Role Of Particle Size Research Articles

Role of particle size on the mechanical and microstructural properties of fly ash-based geopolymer

Role of particle size on the mechanical and microstructural properties of fly ash-based geopolymer

Sources and health risks of heavy metals in kindergarten dust: The role of particle size

Particle size effects significantly impact the concentration and toxicity of heavy metals (HMs) in dust. Nevertheless, the differences in concentrations, sources, and risks of HMs in dust with different particle sizes are unclear. Therefore, guided by the definition of atmospheric particulate matter, dust samples with particle sizes under 1000 μm (DT1000), 100 μm (DT100), and 63 μm (DT63) from Beijing kindergartens were collected. The concentrations of HMs (e.g., Cd, Pb, Zn, Ni, Cr, Ba, Cu, V, Mn, Co, and Ti) in dust samples with different particle sizes were measured. Besides, the differences in HM concentrations, contamination levels, sources, and source-oriented health risks in dust samples of different particle sizes were systematically explored. The results show that the concentrations of Mn, V, Zn, and Cd gradually increase with decreasing dust particle sizes, the concentrations of Ba and Pb show a decreasing trend, and the concentrations of Cr, Cu, Ni, and Co display an increasing and then decreasing trend. The degree of contamination of HMs in dust of different particle sizes varies, with Cd being the most dominant contaminant. Compared with DT1000 and DT63, DT100 is the most polluted. In addition, the sources of HMs in DT1000, DT100, and DT63 become more single with decreasing particle size, which may be mainly due to the particle-size effect inducing the redistribution of HMs in different sources. Notably, the potential health risk is higher in DT100 than in DT1000 and DT63. The highest contribution of industrial sources to the health risk is found in DT100, which is mainly caused by highly toxic chromium (Cr). This work emphasizes the importance of considering particle size in risk assessment and pollution control, which can provide a theoretical basis for precise management of HMs pollution in dust.

Linking the size of hard carbon particles with electrochemical response in sodium ion storage

Hard carbon is considered to be one of the most promising anodes for sodium-ion batteries (SIBs) owing to its high capacity and abundant resources. However, the role of particle size on sodium ion storage is unclear, which leads to low capacity and initial coulombic efficiency (ICE) in practical application. In this work, a series of hard carbons with different particle sizes were prepared by an “up to down” strategy using simple grinding and ball-milling method to investigate the effect of particle size on electrochemical response of sodium ion storage. The particle size of hard carbon has negligible effect on initial specific capacity. However, it has a strong effect on the ICE and rate capability. The ICE reduces as the particle size decreases, but the rate performance in reverse. Moreover, impedance analysis and electrochemical kinetics show huge differences for different particle sizes. In-situ Raman technique was also adopted to further illustrate the sodium ion storage mechanism of hard carbon, and an “adsorption-intercalation-pore filling” mechanism is proposed. This work could provide a new perspective for the design of hard carbon materials with suitable structure for efficient sodium ion storage, helping to develop high performance SIBs.

Enhanced Antimicrobial Activity of AgCu Nanoparticles: The Role of Particle Size and Alloy Composition.

AgCu bimetallic· nanoparticles (NPs) represent a novel class of inorganic, broad-spectrum antimicrobial agents that offer enhanced antimicrobial effectiveness and reduced cytotoxicity compared to conventional Ag NP antibacterial materials. This study examines the antimicrobial performance and structural characteristics of AgCu nanoparticles (NPs) synthesized via two distinct chemical reduction processes using PVP-PVA as stabilizers. Despite identical chemical elements and sphere-like shapes in both synthesis methods, the resulting AgCu nanoparticles exhibited significant differences in size and antimicrobial properties. Notably, AgCu NPs with smaller average particle sizes demonstrated weaker antimicrobial activity, as assessed by the minimum inhibitory concentration (MIC) measurement, contrary to conventional expectations. However, larger average particle-sized AgCu NPs showed superior antimicrobial effectiveness. High-resolution transmission electron microscopy analysis revealed that nearly all larger particle-sized nanoparticles were AgCu nanoalloys. In contrast, the smaller particle-sized samples consisted of both AgCu alloys and monometallic Ag and Cu NPs. The fraction of Ag ions (relative to the total silver amount) in the larger AgCu NPs was found to be around 9%, compared to only 5% in that of the smaller AgCu NPs. This indicates that the AgCu alloy content significantly contributes to enhanced antibacterial efficacy, as a higher AgCu content results in the increased release of Ag ions. These findings suggest that the enhanced antimicrobial efficacy of AgCu NPs is primarily attributed to their chemical composition and phase structures, rather than the size of the nanoparticles.

