Search Results (675)

Due to the unique microstructure and mechanical heterogeneity of austenitic stainless steel made via wire arc additive manufacturing (WAAM), its machinability differs significantly from that of rolled material. Accordingly, this study systematically investigates the influence of milling strategies on key process responses (cutting forces, surface roughness, vibration displacement, and temperature) to reveal the mechanisms of machining parameters during the milling of WAAM-fabricated austenitic stainless steel. The material used in this study is ER321 austenitic stainless steel. During deposition, the fusion zone cools more slowly than the transition zone; consequently, the fusion zone exhibits a hardness approximately 20 HV_0.1 lower than that of the transition zone. Surface roughness is primarily reduced by decreasing the primary feed per tooth. However, when the primary feed per tooth is small, ploughing is induced, which not only increases surface roughness by 25% but also causes abnormal increases in temperature and vibration displacement. Nevertheless, ploughing has little effect on the total milling force, and the feed per tooth shows a positive correlation with the total milling force. Tool run-out and an increase in the uncut chip thickness lead to a positive correlation between the radial depth of cut and the key process responses. Moreover, ploughing also occurs when the radial depth of cut is small. The axial depth of cut has almost no effect on the machining process. Moreover, a small-diameter mill leads to severe ploughing, and at a high table feed, climb milling leads to cutter offset. Full article

This study investigated the combined influence of hydrothermal treatment and particle size on the techno-functional properties of defatted coconut residue (DCR) to optimize its use as a hydrocolloid fat replacer. A 3 × 2 factorial design evaluated boiling and autoclaving treatments in combination with coarse and fine milling. Fine particle fractions (boiling-fine [BF] and autoclaved-fine [AF]) were identified as optimal, exhibiting peak water-holding capacity (WHC) (10.95 g/g) and oil-holding capacity (4.57 g/g) due to maximized surface area and thermal unblocking of capillary networks. When incorporated into cookies, all DCR formulations qualified as “reduced-fat” (30% reduction) and “high-fiber” (6 g/100 g) products. Crucially, the extreme WHC of fine fractions induced severe water competition within the dough, leading to a direct inverse correlation with quality, characterized by a restricted spread ratio (6.9) and increased hardness (27 N). Furthermore, thermal leaching of Maillard precursors suppressed excessive browning, improving cookie color. While the BF fraction provided the best functional balance, future research should optimize dough moisture to mitigate the impact of high fiber hydration on texture. These findings demonstrate DCR’s potential for agro-food valorization and improved human health. Full article

Accurate characterization of ore grindability is essential for optimizing mill throughput, reducing energy consumption, and predicting mill performance under varying ore conditions. However, the standard Bond work index (BWI) test remains time-consuming, costly, and requires a large amount of sample. This study evaluates the effectiveness of several rapid, low-cost alternatives, Leeb rebound hardness (LRH), Cerchar abrasivity Index (CAI), portable X-ray fluorescence (pXRF), and hyperspectral imaging (HSI), as proxies for grindability in gold-bearing ores. Sixty-two hand-size rock samples collected from two adjacent Canadian open-pit mines were analyzed using these techniques and subsequently grouped into ten ore groups for BWI testing. LRH and CAI effectively differentiated moderate (<15 kWh/t) from hard (>15 kWh/t) grindability classes, while geochemical features and HSI-based mineralogical attributes also showed strong predictive capability. HSI, in particular, provided non-destructive, spatially continuous data that are advantageous for complex geology and large-scale operational deployment. A conceptual workflow integrating HSI with complementary field measurements is proposed to support comminution planning and optimization, enabling more responsive and timely decision-making. While BWI testing remains necessary for circuit design, the results highlight the value of combining rapid proxy measurements with advanced analytics to enhance geometallurgical modelling, reduce operational risk, and improve overall mine-to-mill performance. Full article

