Dispersion Of Particles Research Articles

Effect of electromagnetic stirring on interfacial microstructure and mechanical properties of Al/Mg bimetal produced by lost foam compound casting

The Al/Mg bimetal was fabricated using a novel spiral magnetic field-assisted lost foam compound casting (LFCC) process, and the effects of electromagnetic stirring (EMS) on the interfacial microstructure and mechanical properties of the Al/Mg bimetal were investigated. The results indicated that the interface of the Al/Mg bimetal without EMS consisted of Al–Mg intermetallic compounds area (IMCs area) and Al–Mg eutectic area (E area). The Mg2Si particles exhibited a reticulated agglomeration in the IMCs area, and a continuous oxide film was present at the junction of the IMCs area and E area. During shear strength measurement, interface cracks propagated along the oxide film until interface fracture occurred, leading to lower bonding strength at the interface. With EMS applied, there was no change in the phase composition of the Al/Mg interface. The EMS facilitated the diffusion of Si elements in the interface, resulting in the refinement and dispersion of the Mg2Si particles within the IMCs area. Moreover, the Mg2Si content around the oxide film significantly increased, the oxide film remained but became discontinuous. During shear strength measurement, the interface cracks didn’t propagate along the oxide film but extended from the IMCs area to the E area, as a result, the shear strength increased by 29.1% compared to the samples without EMS. The study results demonstrated that applying EMS during the lost foam casting process is a feasible method for improving the microstructure and properties of the Al/Mg bimetals.

Exploring the impact of poly(sodium styrene sulfonate) dispersants’ architecture on their performance in coal water slurry preparation

In this work, the architecture of poly(sodium styrene sulfonate) (PSSNa) dispersants were flexibly tailored by various strategies. Three categories of PSSNa dispersants with different topologies were obtained, namely, linear structured PSSNa (1-A-PSSNa), three-arm star PSSNa (3-AS-PSSNa) and six-arm star PSSNa (6-AS-PSSNa). The molecular weights (Mn) of these dispersants were adjusted in the range of 3200–26,200 g/mol by varying the feeding ratio of monomer to initiator. In addition, the polydispersity index (PDI) of resultant dispersants were also varied by using different polymerization technologies, such as atom transfer radical polymerization (ATRP) and conventional free radical polymerization technique (RP). Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) verified these architecture parameters of resultant PSSNa dispersants. Afterwards, the impact of these architectural factors on the performance of PSSNa dispersants in coal water slurry (CWS) preparation were evaluated. The results revealed that with the Mn of dispersants increased from 9800 to 26,200 g/mol, the apparent viscosity of CWS increased by around 11 %. The comparison between dispersants with approximate Mn (26,200 and 26,900 g/mol) and very different PDI (1.27 and 2.25) indicated that wide PDI are favourable for the performance. This work also confirmed that the topology of dispersants has a significant impact on their performance. The maximum coal loaded can increase from 63.9 % to 64.3 % when 1-A-PSSNa dispersant was replaced by 6-AS-PSSNa. Meanwhile, these architectural factors have a limited impact on the fluid type of CWSs, as all CWSs obtained in this work were pseudoplastic fluids regardless of the used dispersants. The potential mechanism was investigated using various technologies, such as the measurements of zeta potentials, contact angles, and low-field nuclear magnetic resonance spectra. The results revealed that topologizing did not alter the interaction between dispersant and coal surface. However, due to the special features of topological polymers, they can grant adsorbed coal particles with enhanced electrostatic repulsion and steric hindrance, which facilitated the dispersion of coal particles.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

Herein, we present the successful implementation of a composite anode using a conductive additive to enable low iridium (Ir) loadings for PEMWE while maintaining high-performance operation. We use platinum (Pt) black as the conductive additive given its high electrical conductivity, high stability, and a price currently one-fifth that of Ir. Using a high loading of Pt black conductive additive allowed for retained electrode thickness, good dispersion of Ir particles, and drastically decreased sheet resistance at low Ir loadings of 0.10 mgIr cm-2. Compared to a standard Ir oxide anode with high, commercially relevant Ir loading, a composite anode with a low loading of 0.10 mgIr cm-2 achieved an equal current density performance at 1.8 V, translating to a 95% reduction in loading and 80% cost reduction of the anode catalyst materials.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

Herein, we present the successful implementation of a composite anode using a conductive additive to enable low iridium (Ir) loadings for PEMWE while maintaining high-performance operation. We use platinum (Pt) black as the conductive additive given its high electrical conductivity, high stability, and a price currently one-fifth that of Ir. Using a high loading of Pt black conductive additive allowed for retained electrode thickness, good dispersion of Ir particles, and drastically decreased sheet resistance at low Ir loadings of 0.10 mgIr cm-2. Compared to a standard Ir oxide anode with high, commercially relevant Ir loading, a composite anode with a low loading of 0.10 mgIr cm-2 achieved an equal current density performance at 1.8 V, translating to a 95% reduction in loading and 80% cost reduction of the anode catalyst materials.