Modelling alkali–silica reaction from micro-computed tomography images: role of particle size and water/cement ratio

An experimental programme was conducted to observe, non-destructively, the influence of aggregate particle size and low water/cement (w/c) ratios on alkali–silica reaction (ASR) in concrete using micro-computed tomography scanning. The results were analysed using a model developed as part of a previous study. ASR expansion and cracking was observed to increase to strain levels of around 0.010 with a decrease in particle diameter up to a ‘pessimum’ diameter of 1–2 mm. Below the pessimum diameter, expansion was low: around 0.001 strain. Analysis using the previously developed model clearly illustrated a transition from above the pessimum diameter, where ASR was the main process occurring, to below this size, where a pozzolanic reaction dominated. ASR expansion increased with a decrease in the w/c ratio, reaching strains of around 0.015. The model indicated that this is fundamentally a result of extended periods of restraint of ASR gel around aggregates, ultimately ending in much greater expansion when fracture eventually occurred. Additionally, cracking of aggregate coincided with an accelerated rate of expansion in mixes with w/c ratios below 0.6.

Fine-Tuning Filter Cake Sealing Performance: The Role of Particle Size in Hematite Weighted Water-Based Drilling Fluid.

Three hematite grades with different particle sizes (i.e., large, medium, and small) were evaluated, and the selection criterion was median particle size. The investigation involves the following stages: rheology, filtration, and filter cake formation. Different rheological models including Bingham, Power law, Herschel-Bulkley, and Robertson-Stiff were implemented to find the optimum model for characterizing fluid behavior. The results showed that medium-sized hematite particles produced the highest filtration volume, filter cake thickness, and filter cake permeability. These results were confirmed when a varied pore distribution filtration medium was used. The NMR results showed the same trend where the highest reduction in core porosity was found when a medium-size particle distribution was used. There is a minimum alteration in the rheological behavior of the drilling fluid as the particle size was varied, and the drilling fluids showed a shear-thinning behavior and were best described by the Herschel-Bulkley model. Particle size ratio emerges as a key factor for controlling and enhancing the filtration properties and filter cake characteristics.

Role of particle size in modulating starch digestibility and textural properties in a rye bread model system

In cereal products, the use of flour containing clusters of intact cells has been indicated as a potential strategy to decrease starch digestion. Rye possesses more uniform and thicker cell walls than wheat but its protective effect against starch digestion has not been elucidated. In this study, rye flours with three different particle sizes, large (LF) (∼1700 μm), medium (MF) (∼1200 μm), and small (SF) (∼350 μm), were used to produce model bread. The textural properties of these breads were analysed using Textural Profile Analysis (TPA). The starch digestibility of both the flour and the bread was measured using Englyst’s method, while the presence of intact cell clusters was examined using Confocal Laser Scanning Microscopy (CLSM). Additionally, the disintegration of bread digesta during simulated digestion was assessed through image analysis. CLSM micrographs revealed that bread made with MF and LF retained clusters of intact cells after processing, whereas bread made with SF showed damaged cell walls. Starch digestibility in LF and MF was lower (p ≤ 0.05) than that in SF. Bread produced with MF and LF exhibited the least (p ≤ 0.05) cohesive and resilient texture, disintegrated more during digestion, and exhibited higher starch digestibility (p ≤ 0.05) than bread made with SF. These results highlight the central role of bread texture on in vitro starch digestibility.

Molecular dynamics simulations of nanoparticle sintering in additive nanomanufacturing: The role of particle size, misorientation angle, material type, and temperature

Additive nanomanufacturing, where nanoparticles (NPs) are generated via laser material ablation and sintered via laser, permits the fabrication of novel electronic devices with adequate flexibility, such as tunable material composition, adjustable sintered state, and a wide selection of substrates—including biodegradable ones—to name a few. The laser energy input often needs to be carefully balanced between achieving adequate sintering and avoiding substrate damage. The sintered state of NPs, a key influencing factor of the resistivity of electronic circuits, depends not only on temperature (the result of laser energy input), but also on NPs size, size ratio, and crystallographic misorientation. While the minuteness of NPs and the transient nature of their sintering (typically within a nanosecond) make direct experimental evaluation of such parameters challenging, the length and time scales are uniquely suitable for molecular dynamic (MD) studies. This study utilizes MD to investigate the sintering characteristics of silver and copper NP doublets at different temperatures and examines the effects of NP size, size ratios, misorientation angle (including both tilt and twist), and material type. A mathematical framework to describe the characteristic sintering time, i.e., time needed for a NP doublet to achieve a given normalized neck size, was proposed based on MD results.