In this study, B₄C nanoparticles were incorporated into AA2024, one of the aluminum alloys with superior mechanical and wear properties, with the aim of further enhancing its mechanical, tribological, and corrosion performance. The nanocomposites were produced using mechanical milling followed by powder metallurgy techniques. The effects of nano-sized B₄C additions on powder characteristics, microstructure, and physical, mechanical, tribological, and corrosion properties were systematically investigated through microhardness, density, SEM, XRD, bulk hardness, wear, and corrosion tests. B₄C was added at weight fractions of 0–2 wt.%, and all samples were mechanically milled for 8 h. The results revealed a gradual reduction in powder particle size and a corresponding increase in particle microhardness with increasing B₄C content. The sample reinforced with 2 wt.% nano-B₄C exhibited an approximately 80% increase in hardness and around a 55% improvement in tensile strength compared to the unreinforced alloy. Wear resistance was significantly enhanced, showing up to an 8-fold improvement under a 5 N load and a 6-fold improvement under a 25 N load. Furthermore, corrosion resistance nearly doubled with the addition of B₄C nanoparticles. Full article

The ball mill is a critical size reduction equipment in industries such as mining and metallurgy. However, the sustainable reliability modeling of the entire system is challenging due to its complex service conditions. This paper presents a systematic framework for the reliability analysis of ball mills based on Stress–Strength Interference Theory (SSIT). Based on a reliability block diagram (RBD), this study establishes a system-level reliability model for the ball mill. Within this framework, the cylinder model is developed using the energy conservation principle between impact energy and strain energy; the gear model comprehensively considers both contact and bending fatigue failure modes; and the bolt model is constructed through mechanical analysis in conjunction with Hooke’s law. In the case study, a laboratory-scale mill (Φ5.5 × 2.6 m shell, effective grinding chamber: 5.3 m inner diameter × 2.376 m length) operating at 14 RPM under dry grinding conditions is analyzed. The reliability of individual components and the entire system is computed using Monte Carlo simulation. The results indicate that the overall system reliability increases when one of the following three conditions is met: the surface hardness of the gear is higher and the tangential force is lower; the impact velocity on the cylinder is lower and the impacted area is larger; or the tensile force on the bolt is reduced. Full article

Semi-autogenous (SAG) milling represents one of the most energy-intensive and variable stages of copper mineral processing. Traditional deterministic models often fail to capture the nonlinear dependencies and uncertainty inherent in industrial operations such as granulometry, solids percentage in the feeding or hardness. This work develops and validates a stochastic model based on Discrete Bayesian networks (BNs) to represent the causal relationships governing SAG Production and SAG Power under uncertainty or partial knowledge of explanatory variables. Discretization is adopted for methodological reasons as well as for operational relevance, since SAG plant decisions are typically made using threshold-based categories. Using operational data from a Chilean mining operation, the model fitted integrates expert-guided structure learning (Hill-Climbing with BDeu/BIC scores) and Bayesian parameter estimation with Dirichlet priors. Although validation indicators show high predictive performance (R² ≈ 0.85—0.90, RMSE < 0.5 bin, and micro-AUC ≈ 0.98), the primary purpose of the BN is not exact regression but explainable causal inference and probabilistic scenario evaluation. Sensitivity analysis identified water feed and solids percentage as key drivers of throughput (SAG Production), while rotational speed and pressure governed SAG Power behavior. The BN framework effectively balances accuracy and interpretability, offering an explainable probabilistic representation of SAG dynamics. These results demonstrate the potential of stochastic modeling to enhance process control and support uncertainty-aware decision making. Full article