Improvement of aerogel-incorporated concrete by incorporating polyvinyl alcohol fiber: Mechanical strength and thermal insulation

Aerogel incorporated concrete (AIC) effectively improves its thermal insulation performance. However, the potential mechanical strength degradation in AIC limits its further promotion and application. Fiber reinforcement is an effective means for improving the properties of cement-based materials. However, there is currently a lack research on enhancement mechanisms involved in fiber-reinforced AIC. In this study, polyvinyl alcohol (PVA) fibers with high strength and low thermal conductivity are introduced. The influence on the properties of AIC with various lengths (6–12 mm) and proportions (0–1.2 wt%) of PVA fiber was analyzed, and the mechanism of AIC enhancement was discussed based on microscopic test. The enhancing mechanism of PVA fiber on AIC was studied at microscopic scale to establish new solutions to the development of cementitious materials with both excellent load-bearing capacity and thermal insulation performance. The results revealed a synergistic effect of hydrophobic aerogel and PVA fiber on the fluidity of the mix due to the improvement of particle dispersibility and distribution uniformity. Additionally, the PVA fibers crossed aerogel particles around could inhibit crack expansion caused by aerogel fractures, thus effectively mitigating the loss of strength heat transfer with aerogel incorporation. At the same time, PVA fiber also plays a role in thermal resistance. Specifically, the incorporation of 0.6 wt% 9-mm fibers yielded the best overall reinforcement results, with an increase of 31.4 % and 15.5 % in flexural and compressive strengths, respectively, and a 28.5 % decrease in thermal conductivity. The microstructural tests indicated that incorporating PVA fibers at 0–0.6 wt% could optimize the pore structure, reduce the porosity, and increase the water resistance of AIC. The hydration degree of the cement matrix increased due to Ca2+ adsorption by PVA fibers. This study provides an optimized design strategy incorporating PVA fibers to enhance both the physical properties, mechanical strength, and thermal insulation properties of AIC.

Dispersion of inertial particles in turbulent canopy flows with buoyant and nonbuoyant plumes

Dispersion of inertial particles in turbulent canopy flows with buoyant and nonbuoyant plumes

Unraveling the discrepancies between Eulerian and Lagrangian moisture tracking models in monsoon- and westerly-dominated basins of the Tibetan Plateau

Abstract. Eulerian and Lagrangian numerical moisture tracking models, which are primarily used to quantify moisture contributions from global sources to specific regions, play a crucial role in hydrology and (paleo)climatology studies on the Tibetan Plateau (TP). Despite their widespread applications in the TP region, potential discrepancies in their moisture tracking results and their underlying causes remain unexplored. In this study, we compare the most widely used Eulerian and Lagrangian moisture tracking models over the TP, i.e., WAM2layers (the Water Accounting Model – 2 layers) and FLEXPART-WaterSip (the FLEXible PARTicle dispersion model coupled with the “WaterSip” moisture source diagnostic method), specifically focusing on a basin governed by the Indian summer monsoon (Yarlung Zangbo River basin, YB) and a westerly-dominated basin (upper Tarim River basin, UTB). Compared to the bias-corrected FLEXPART-WaterSip, WAM2layers generally estimates higher moisture contributions from westerly-dominated and distant sources but lower contributions from local recycling and nearby sources downwind of the westerlies. These differences become smaller with higher spatial and temporal resolutions of forcing data in WAM2layers. A notable advantage of WAM2layers over FLEXPART-WaterSip is its closer alignment of estimated moisture sources with actual evaporation, particularly in source regions with complex land–sea distributions. However, the evaporation biases in FLEXPART-WaterSip can be partly corrected through calibration with actual surface fluxes. For moisture tracking over the TP, we recommend using high-resolution forcing datasets, prioritizing temporal resolution over spatial resolution for WAM2layers, while for FLEXPART-WaterSip, we suggest applying bias corrections to optimize the filtering of precipitation particles and adjust evaporation estimates.