Yield stress anomaly and creep of single crystal Ni-base superalloys – Role of particle size

In the present work we subject the single crystal Ni-base superalloy ERBO1 (CMSX 4 type) to constant strain rate (CSR) and creep testing at temperatures between 1023 and 1223 K. Three material states are considered which have similar particle volume fractions >60% but differ in γ′-particle sizes (material states S, M and L of particle sizes: 240, 390 and 540 nm). In constant strain rate testing, a yield stress anomaly is observed for all three material states, with a yield stress maximum at 1073 K. This increase of strength with increasing temperature is not observed during creep testing at significantly lower deformation rates in this low temperature high stress creep regime, where different elementary deformation mechanisms govern CSR and creep behavior. In contrast, in the low stress high temperature creep regime, stress/strain rate data pairs from CSR creep tests both show decreasing strength with increasing temperature. It is found that in both types of tests the material state M shows the highest strength (highest yield stress and lowest creep rate). This can be rationalized based on a scenario where both, γ-channel and γ′-particle dislocation activities are important. Diffraction contrast transmission electron microscopy is used to study the relevant elementary deformation processes. Details of dislocation arrangements are discussed with a special focus on the role of Kear Wilsdorf (KW) locks, γ′-particle shearing by superlattice stacking faults (extrinsic and intrinsic) and dislocation climb.

Size effect of dynamic bioactive magnetic particles on regulated isolation of tumor cells

Circulating tumor cells (CTCs) are critical biomarkers in cancer metastasis, yet their isolation from the bloodstream remains a challenging task due to their low abundance. This study introduces a method for the efficient isolation of CTCs, utilizing dynamic biointerface-based magnetic particles (DBMPs), with a particular emphasis on the role of particle size. We have developed three distinct sizes DBMPs specifically tailored for effective CTCs interaction, leveraging the unique properties of polydopamine (PDA) coatings and phenylboronic acid (PBA)-modified capture peptides through reversible catechol-boronate interactions. Comparative analysis of DBMPs of varying sizes was assessed under uniform experimental conditions for their capture and release efficiencies. The findings reveal a clear distinction: smaller particles (DBMP1 and DBMP2) achieved greater efficiency in capturing CTCs, whereas the larger particles (DBMP3) were more effective in releasing them. This difference is ascribed to the varied interaction dynamics between the particles and CTCs. Furthermore, we have fine-tuned DBMP3 to optimize CTC capture while still maintaining a high efficiency in cell release. The integration of these DBMPs into a magnetic isolation framework is poised to significantly enhance CTCs isolation methods, marking a pivotal advancement in cancer diagnostics and management.

Bioavailability of selenium nanoparticles in soil and plant: the role of particle size

The application of selenium nanoparticles (Se NPs) in agriculture has garnered significant attention, yet there remains a knowledge gap regarding the correlation between the size of Se NPs and their availability in soil. To address this gap, adsorption experiments, soil column experiments, and pot experiments were conducted to investigate the relationship between the availability in soil of Se NPs and their particle size. The results showed that the adsorption capacities of Se NPs with various sizes (30, 50, 80, 110 nm) to fulvic acid (FA) was decreased with increasing particle sizes and pH. Small sized Se NPs (30 nm) are more stable because they adsorb more organic matter, which significantly decreases aggregation. Moreover, the mobility of Se NPs was decreased by increasing clay content in soil and particle size. These results demonstrated that small-sized Se NPs have higher bioavailability than large-sized Se NPs. The Se content in rhizosphere soil and Brassica chinensis shoot was significantly increased by 319.4% and 220.2% upon exposure to Se NPs (30 nm), higher than that for others (50, 80, 110 nm and 2 µm). The reason is that small-sized Se NPs are more stable in the soil, more easily migrate from the non-rhizosphere to the rhizosphere and interact with crop roots, leading to increased root exudations. These interactions recruit beneficial microorganisms in the rhizosphere. In turn, the improved root exudations and the presence of these microorganisms enhance the bioavailability of Se NPs. Linear regression analysis indicated that the size of soil-applied Se NPs should fall within the range of 11–631 nm, as those outside of this range may not meet the standard for Se-enriched food. Besides, the nutrient accumulation in leaves promoted photosynthesis (81.1%) and increased the yield (113.1%) of Brassica chinensis by small-sized Se NPs (30 nm). Therefore, these information highlights the critical role of Se NPs size in crop Se biofortification for agriculture production.