This study aimed to evaluate the efficacy of a palm oil-free structured lipid (SL) as a lipid base in sandwich-type cookie fillings. SL was enzymatically interesterified from a blend of soybean oil, high-oleic peanut oil, and crambe hard fat (34:34:32). Four fillings (30% fat) were prepared using either SL or commercial shortening (CS), with processing by mixer (F1, F2) or ball mill (F3, F4). Commercial sandwich cookies were included as a reference Standard. SL exhibited an improved lipid profile, containing up to 14% less saturated fatty acids, higher levels of monounsaturated (34.5%), and increased long-chain fatty acids (~18% C22:0). Physicochemical analyses were conducted over a storage period of 180 days, including evaluations of texture, particle distribution, color, water activity, oil loss, and oxidative stability. Among the formulations, F4 demonstrated the highest firmness (at ~121.1 N) and the smallest D₅₀ (~80 µm). However, it also exhibited lower oxidative stability (induction period: ~6.75 to 14.6 h) compared to CS-based fillings (~36 to 42.5 h), along with a higher oil loss (≥4.7%). Sensory of F4 yielded an overall acceptance index ≥ 70%, though it received lower scores for waxiness. Overall, the SL showed promising potential as a structuring fat in the fillings. Full article

Polyurethane (PU) is widely recognized for its efficient oil sorption properties. However, this capacity is highly dependent on its intrinsic chemical composition and morphological structure, which can be altered by mechanical or chemical treatments commonly applied before using it as a sorbent. In this study, we present a comprehensive investigation of the oil sorption behavior of both soft and rigid PU foams, and their blade-milled ground (BMG) counterparts obtained by mechanical treatment of several recycled PU-based products, including seats, mattresses, side panels of cars, packaging components, and insulating panels of refrigerators and freezers. We found that blade milling the soft PU foams leads to a significant reduction in oil sorption capacity proportional to the extent of grinding. Pristine soft PU foams and BMG-PUs with intermediate particle size (−250 μm–1 mm) exhibited the highest oil uptake (20–30 g/g), whereas the finest fraction (5 μm–250 μm) showed a lower capacity (3–7 g/g). In contrast, rigid PU foams showed consistently low oil sorption (~5 g/g), with negligible differences between the original and ground materials. At the macroscopic level, optical and morphological analyses revealed the collapse of the 3D porous network and a reduction in surface area. On the microscopic scale, spectroscopic, structural, and thermal analyses confirmed phase separation and rearrangement of hard and soft segmented domains within the polymer matrix, suggesting a different mechanism for oil sorption in BMG-PU. Despite reduced performance compared to pristine foams, BMG-PU powders, especially those with intermediate dimensions and originating from soft PU foams, present a viable, low-cost, and sustainable alternative for oil sorption applications, including oil spill remediation, while offering an effective strategy for effective recycling of PU foam wastes. Full article

To promote domestic wheat production in South Korea, four functional colored wheat varieties with varying amylose contents: Ariheuk (AH), Arijinheuk (AJ), Ariheukchal (AC), and Sintong (ST), were developed. This study examined their bread-making performance using whole wheat flour (WWF) milled under different conditions with an ultra-centrifugal mill (sieve openings: 0.5 and 1.0 mm; rotation speeds: 6000 and 14,000 rpm). Four flour samples per variety (FL, FH, CL, CH) were prepared. The median particle size (d50) varied among varieties, with harder kernels (AC, AH) producing larger particles than softer ones (AJ, ST). Smaller sieve openings increased the water and sodium carbonate solvent retention capacity, whereas higher rotation speeds reduced them, indicating less damaged starch. Sodium dodecyl sulfate sedimentation volume was higher in AC and AH, suggesting stronger gluten. Bread made from the group F WWF had higher volume and lower firmness, with AH-FH producing the best bread quality. Total phenolic and anthocyanin content and antioxidant activity were slightly higher in the group F, but markedly lower in the ST. Bread crusts showed increased phenolic and antioxidant activity but decreased anthocyanin content due to heat. Overall, kernel hardness, milling conditions, and amylose content strongly influenced purple WWF quality and bread performance, highlighting the need to optimize milling and formulation strategies. Full article

