-resolution transmission electron microscopy (HRTEM) was employed to unveil, for the first time, the crystallographic origin of the anomalous surface protrusions typically observed in conventional reaction systems. We confirmed that the family of $\left\{10\overline{1}0\right\}$ crystal planes within these regions, which exhibits interfacial angles of 58.7° and 58.3°, corresponds to a thermodynamically metastable hexagonal close-packed (HCP) nickel phase originating from atomic stacking faults induced by rapid growth kinetics. To address this microstructural defect, a thioether-based amino acid (TAA) was introduced. TAA effectively suppresses the anisotropic growth of the metastable HCP phase through the strong steric hindrance of its long side chains and its selective adsorption onto high-energy facets. Full article

The calculation for the local bearing capacity of stirrup-confined concrete is an important issue in structural design. Due to the coupling effects of multiple factors, there is no unified calculation method recognized by scholars. The improved backpropagation neural network model based on the particle swarm optimization algorithm (PSO-BPNN) is used in this research to conduct a systematic analysis. The results of 40 stirrup-confined concrete specimens from the tests conducted by ourselves and an additional 92 similar test data points from references were combined; the calculation efficiency and accuracy of the PSO-BPNN model were verified. Compared with the BPNN model, the training iterations of the PSO-BPNN model were reduced by 74.23% with the condition of same training effect. The mean squared error (MSE) is reduced by 33.9%, and the coefficient of determination (R²) is increased by 5.5% with the condition of the same number training iterations. In addition, compared with the calculation stability and accuracy of Random Forest Regression (RFR), Support Vector Regression (SVR), and Extreme Gradient Boosting (XGBoost) models, the PSO-BPNN model also shows better results. Within the applicable range of the codes, the average ratio of the predicted values to the calculated values for GB50010-2010, MC2020 and ACI318-25 are 1.988, 1.719, and 5.387, respectively. A higher evaluation for the contribution of stirrup is considered in the MC2020 code; the predicted values of some specimens are lower than the calculated values when A_cor/A_l is less than 1.35. The brittleness effect is not adequately considered: the predicted values of some specimens are also lower than the calculated values with the active powder concrete (RPC) is used. The sensitivity ranking of the model with coupling effect for parameters is A_l, A_b, f_c,k, s, d, d_cor, and f_y,k. It is slightly different from the sensitivity ranking obtained by analyzing individual parameters, but the calculation logic is consistent. The research results can provide a theoretical basis for practical engineering. Full article

Mineral powder–based bone grafts exhibit excellent osteoconductivity; however, their clinical efficacy is often compromised by insufficient early-stage tissue ingrowth, leading to particle aggregation and pocket formation within the defect site during the initial healing phase. Here, we report a cotton-type nanofiber-guided mineral graft designed to overcome this early integration failure by creating fibrous pathways for tissue ingress. Cotton-type polycaprolactone (PCL) nanofibers were fabricated via electrospinning using a pin-based collector engineered to induce strong inter-fiber repulsion, resulting in a highly expanded, three-dimensional cottony architecture. Tetracalcium phosphate (TTCP) and α-tricalcium phosphate (α-TCP) mineral particles were subsequently deposited onto the surface of the cottony nanofibers, forming a fibrous–mineral hybrid graft (c-NF@T/α-TCP) in which the nanofibers act as a transient, functionally defined tissue-guiding framework during the early healing phase. The cottony nanofiber network effectively prevented mineral particle aggregation and generated continuous pathways within the graft, facilitating early tissue infiltration and vascular ingress during the first week after implantation. In vivo evaluation in a bone defect model demonstrated that c-NF@T/α-TCP significantly reduced tissue pocket formation at early time points and promoted subsequent bone regeneration compared to mineral powder-only grafts. This study highlights the critical importance of early-stage structural guidance in mineral-based bone grafts and introduces cotton-type nanofiber–guided pathway engineering as a simple yet effective strategy to unlock the regenerative potential of conventional inorganic bone substitutes. Full article

This study investigates the fabrication, characterization, and computational analysis of a Ti6Al4V porous scaffold for bone tissue engineering (BTE). The main objective is to address the stress-shielding effect caused by the mismatch in the mechanical properties between the scaffold and surrounding bone. An octet-truss architecture was considered to design a highly porous scaffold (with 80.5% porosity) and fabricated using selective laser melting (SLM). The scaffold was then treated with post-processing chemical etching in oxalic acid to remove surface defects and tailor topography. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that etching effectively removed adhered unmelted powder particles and created a distinct micro-textured strut surface (with increased roughness) that is conducive to osseointegration. The etching process also uniformly thinned down the struts and resulted in 10% mass loss. A compression test gave the scaffold’s compliance-corrected elastic moduli of 4.54 ± 0.18 GPa (pre-etching) and 3.53 ± 0.06 GPa (post-etching). These values closely match with the stiffness of human trabecular bone reported in the literature. The experimental modulus results were validated with a finite element model that predicted 4.188 GPa, which agrees well with the experiment. Furthermore, computational fluid dynamic simulations evaluated a permeability of 8 × 10^–9 m², consistent with transport in bone-like structures. Full article

