Search Results (1,731)

Shrinkage of injection-molded parts is a major challenge for dimensional accuracy, especially for semi-crystalline polymers where crystallization induces pronounced volume change and heat release during cooling. Because packing pressure is effective only before gate or local solidification, multi-stage packing is commonly used to regulate the overall shrinkage behavior. In practice, however, the solidification/transition temperature taken from standard material tests does not necessarily represent the actual in-cavity state behavior under specific cooling rate and pressure history, which compromises the consistency of P–V–T-based shrinkage prediction. In this study, a modified P–V–T-based framework (Tait equation) is developed for polypropylene (PP) by introducing a Thermal Enthalpy Transformation Method (TETM) to determine a process-relevant solidification time and crystallization-completion temperature (including the corresponding target specific volume) directly from in-cavity melt temperature monitoring using an infrared temperature sensor. The novelty TETM utilizes the crystallization-induced enthalpy release to identify the temperature–time plateau, from which one can identify the effective solidification point. Because the Tait equation adopts a two-domain formulation (molten and solidified states), accurate identification of the domain-switching temperature is critical for reliable shrinkage prediction in practical molding conditions. In the experiment execution, the optimum filling time was defined using the minimum pressure required for melt-filling. Four target specific volumes, three melt temperatures, and two mold temperatures were examined, and a two-stage packing strategy was implemented to achieve comparable shrinkage performance under different target specific volumes. A conventional benchmark based on the solidification temperature reported in the Moldex3D material database was used for comparison only. The results show that the target specific volume determined by the TETM exhibits a more consistent and near-linear relationship with the measured shrinkage rate, demonstrating that the TETM improves the robustness of solidification-time identification and the practical usability of P–V–T information for shrinkage control. Full article

Ag and Cu in biodegradable Zn alloys have been the focus of research due to their biocompatible corrosion products, as well as their ability to improve the mechanical properties of the alloy. In this research, the impact of Ag and Cu on the fluidity of biodegradable Zn alloys was evaluated through the spiral fluidity test. Zn–xAg and Zn–xCu alloys containing Ag or Cu in pure Zn at proportions of 0.5, 1, 2, and 3 wt.% were prepared. In the first stage of the study, the casting temperature to be used in the fluidity tests of the alloys was determined by casting pure Zn at different temperatures. Spiral castings of the alloys were then produced and the fluidity lengths in the spiral channel were measured. Test results showed that the mold filling distances decreased with increasing amounts of Ag and Cu, with Cu causing a stronger reduction than Ag at comparable addition levels. When the Ag content in Zn was raised from 0.5 wt.% to 1 wt.%, a significant reduction in fluidity was observed. Formation of CuZn₅ and ε–AgZn₃ phases in the microstructures was identified as the main factor limiting melt flow. These findings provide insights into how Ag and Cu additions influence the castability of Zn alloys, offering guidance for optimizing alloy composition for biodegradable implant applications. Full article

This study investigates the effects of high-pressure compression molding on the molecular orientation and mechanical properties of biomass-derived aliphatic polyamide (PA11). Tensile fracture strength exhibited a significant increase—up to 2.4 times that of untreated samples—under conditions of 1000 kN and 140 °C. Differential Scanning Calorimetry (DSC) and Wide-Angle X-ray Scattering (WAXS) analyses revealed a temperature- and pressure-dependent shift in crystalline phases, suggesting a transition from α’ to phase. The δ’ phase, formed by high-pressure compression molding, is retained even after cooling to room temperature (i.e., Brill transition was not observed). In addition, polarized optical microscopy (POM) observations further supported the presence of changes in molecular orientation. This enhancement (under conditions of 1000 kN and 140 °C) is primarily attributed to the molecular orientation. However, it is also noteworthy that the formation of the δ’ phase is accompanied by an increase in the degree of crystallinity, and that this δ’ phase is retained even after cooling to room temperature without undergoing a Brill transition. In contrast, at 180 °C, although the degree of crystallinity increased, molecular orientation decreased, resulting in reduced tensile strength. These findings indicate that the mechanical properties of PA11 are governed by a complex interplay among phase transitions, molecular orientation, and crystallization, all of which are strongly influenced by temperature and pressure conditions. These findings demonstrate that high-pressure compression molding is an effective method for enhancing the mechanical properties of PA11 through controlled phase transition and orientation Full article