The growing use of 3D-printed dental restorations has created a need to understand how the mechanical behaviour of definitive 3D-printed resin composites compares with milled counterparts. This study compared the mechanical properties of 3D-printed and milled definitive crowns and examined the factors affecting these properties. The 3D-printed materials (Permanent Crown Resin: PCR, VarseoSmile Crown Plus: VCP, and Crowntec: CT) and milled blocks (Brilliant Crios: BC, Shofu Block HC: HC, and Grandio Blocs: Gr) were tested. Filler content was evaluated using the ash method (n = 3), and flexural strength (FS) and flexural modulus (E_f) were assessed using a three-point bending test (n = 10). Martens hardness (HM), indentation modulus, and Vickers hardness were determined using the Martens indentation test (n = 24). Vickers hardness was also measured with the Vickers indenter tester (n = 24). Statistical analysis investigated differences between materials and methods, and correlations between filler weight and mechanical properties (α = 0.05). FS of milled blocks, Gr (244.5 MPa), BC (225.5 MPa), and HC (155 MPa), were higher than that of the 3D-printed resin composites: PCR (143.6 MPa), CT (140.9 MPa), and VCP (128 MPa). Measured mechanical properties of the milled blocks were significantly higher than those of the 3D-printed materials (p < 0.001). HM of the 3D-printed materials was similar (≈217 N/mm²), while HM of the milled blocks ranged from 434.7 to 858.4 N/mm². The 3D-printed materials showed comparable properties; however, milled blocks differed significantly (p < 0.05). Filler content was strongly associated with FS and HM. Within the limitations of this study, the milled resin composites showed markedly higher strength and hardness, while 3D-printed materials may be suitable for low-to-moderate load clinical scenarios. Further studies to evaluate the long-term performance of the 3D-printed resin composites are recommended. Full article

This work investigates the influence of spark plasma sintering (SPS) parameters on the microstructure and mechanical properties of consolidated aluminum powders processed by high-energy ball milling under an air atmosphere. Sintering was performed under vacuum at various temperatures ranging from 550 °C to 625 °C and under pressures between 50 and 100 MPa. The particle size, crystallite size, and microstructure of the powders and the consolidated pellets were analyzed using laser granulometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Archimedes’ density measurements. Mechanical properties were evaluated via Vickers microhardness, nanoindentation, and tribological testing. For comparison, unmilled aluminum powders were also consolidated and characterized. After 46 h of milling, the aluminum crystallite size was reduced from 74 nm to 68 nm. The sample’s density increased with higher sintering temperature and pressure. The aluminum sintered at 600 °C and 100 MPa after 46 h of milling exhibited the highest microhardness (187.5 HV). Nanoindentation tests were conducted to characterize different microstructural regions formed after SPS, revealing two distinct zones: one hard and one soft. The tribology results revealed that the SPS-consolidated samples of milled powders exhibited a reduction of 50% in specific wear rate and a reduction of 20% in the coefficient of friction compared to the SPS-sintered samples of unmilled powders. Full article

Avocado processing generates seed by-products rich in dietary fiber that can be upcycled into functional ingredients. This study modified and characterized avocado seed flour via extrusion and enzyme-assisted wet-milling, as well as evaluated its use in wheat bread. The flour was fractionated, and fraction 2 (F2) was selected based on techno-functional performance; it was tested in its non-extruded (NEF2) and extruded (EF2) forms. Breads were prepared by replacing 5% of wheat flour with NEF2 and EF2 (NEB and EB, respectively). Compared with NEF2, EF2 had an 81% higher water absorption index (WAI) and an 18% higher oil absorption index (OAI). Extrusion reduced antioxidant activity ~1.6-fold, consistent with an ~85% decrease in acetogenin content, indicating thermo-mechanical degradation of bioactives linked to bitterness. Analyses were conducted in triplicate (p < 0.05). By day 3, crumb hardness increased (EB: 9.65 N; NEB: 6.04 N; control: 5.49 N). In a test with 106 consumers, aroma scores improved for NEB (8.00, IQR 7.00–8.00) and EB (7.00, IQR 5.00–8.00) versus the control (6.00, IQR 4.00–7.00), while overall acceptability, texture, color, and appearance did not differ. These results support EF2 as a functional upcycled ingredient that enhances hydration and aroma, reduces bitterness, and maintains consumer acceptance, aligning with circular economy and clean-label goals. Full article