Dry sliding wear characteristics of hybrid aluminum alloy with nano-fly ash and nano-yttrium oxide

Aluminum alloys feature impressive levels of strength, ductility, castability, wear resistance, and corrosion resistance, making them highly advantageous for the aviation and automotive industries. This study investigates the dry wear performance of hybrid nanocomposites (HNCs) produced using Al6061 as the matrix, with nano-fly ash (FA) and nano-yttrium oxide (Y2O3) as reinforcing agents, utilizing the stir-casting method. The weight percentage (wt-%) of FA was fixed at 4 wt-%, while the Y2O3 varied from 1 wt-% to 3 wt-%. The specimens were prepared following ASTM-G99 standards and tested using a pin-on-disc apparatus with an E31 steel disc under four different loads: 10 N, 20 N, 30 N, and 40 N. It has been observed that wear rate has been increased with the increase in the applied load. The maximum wear rate has been recorded for the base Al6061 alloy as 5.63 × 10−4 mm3/N-m at 40 N load due to its lower wear resistance and less hardness value. The addition of reinforcement particles in the base alloy results in the grain refinement and improvement in the load-bearing capacity. It has been found that at 40 N load, the Al-6061 alloy reinforced with (4 wt-% FA + 3 wt-% Y2O3) is 56.83% superior in terms of wear resistance (2.43 × 10−4 mm3/N-m) as compared to Al6061 base alloy. The hybrid nano-composite containing 4 wt-% FA + 3 wt-% Y2O3 showed the highest value of microhardness as 123.2 HV, which is 136% higher than that of base alloy due to the higher load-bearing characteristics of the reinforcement particles. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) have been employed to analyze both unworn and worn surfaces, revealing uniform dispersion of reinforcement particles, the formation of an oxide layer, micro-pitting, wear debris, and material delamination. Grain refinement has been examined using the line intercept method (ASTM E1382-97), and X-ray diffraction (XRD) confirmed the elemental composition of the nano-reinforcements.

Effect of hot rolling on microstructures and mechanical properties of SiCp/A356 aluminum matrix composites

This study focuses on the fabrication of SiCp/A356 aluminum matrix composites (AMCs) through stir casting and hot rolling, with the objective of investigating the effects of reduction on microstructural evolution and mechanical properties of SiCp/A356 AMCs. The composites were subjected to hot rolling at 500 °C for varying reduction levels of 30%, 50%, 70%, and 90%. As the reduction increased to 70%, the size of α-Al grains and SiC particle clusters increased. However, further reduction to 90% resulted in the flattening and elongation of α-Al grains, the dispersion of SiC particles into the grains, and a more uniform distribution of SiC particles. The relationship between reduction and SiC particle distribution was established. The ultimate tensile strength (UTS) and yield strength (YS) of SiCp/A356 AMCs showed a gradual increase with increasing reduction. The rolled composite with a 90% reduction exhibited the optimal combination of UTS, YS, and elongation (EL) values. Besides, the strengthening mechanisms were discussed and the dislocation strengthening has a significant contribution to the improvement of YS.

Elaboration and Experimental Characterizations of Copper-Filled Polyamide Micro-Composites for Tribological Applications

Polyamide 66 (PA66) has been used for dynamic bearing applications due to its good wear and abrasion resistance, hardness, and rigidity. PA66/copper micro-composites were studied with respect to micro-mechanical, tribological, and structural properties. A mixing step followed by injection molding was used to develop the different composites: PA66+5 wt.% Cu, PA66+10 wt.% Cu, and PA66+15 wt.% Cu. The morphological aspects of the composites were studied using scanning electron microscopy and microtomography. Good dispersion and adhesion of Cu particles across the matrix were also seen. DSC analysis showed a slight improvement in the % of crystallinity and thermal characteristics of the composites, particularly with 5 wt.% filler. Additional crystallization enhanced the tensile performance of the composites, including the modulus, elongation at break, and tensile strength. Nanoindentation tests also indicated an increase in indentation hardness and elastic modulus as a function of the filler fraction. A pin-on-disk tribometer was used to study the friction and wear properties of neat PA66 and copper-filled PA66 composites. It was found that the composite with 5 weight percent copper had the best wear resistance. A progressive decrease in the friction coefficient was also seen. Copper filler increases hardness and may effectively reduce the temperature at contact interfaces during rotating cycles.

Surface Solid Dispersion of Ketoconazole on Trehalose Dihydrate using Spray Drying to Achieve Enhanced Dissolution Rate.