This study investigates the sustainable reuse of industrial enamel frit production waste generated during enamel application processes and evaluates its potential from a process-oriented glass-forming and -shaping perspective. Enamel frit waste collected from an industrial production line in Türkiye was subjected to comprehensive characterization, including XRD, XRF, TG/DTA, dilatometry, and CIE Lab* color analysis, with the primary aim of assessing forming compatibility rather than final product performance. Following calcination and controlled fritting, the waste material was processed through mold-based glass-forming experiments using firing schedules derived from thermal analysis. The results reveal pronounced chemical and thermal heterogeneity among enamel frit production wastes, leading to variable melting behavior across samples. Nevertheless, selected waste compositions exhibited sufficient viscous flow for shaping at reduced firing temperatures of approximately 850 °C. This study demonstrates that selected enamel frit production wastes—obtained from industrial enameling processes in slurry, powder, or granular form—can be reshaped into glass forms under controlled low-temperature conditions. The novelty of this study lies in investigating industrial enamel production frit waste as a reusable material within a circular economy framework, specifically focusing on its application in mold-based glass forming for artistic and educational contexts, thereby fostering collaboration between industrial waste management and glass art practice. Full article

Higher moisture content in wheat benefits processing but impairs storage stability. Current research on quality changes in high-moisture wheat under varying storage temperatures remains limited. This study systematically evaluated wheat with 14% moisture content stored at 15 °C, 20 °C, 25 °C, and 30 °C over 180 d, assessing quality parameters, mycotoxin levels, and fungal community composition. Results indicated that wheat stored at 15 °C and 20 °C maintained stable storage and processing quality. Meanwhile, the concentrations of aflatoxin B₁, deoxynivalenol, and zearalenone in wheat across all storage temperatures remained below their respective regulatory limits of 5.00 μg/kg, 1.00 mg/kg, and 60.00 μg/kg. No visible mold appeared in wheat stored at 15 °C, 20 °C, or 25 °C for 180 d, whereas initial mold characteristics emerged at 30 °C. Fungal community analysis revealed that at 15 °C and 20 °C, the dominant genus shifted from Bipolaris to Cladosporium, while at 25 °C and 30 °C, it rapidly transitioned to Aspergillus. Although fungal richness showed no significant differences, diversity indices varied notably across storage temperatures. These findings provide a theoretical basis for the safe storage of high-moisture wheat. Full article

Microparticle detection technology uses materials that can specifically recognize complex biostructures, such as antibodies and aptamers, as trapping agents. The development of antibody production technology and simplification of sensing signal output methods have facilitated commercialization of disposable biosensors, making rapid diagnosis possible. Although this contributed to the early resolution of pandemics, traditional biosensors face issues with sensitivity, durability, and rapid response times. We aimed to fabricate microspaces using metallic materials to further enhance durability of mold fabrication technologies, such as molecular imprinting. Low-damage metal deposition was performed on target protozoa and Norovirus-like particles (NoV-LPs) to produce thin metallic films that adhere to the material. The procedure for fitting the object into the bio structured space formed on the thin metal film took less than a minute, and sensitivity was 10 fg/mL for NoV-LPs. Furthermore, because it was a metal film, no decrease in reactivity was observed even when the same substrate was stored at room temperature and reused repeatedly after fabrication. These findings underscore the potential of integrating stable metallic structures with bio-recognition elements to significantly enhance robustness and reliability of environmental monitoring. This contributes to public health strategies aimed at early detection and containment of infectious diseases. Full article