Durum wheat (Triticum durum) is one of the main raw materials in the food industry, used primarily in the production of pasta. During milling, semolina and flour are obtained with different size distributions, and different compositional and functional characteristics, which influence processes such as gelatinization, retrogradation and the final texture of the products. Understanding these changes is essential for optimizing the technological quality and shelf life of processed foods. The aim was to evaluate how particle size, composition, temperature, and treatment time affect gelatinization, retrogradation, and gel texture. Samples included common wheat flour (control), durum wheat semolina, durum wheat flour, and re-milled semolina (<180 μm). Hydrothermal tests were conducted at 95 °C with varying holding times, and at 140 °C with extended cooling to observe retrogradation. Composition and particle size were found to determine rheological behavior. Semolina showed higher retrogradation and produced firmer gels, while durum wheat flour, with higher protein and ash content, showed atypical profiles and less consistent gels. Increased temperature and time enhanced breakdown and reduced final viscosity, indicating starch thermal degradation. A correlation was observed between final viscosity and gel hardness. This study provides information useful for optimizing the milling, cooking, and development of durum wheat-based products with improved texture and shelf life. Full article

Game meats are particularly prone to oxidation and microbial spoilage due to their specific characteristics and the procedures required to obtain them. Various sustainable bioactive molecules derived from food industry by-products, such as olive mill wastewater, have the potential to enhance the stability and safety of game meats. The use of different levels of polyphenolic extracts from olive mill vegetation water, encapsulated through a freeze-drying process, was tested on wild boar meat patties as an antioxidant and antimicrobial. Two separate trials were performed. Trial 1 was carried out by adding different concentrations of polyphenolic extract (0, 1, and 2%) during the production of wild boar patties, and trial 2 by adding 1.5% salt and adding or not adding 2% polyphenolic extract. The first trial revealed antioxidant effects on the raw patties during storage time, both on colour (increasing in saturation index) and thiobarbituric acid-reactive substances (0.306, 0.268, and 0.254 mg MDA/kg after 5 days of storage in the control with 1% and 2% polyphenolic extract groups, respectively). Oxidation was also reduced during cold storage of cooked patties. Trial 1 also revealed a dose-dependent antimicrobial effect, mainly on Enterobacteriaceae and Pseudomonas spp. Trial 2 confirmed that salt plus extract addition had an overall higher antimicrobial effect than when singularly added, but with a moderate increase in the hardness of the products. Full article

In this study, medium- and high-entropy carbide systems with compositions WC-TiC-TaC-HfC and WC-TiC-TaC-HfC-ZrC were successfully synthesized via a combination of mechanical activation (using high-energy ball milling, HEBM) and spark plasma sintering (SPS) at 1900 °C. Investigation of the SPS consolidation kinetics revealed that both systems undergo single-stage active densification via a solid-state sintering mechanism within the temperature range of 1316–1825 °C. The introduction of ZrC into the five-component system led to a 22% decrease in the maximum shrinkage rate (from 0.9 to 0.7 mm·min⁻¹), which is attributed to the manifestation of a sluggish diffusion effect, characteristic of high-entropy systems. X-ray diffraction analysis of the consolidated samples confirmed the formation of predominantly single-phase high-entropy solid solutions (W-Ti-Ta-Hf)C and (W-Ti-Ta-Hf-Zr)C with a NaCl-type cubic structure (space group Fm-3m) and lattice parameters of 4.4101 Å and 4.4604 Å, respectively. Energy-dispersive X-ray spectroscopy revealed a near-equimolar distribution of metallic components with deviations not exceeding ±1.9 at. %. The addition of ZrC increased the average crystallite size by 84.3% (from 83.6 to 153.1 nm). Both systems achieved comparable relative densities of ~91.75%; however, they exhibited differences in hardness distribution: the four-component system is characterized by a higher average microhardness (1860 HV), while the five-component system exhibits a higher macrohardness HV30 (2008.1). The established correlations between composition, phase formation, microstructure, and properties provide a fundamental basis for the targeted design of high-entropy carbide ceramics with tailored characteristics for high-temperature applications. Full article