Ketoconazole (K) is a poorly water-soluble drug that faces significant challenges in achieving therapeutic efficacy. This study aimed to enhance the dissolution rate of ketoconazole by depositing spray-dried ketoconazole (SK) onto the surface of ground trehalose dihydrate (T) using spray drying. Ketoconazole-trehalose surface solid dispersions (SKTs) were prepared in ratios of 1:1 (SK1T1), 1:4 (SK1T4), and 1:10 (SK1T10), and characterized them using particle size analysis, scanning electron microscopy, powder X-ray diffraction, and in vitro dissolution studies. Results showed that the dissolution rates of the dispersions were significantly higher than those of pure ketoconazole, with the 1:10 ratio showing the highest dissolution rate. The improved dissolution was attributed to the formation of a new crystalline phase and better dispersion of ketoconazole particles. These findings suggest that the surface solid dispersion approach could be a valuable method for enhancing the bioavailability of poorly water-soluble drugs.

Eulerian approach for erosion induced by particle-laden impinging jets

Particle dispersion and erosion play an important role in various engineering applications, particularly in impinging jet flows. This study presents a new Eulerian method for characterizing these phenomena in axisymmetric, laminar, and turbulent jets, impinging and transiently eroding a flat wall. The Eulerian mass and momentum conservation equations are solved assuming a one-way coupling between the flow and the particles. The carrier flow boundary layer velocity profiles in the laminar case are validated with analytical solutions. The particle calculation involves two stages, incident and reflected particles, connected via a restitution model. The reflected particles’ results offer insights into secondary erosion areas but are not used for the main erosion calculations. Subsequently, erosion at the eroded surface is computed using an empirical erosion model, followed by the displacement of computational nodes using the linear-elastic, small-strain deformation equations, all of which are solved transiently. The solutions reveal the spatial particle concentrations and momentum for different Stokes numbers: smaller Stokes particles follow the carrier flow streamlines, medium Stokes particles deviate, forming a W-shaped erosion profile, while the largest Stokes particles create a U-shaped profile. This numerical model offers a computationally efficient framework for CFD-based transient erosion calculation due to its Eulerian implementation.

Evaluating the impact of human movement-induced airflow on particle dispersion: A novel real-time validation using IoT technology

Human movement significantly influences local airflow and particle dispersion in indoor environments. Therefore, this study integrates the dynamics of human walking into the analysis of airborne infection risks in a positive pressure isolation ward designed for the protection of immunocompromised patients. Real-time data collection was performed using an anemometer and IoT-based PM sensors to measure airflow velocities and particulate matter (PM) concentrations within a full-scale experimental chamber. Computational Fluid Dynamics (CFD) was used for the numerical simulations, and a User-Defined Function (UDF) code simulated the translational movement of a manikin. The results demonstrated strong agreement with the experimental data, thereby validating the airflow turbulence and Lagrangian-based Discrete Phase Model (DPM) in predicting the airflow velocities and particle transport. The study revealed that human walking substantially enhanced particle dispersion distance by 10-fold compared to static conditions, primarily attributed to intensified air mixing induced by the body movement. Furthermore, the CFD analysis underscored that the direction of walking plays a crucial role in airborne transmission. Specifically, walking away from a patient did not elevate infection risk, whereas approaching a patient significantly increased particle deposition in the patient-occupied region. This study highlights the critical need to consider both movement patterns and directional flow in managing airborne infection risks, contributing to the development of more effective infection control strategies in healthcare settings.

Third harmonic of the dynamic magnetic susceptibility of a concentrated ferrofluid: Numerical calculation and simple approximation formula.

Information about the nonlinear magnetic response of dispersions of magnetic particles is the basis for biomedical applications. In this paper, using analytical and numerical methods, the third harmonic of the dynamic susceptibility of an ensemble of moving magnetic particles in an ac magnetic field with an arbitrary amplitude is studied, taking into account interparticle interactions. A simple approximation formula is proposed to predict the third harmonic as a function of two parameters: the Langevin susceptibility χ_{L}, which is used to estimate the particle dipole-dipole interactions, and the Langevin parameter ξ, which represents the ratio of the energy of the magnetic moment interacting with the magnetic field to the thermal energy. The derived approximation formula corresponds with the known single-particle theories in the limit case of a small particle's concentration and is valid for concentrated dispersions of magnetic particles (with the Langevin susceptibility up to χ_{L}≤3) in high-amplitude ac fields (with the Langevin parameter up to ξ≤10).