This research explores the optimization of mechanical properties and predictive modeling of polylactic acid (PLA) reinforced with boron nitride nanoplatelets (BNNPs) using data-driven machine learning (ML) models. PLA-BNNP composites were fabricated through injection molding, with a focus on how key processing parameters influence their mechanical performance. A Taguchi L27 orthogonal array was applied to assess the effects of BNNP composition (0.02 wt.% and 0.04 wt.%), injection temperature (135–155 °C), injection speed (50–70 mm/s), and pressure (30–50 bar) on properties such as tensile strength, Young’s modulus, and hardness. The results indicated that a 0.04 wt.% BNNP loading improved tensile strength, Young’s modulus, and hardness by 18.6%, 32.7%, and 20.5%, respectively, compared to pure PLA. Taguchi analysis highlighted that higher BNNP concentrations, along with optimal injection temperatures, improved all mechanical properties, although excessive temperatures compromised tensile strength and modulus, while enhancing hardness. Analysis of variance (ANOVA) revealed that injection temperature was the dominant factor for tensile strength (68.88%) and Young’s modulus (86.39%), while BNNP composition played a more significant role in influencing hardness (78.83%). Predictive models were built using machine learning (ML) models such as Random Forest Regression (RFR), Gradient Boosting Regression (GBR), and Extreme Gradient Boosting (XGBoost). Among the ML models, XGBoost demonstrated the highest predictive accuracy, achieving R² values above 98% for tensile strength, 92–93% for Young’s modulus, and 96% for hardness, with low error metrics i.e., Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE). These findings underscore the potential of using BNNP reinforcement and machine learning-driven property prediction to enhance PLA nanocomposites’ mechanical performance, making them viable for applications in lightweight packaging, biomedical implants, consumer electronics, and automotive components, offering sustainable alternatives to petroleum-based plastics. Full article

The flexible micro-structured surface found in biological skins exhibits remarkable drag reduction properties, inspiring applications in the aerospace industry, underwater exploration, and pipeline transportation. To address the challenge of efficiently replicating such structures, this study presents a composite flexible polymer film with a bio-inspired micro-dimple array, fabricated via an integrated process of precision milling, polishing, and micro-injection molding using thermoplastic polyurethane (TPU). We systematically investigated the influence of key injection parameters on the shape accuracy and surface quality of the film. The experimental results show that polishing technology can significantly reduce mold core surface roughness, thereby enhancing film replication accuracy. Among the parameters, melt temperature and holding time exerted the most significant effects on shape precision PV and bottom roughness R_a, while injection speed showed the least influence. Under optimized conditions of a melt temperature of 180 °C, injection speed of 60 mm/s, holding pressure of 7 MPa, and holding time of 13 s, the film achieved a micro-structure shape accuracy of 13.502 μm and bottom roughness of 0.033 μm. Numerical simulation predicted a maximum drag reduction rate of 10.26%, attributable to vortex cushion effects within the dimples. This performance was experimentally validated in a flow velocity range of 0.6–2 m/s, with the discrepancy between simulated and measured drag reduction kept within 5%, demonstrating the efficacy of the proposed manufacturing route for flexible bio-inspired drag reduction film. Full article

Adhesive joint failure remains a critical limitation in the manufacturing of large wind turbine blades, where reliable and reproducible surface preparation methods are required at an industrial scale. This study systematically evaluates the effect of peel ply-induced surface morphology and chemistry on the adhesion performance of glass fiber-reinforced polymer (GFRP) laminates, explicitly examining the relationship between wettability and bonding strength. Five surface conditions were generated during vacuum-assisted resin infusion using different commercial and proprietary peel plies and a smooth mold surface. Despite significant differences in contact angle and surface energy, lap shear testing revealed no significant relationship between wettability and joint strength. Instead, surface roughness-driven mechanical interlocking and adhesive–substrate compatibility dominated performance. Compared to the smooth mold surface, twill-type peel ply–modified adherends increased shear strength by up to 3.9×, while other commercial types of peel-plies presented strength improvements between 2.7 and 3.3×. More compatible adhesive–polymer resin systems exhibited a combination of cohesive and adhesive failures, with no clear dependence on surface roughness. In contrast, when the adhesive is less compatible with the substrate, surface roughness significantly affects the adhesive response, with adhesive failure predominating. The adhesive application temperature showed no measurable effect for practical industrial use. These findings demonstrate that wettability alone is not a reliable predictor of adhesion performance for this class of substrates and confirm peel ply surface modification as a robust, scalable solution for industrial wind blade bonding. Full article