Background: Inhaled therapy is the mainstay of asthma management, yet many patients are prescribed pressurized metered-dose inhalers (pMDIs) with valved holding chambers (VHCs) based on a presumed low inspiratory capacity, often without objective measurement. The USE-DPI study aimed to determine how many of these patients can generate sufficient peak inspiratory flow (PIF) to use a dry powder inhaler (DPI). Methods: This multicenter, observational, cross-sectional study included 346 patients with asthma treated with pMDI and VHC. PIF was measured using the In-Check Dial at two resistance settings (R2 and R4). The primary outcome was the proportion of patients achieving PIF ≥ 30 L/min. Results: Almost all patients reached the 30 L/min threshold (99.4% at R2 and 98.7% at R4). Using a higher threshold of 60 L/min (R2), 76.1% met this criterion. Lower PIF (<60 L/min) was associated with older age, reduced lung function (FEV1 ≤ 80% predicted), and poorer asthma control. No significant variables were associated with failure to reach 30 L/min. Conclusions: Most patients using pMDI with VHC can generate sufficient inspiratory flow for medium- to high-resistance DPIs. Objective PIF assessment may help guide inhaler selection, although its clinical impact requires further study. Full article

This study examined the life characteristics, fecundity, and innate immune response of fairy shrimp (Branchinella thailandensis Sanoamuang, Saengphan and Murugan, 2002) cultivated on Chlorella vulgaris, biofloc, dried powder Spirulina sp., and a formulated feed. These feeds were selected to compare traditional live feed (Chlorella vulgaris), microbial-based feed (biofloc), and alternative dry feed in order to identify a sustainable feeding strategy for fairy shrimp culture. The lifespans of male and female fairy shrimp reared on the biofloc diet were the longest at 44 ± 6.00 and 44.33 ± 4.67 days, respectively. Fairy shrimp reared on the biofloc diet demonstrated significantly enhanced growth, with lengths of 25.66 ± 1.75 mm in males and 27.60 ± 2.08 mm in females. The highest fecundity was also observed in the biofloc treatment, with 25 ± 6.65 broods per female, an average of 229.57 ± 2.08 eggs per brood, and a total of 5726.33 ± 1518.11 eggs per female over their lifespan. Fairy shrimp fed with Chlorella vulgaris, biofloc, and Spirulina sp. showed significantly high levels of superoxide dismutase (SOD) and lysozyme activities compared to those fed on a formulated feed, while malondialdehyde (MDA) levels, a marker of oxidative stress, were lower in these three groups. Results suggested that biofloc was a viable feed option for B. thailandensis, which positively influenced growth, lifespan, and fecundity while enhancing the innate immune function. Full article

Growing concerns over food waste and the increasing demand for gluten-free products highlight the need for sustainable food innovations. This study investigated the valorization of tomato processing by-products as functional ingredients in gluten-free crackers. Tomato by-products were dehydrated, milled into powder, and incorporated into cracker formulations at 10%, 20%, and 30% (w/w). The crackers were evaluated for bioactive compound content (lycopene, total carotenoids, and total phenolics), antioxidant activity (DPPH radical scavenging), and sensory acceptability using a 5-point hedonic test with 50 consumers. Increasing the level of tomato by-product incorporation significantly enhanced the nutritional profile of the crackers. Lycopene content increased from 0.65 mg/100 g in the control to 9.43 mg/100 g at 30% enrichment, while total phenolic content increased from 52.60 to 154.76 mg GAE/100 g. Sensory evaluation indicated that the 10% enrichment achieved the highest overall acceptability score, whereas higher enrichment levels resulted in slightly reduced taste preference. These findings demonstrate that tomato by-products can be effectively used to improve the nutritional quality of gluten-free crackers while maintaining acceptable sensory properties at moderate enrichment levels, supporting the sustainable valorization of tomato processing residues. Full article

The effect of microstructural evolution on mechanical behavior of carbon/carbon composites after heat treatment has been investigated. Two kinds of samples, heat-treated at 2300 °C and 2700 °C, were used in the current study. As the heat treatment temperature is 2700 °C, the pyrolytic carbon acquires a higher orientation via carbon atomic layer rearrangement, accompanied by microstructural evolution such as self-healing of concentric ring cracks, narrowing of the fiber/matrix interface and bridging between adjacent fibers. This microstructural evolution results in a significant decline in the mechanical properties of the composites: compressive strength, flexural strength, and shear strength decreased by approximately 60%, 68%, and 71%, respectively, while the corresponding fracture strains increased by 52%, 25%, and 19%, respectively, indicating an improvement in pseudoplasticity. 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