Simulation study on flow field regulation of flotation column with stirring device

ABSTRACT Flow field regulation plays an important role in the optimization of column flotation units with agitation function. This paper aims to discuss the regulating effect of baffle design on the flow field in stirred column flotation units by numerical simulation. A series of geometric models of changing baffle structure and layout were established, and detailed flow field simulation analysis was carried out by using COMSOL software. The results show that the internal flow field of the traditional standard cylindrical tank will cause the solid particles to adhere to the wall movement and the bubbles to the middle area, resulting in the uneven distribution of particles and bubbles, and the internal flow field is not conducive to the mineralization process and the stability of the foam layer. This limitation can be significantly improved by introducing baffles. The results show different baffle shapes and layouts are as follows: wide and narrow on top, narrow on the bottom and wide on top, and only arranged at the bottom of the column body, can increase the average turbulent kinetic energy in the collision zone by 22%, 46% and 43%, and the average turbulent dissipation rate by 18%, 43% and 36%, respectively, while maintaining the turbulence intensity in the transport zone. Among them, the baffle plate with wide top and narrow bottom has the best effect. Arranging baffles with a length shorter than 2/3 of the height of the cylinder at the upper part inside the cylinder can also enhance the turbulence intensity in the collision zone, but at the same time, it also increases the turbulence intensity in the transport zone. Moreover, as the length of the baffle decreases, the enhancement effect becomes stronger. Since this method significantly affects the transport zone, it is more suitable for columnar mixing devices. The study also reveals that by adjusting the proportion of wide and narrow baffles, the center of the turbulent region can be laterally shifted to the short baffles, and the flow field distribution can be adjusted. Meanwhile, with the increase in the number of long baffles, the intensity of the flow field in the device will gradually decrease. By moving the center of the turbulent region to the side inlet, the particle dispersion can be accelerated, but in general, the particles will accumulate toward the region with lower turbulence intensity. These findings have important guiding significance for the design and optimization of the flow field of the stirred column flotation unit, which is helpful in improving the agitation uniformity and flotation efficiency.

Unveiling the vibration effect on microstructure and tribological characteristics of AZ80 Mg/AlCrFeMoNb surface composite developed by friction stir processing

This study examines the effects of vibration and AlCrFeMoNb HEA particles on the structure and wear properties of a novel AlCrFeMoNb/AZ80 composite, utilizing friction stir processing (FSP). The findings demonstrated that in comparison to the FSPed sample, the gains in the stir zone of the FSVPed sample demonstrated not only more refining of grains, but also homogeneous dispersion of AlCrFeMoNb particles in the matrix. The effectiveness of FSVP was evident in the enhanced fragmentation of reinforcing particles dispersed in the matrix, which led to a decrease in the mean grain size and significantly improved the shear punch strength. This phenomenon is associated with the elimination of flaws as well as proper scattering of AlCrFeMoNb particles across the matrix.

A deep learning-powered intelligent microdroplet analysis workflow for in-situ monitoring and evaluation of a dynamic emulsion

Accurately determining microdroplet size and uniformity in dispersed phase systems is key for assessing emulsion stability, and essential for quality monitoring and control of emulsion products. Microscopic imaging probes have provided intuitive and advanced insights for characterizing particle microscopic morphology and dispersion in multiphase flows. However, wide size distributions, edge-cutting, overlapping, and high-density target droplets can compromise the image processing accuracy, thereby affecting the precise assessment of emulsion status. In this study, we present a deep learning-based intelligent workflow for microdroplet characterization using an in-situ high-speed particle imaging probe combined with advanced image processing techniques. With the assistance of progressive automatic annotation, a droplet image database was constructed for training the Mask R-CNN model. By incorporating image patching and supervised data augmentation strategies, our well-trained model with accuracy of 95.5% can precisely detect, localize, and segment microscale droplets with various patterns. Additionally, the shape reconstruction module visualizes true shapes of overlapping and edge-cutting droplets, facilitating precise quantification of droplet size information. To validate the feasibility and generalizability of the proposed workflow, we obtained sufficient droplet images through offline sampling during emulsion processes while employing back and front illumination for in-situ monitoring. The automated method achieves precise droplet detection and size measurement, demonstrating its immense potential in online monitoring, evaluation, and control of emulsion quality.