Ozone micro–nano bubbles (OMNBs) are an emerging preservation technology. However, there are few reports regarding their application in controlling postharvest diseases of agricultural products. Radix astragali, as a medicinal and edible plant, is particularly vulnerable to pathogenic microorganisms during postharvest storage, which leads to diminishing the quality and commercial value. In this study, fresh R. astragali inoculated with Penicillium polonicum was treated with different concentrations (2, 3, 4, 5, 6, 8 mg/L) of OMNBs and stored at room temperature for 28 days. The results indicate that 3 mg/L OMNBs application for 8 min effectively inhibited the development of blue mold in fresh R. astragali and preserved its quality. Then, we compared the three different treatments of micro–nano bubbles (MNBs), 3 mg/L O₃, and 3 mg/L OMNBs on physiological and pathological parameters of un-inoculated fresh R. astragali during storage and analyzed the changes in the active ingredients by liquid chromatography and metabolomics. The results indicate that the 3 mg/L OMNBs treatment effectively inhibited the decline in weight loss rate, respiratory rate, firmness, browning index, and ABTS and DPPH radical-scavenging rates, as well as reduced the incidence rate and disease index of fresh R. astragali during storage. The metabolomics results suggest that the 3 mg/L OMNBs application activated the mevalonate pathway (MVA), the methylerythritol phosphate pathway (MEP), and the phenylpropanoid biosynthesis pathway to maintain the content of active ingredients such as terpenoids and flavonoids, and these findings are consistent with the results of HPLC-MS analysis. Full article

To achieve the resource utilization of solid waste generated from the papermaking process, this study proposes a method for preparing sintered bricks by partially replacing shale with paper-mill sludge. The brick samples were prepared through a process of mixing in proportion, extrusion molding, drying and roasting. An orthogonal experimental design was employed to investigate the effects of sintering temperature, raw material proportion, and holding time on the physical and mechanical properties of the bricks. The results indicate that the optimal technological parameters are determined as follows: a raw material proportion (paper-mill sludge:shale) of 30:70, a sintering temperature of 1050 °C, a holding time of 8 h, and a heating rate of 1 °C/min. Under these conditions, the produced paper-mill sludge–shale bricks exhibited a compressive strength of 14.91 MPa, a flexural strength of 8.26 MPa, a water absorption of 12.7%, and a bulk density of 1712 kg/m³. These performance indicators meet the requirements for Grade MU10 specified in the national standard Sintered Common Bricks (GB/T 5101-2017). Regarding microscopic analysis, the SEM results reveal significant liquid-phase sintering within the brick body at 1050 °C, while XRD analysis confirmed the presence of stable quartz, alumina, and hematite phases, which contribute to enhancing the mechanical properties and densification of the bricks. Full article

In this study, bulk metallic glasses (BMGs) of Zr₅₆Cu₂₃Al₁₀Ni_11-xTa_x (x = 0, 0.5, 1, 1.5, 2, and 2.5 at.%) were prepared by copper mold suction-casting. The glass-forming ability, mechanical properties, crystallization kinetics, and corrosion resistance of the as-obtained amorphous alloys were all investigated. Experimental results showed enhanced forming ability of amorphous alloys in the presence of small amounts of Ta element. By adding appropriate amounts of Ta, the supercooled liquid region of bulk metallic glass increased from 64 K to 73 K. The critical diameter of the alloy rod at x = 1, 1.5 rose from 5 mm to 6 mm. The addition of Ta also reduced the sensitivity coefficients of the amorphous alloys to the heating rate during crystallization, while other quantities, like Eg, Ex, and Ep, all incremented. Thus, the addition of Ta declined the temperature sensitivity of amorphous alloy systems. This also increased the energy barrier required for atom rearrangement, nucleation and growth, as well as greatly enhancing the stability of the systems. At 2% Ta content, the plastic strain of the amorphous alloy exceeded 2.6%, and yield strength reached 1900 MPa. In sum, the mechanical properties of the amorphous alloys after the addition of Ta element obviously improved when compared to the original alloy. As Ta content raised, the corrosion current densities of BMGs in different corrosion solutions gradually decreased, while the corrosion potential gradually increased. Full article

Unmanned Aerial Vehicles (UAVs) have become indispensable tools, playing a pivotal role in diverse applications such as rescue missions, agricultural surveying, and air defense. They significantly reduce operational costs while enhancing operator safety, enabling new strategies across multiple domains. The growing demand for UAVs calls for structural components that are not only robust and lightweight, but also cost-efficient. This research introduces a novel approach that employs a pressure distribution map on the external surface of a UAV wing to optimize its internal structure through a variable-thickness TPMS (Triply Periodic Minimal Surface) design. Beyond structural optimization, the study explores a second novel approach with the use of filaments containing chemical blowing agents printed at different temperatures for both the infill and shell, producing varying porosities. As a result, the tailoring of density and weight is achieved through two different methods, and case studies were developed by combining them. Compared to the conventionally manufactured wing, a weight reduction of up to 7% was achieved while the wing could handle the aerodynamic loads under extreme conditions. Beyond enabling lightweight structures, the process has the potential to be substantially faster and more cost-effective, eliminating the need for molds and advanced composite materials such as carbon fiber sheets. Full article

Net-shaped casting processes in the automotive industry have proved to be difficult to simulate due to the complexities of the interactions amongst thermal, fluid, and solute transport regimes in the solidifying domain, along with the interface. The existing casting simulation software lacks the necessary real-time estimation of thermophysical properties (thermal diffusivity and thermal conductivity) and the interfacial heat-transfer coefficient (IHTC) to evaluate the thermal resistances in a casting process and solve the temperature in the solidifying domain. To address these shortcomings, an axial directional solidification experiment setup was developed to map the thermal data as the melt solidifies unidirectionally from the chill surface under unsteady-state conditions. A Dilute Eutectic Cast Aluminum (DECA) alloy, Al-5Zn-1Mg-1.2Fe-0.07Ti, Eutectic Cast Aluminum (ECA) alloys (A365 and A383), and pure Al (P0303) were used to demonstrate the validity of the experiments to evaluate the thermal diffusivity (α) of both the solid and liquid phases of the solidifying metal using an inverse heat-transfer analysis (IHTA). The thermal diffusivity varied from 0.2 to 1.9 cm²/s while the IHTC changed from 9500 to 200 W/m²K for different alloys in the solid and liquid phases. The heat flux was estimated from the chill side with transient temperature distributions estimated from IHTA for either side of the mold–metal interface as an input to compute the interfacial heat-transfer coefficient (IHTC). The results demonstrate the reliability of the axial solidification experiment apparatus in accurately providing input to the casting simulation software and aid in reproducing casting numerical simulation models efficiently. Full article

The fabrication of thin-walled plastic parts has potential in the automotive industry in terms of sustainability and circular economy targets to decrease any harmful effects on the ecosystems, cost and performance. Injection molding of thin-walled automotive parts is more complex in terms of processing defects compared to traditional plastic parts. Optimization of processing parameters is of critical importance to solving problems and defects in the production of thin-walled parts. In this study, the flow length and weight of thin-walled spiral parts (with wall thicknesses of 0.50, 1.50, 2.70 and 3.00 mm) were investigated with theoretical and experimental studies. The theoretical flow length and weight of the thin-walled spiral parts were determined by Moldflow analysis according to the pressure and wall thickness. The correlation graph between theoretical results and experimental measurements was obtained. When the wall thickness of the thin-walled spiral parts increased, the flow length of the thin-walled spiral parts increased. As a result, it was found that the thin-walled spiral part mold could not be filled for wall thicknesses of 0.50 and 1.50 mm at maximum pressure due to decreasing temperature at the flow front. In addition, the thin-walled spiral part mold can be filled for a wall thickness of 2.70 and 3.00 mm. In the correlation study conducted for these values, an agreement of approximately 90% was achieved. However, it was also observed that as the pressure increases, the deviation between the experimental and theoretical results becomes more pronounced. Full article