Green and sustainable bamboo based composites with high self-bonding strength

Self-bonding technology is a forming method utilized for the production of bio-composites with notable advantages in terms of high strength and water resistance, while also being free from formaldehyde. The successful achievement of high-strength self-bonding biomaterials has been demonstrated, however, most of these achievements have relied on various surface chemical modifications with limited attention given to exploring non-additive approaches. This study aimed to investigate the feasibility of self-bonding formation through examining the effects of particle dispersion, lignin melting, and chemical bonding, in distinct unit morphologies without the use of any chemical additives. Also, the self-bonding mechanism of bamboo based composites (BBCs) was revealed, by examination of its microstructure, chemical composition and thermal stability. The findings indicated that raw component morphologies based on power, fiber, and bundle all effectively achieved high-strength self-bonding structures at a temperature of 155 °C, a pressure of 55 MPa, and a duration time of 60 min. The density of the BBCs approached that of solid cell wall in bamboo, reaching a maximum of 1.44 g/cm3. The morphology of raw components had significant effect on the self-bonding performance of BBCs, with the powder exhibiting the highest performance, followed by the bundles, and the fibers showing the lowest. The powder-based BBC demonstrated a remarkable flexural strength of 61 MPa, a notable surface hardness of 32.5 kgf/mm and low 24 h thickness swelling of 6.8 %, all much more excellent than those observed in ordinary panels. The BBCs demonstrated the benefits of being environmentally friendly (free from formaldehyde), processing excellent water resistance and strong mechanical strengths. They were suitable for use in high-humidity environments and can meet the requirements for strong load-bearing conditions, even replacing some metal sliding bearing materials.

Enhanced microstructures, mechanical properties, and machinability of high performance ADC12/SiC composites fabricated through the integration of a master pellet feeding approach and ultrasonication-assisted stir casting

Integrating ceramic particles into aluminum matrices poses significant challenges due to their limited wettability and high specific volume ratio. This research focused on developing ADC12/SiC aluminum composites with varying SiC concentrations (1.5, 2.5, and 3.5 wt%) through an innovative fabrication process. Initially, ADC12/SiC master pellets containing a high concentration of homogenously dispersed 1-μm SiC particles were produced. Subsequently, these master pellets were introduced into the molten ADC12 alloy, followed by the dispersion of SiC particles via stir casting assisted by ultrasonication. The study assessed the impact of SiC weight fractions on the microstructures, mechanical properties, and machinability of the fabricated composites. The results revealed significant microstructural improvements and a more even distribution of SiC reinforcement inside the ADC12 matrix after the application of this innovative processing method. Increased SiC concentration led to notable refinement of α-aluminum grains and eutectic Si, as well as a more uniform dispersion of intermetallic phases. Additionally, a substantial increase in tensile properties and hardness was observed with the increment of SiC content. Particularly, the ADC12/3.5 wt%SiC composite exhibited a 46.73% increase in hardness and notable enhancements in yield strength, ultimate tensile strength, and elongation, denoted as 201.7 MPa, 241.1 MPa, and 3.40%, respectively, as compared with those of the unreinforced ADC12 alloy. Moreover, the ADC12/SiC composites demonstrated reduced surface roughness compared to the unmodified ADC12 alloy, indicative of a superior surface finish. With the addition of a high SiC content, the chip morphology was observed to change from continuous to discontinuous following a turning operation.

Effect of Different Porous Size of Porous Inorganic Fillers on the Encapsulation of Rosemary Essential Oil for PLA-Based Active Packaging.

Essential oils are interesting active additives for packaging manufacturing as they can provide the final material with active functionalities. However, they are frequently volatile compounds and can be degraded during plastic processing. In this work Rosmarinus officinalis (RO) essential oil was encapsulated into Diatomaceous earth (DE) microparticles and into Halloysite nanotubes (HNTs) and further used to produce eco-friendly active packaging based on polylactic acid (PLA). PLA-based composites and nanocoposites films based on PLA reinforced with DE + RO and HNTs + RO, respectively, were developed by melt extrusion followed by cast-film, simulating the industrial processing conditions. As these materials are intended as active food packaging films, the obtained materials were fully characterized in terms of their mechanical, thermal and structural properties, while migration of antioxidant RO was also assessed as well as the compostability at laboratory scale level. Both DE and HNTs were able to protect the Rosmarinus officinalis (RO) from thermal degradation during processing, allowing to obtain films with antioxidant properties as demonstrated by the antioxidant assays after the materials were exposed for 10 days to a fatty food simulant. The results showed that incorporating Rosmarinus officinalis encapsulated in either DE or HNTs and the good dispersion of such particles into the PLA matrix strengthened its mechanical performance and sped up the disintegration under composting conditions of PLA, while allowing to obtain films with antioxidant properties of interest as antioxidant active food packaging materials.