Distribution of Filler in Polymer Composites. Role of Particle Size and Concentration

Distribution of Filler in Polymer Composites. Role of Particle Size and Concentration

Exploiting droplet impact-driven flows and jetting to guide and extract particles from particle-laden droplets

The low concentration of target particles in liquids necessitates their enrichment to a measurable level to provide precise and accurate analytical results. However, the enrichment and extraction of the adsorbed target particles from the droplets remains a challenge. The existing stimuli-responsive strategies for particle enrichment and extraction are not always desirable, as they depend on various parameters, including charge, dielectric constant, magnetic state, size of the particles, etc., which limits their applicability. An ideal method should be capable of extracting particles from the target droplet, irrespective of particle properties, and the process should be fast, preferably in an additive and electrode-free environment. This article presents an efficient strategy for realizing particle extraction based on droplet impact-driven fluid flows under isothermal, non-evaporative, and additive/electrode-free environments. The process relies on the droplet impact-driven redistribution of the particles at the liquid–air interface and the generation of a particle-rich satellite droplet at a designed Weber number, We ∼ 65. The impact dynamics and flow profiles are investigated using simulation and high-speed imaging, and the droplet impact-driven particle extraction is demonstrated experimentally. The particle extraction efficiency is estimated by weight percentage and optical profilometry analysis, and at optimal impact conditions, an extraction efficiency of about 90% is achieved, which takes only a few milliseconds to complete. The role of particle size, surface tension, and We on the extraction efficiency is investigated experimentally. Since the developed method is based on flows, it could be a potential candidate for the extraction/enrichment of various particles/biological entities and does not require complicated setups/skills.

Enhancing the mechanical performance of E‐glass fiber epoxy composites using coal‐derived graphene oxide

AbstractIn this study, we compare the effect of various precursor‐based graphene oxide (GO) nanofillers on enhancing the mechanical performance of E‐glass fiber‐reinforced epoxy resin composites (EGFPs). GO derived from bituminous coal (BC‐GO) and graphite (Gr‐GO) were dispersed into an epoxy resin matrix. The resulting mixture was combined with E‐glass fiber mats using vacuum‐assisted resin infusion molding. Notable improvements (38.9% in flexural strength, 22.9% in tensile strength, and 21.6% in impact strength) were observed in BC‐GO‐reinforced EGFPs at 0.25 phr loading of BC‐GO. The improvements for Gr‐GO‐reinforced EGFPs were 28%, 9.3%, and 6.8%, respectively. XRD analysis of BC‐GO showed a diffraction peak at 2θ = 20.9°. Except for this peak, no other crystalline peaks were observed when BC‐GO was incorporated into EGFPs. FTIR spectra of both composite samples, with or without the nanofiller, were similar due to the spectral peaks overlap. TEM demonstrated the exfoliated morphology of BC‐GO in EGFPs. These findings underscore the potential of BC‐GO as a cost‐effective reinforcement for polymer nanocomposites across various industrial applications, including the development of lightweight and strong materials for aerospace and automotive industries, protective coatings, petroleum, and aerospace production systems.Highlights BC‐GO demonstrates superior mechanical performance compared to Gr‐GO in EGFPs. 0.25 phr BC‐GO improves 38.9% flexural, 22.9% tensile, and 21.6% impact strengths. Beyond 0.25 phr, BC‐GO and Gr‐GO showed a decline in mechanical enhancement. Role of particle size, loading & adhesion to matrix analyzed using XRD, FTIR, and DLS. Coal‐GO is an attractive alternative nanofiller for EGFPs.

The role of particle size and other properties on silo discharge behaviour of chipped wood biomass

To achieve net-zero carbon emissions by 2050, the UK government emphasizes the pivotal role of sustainable bioenergy in electricity, transportation, and heating. However, challenges persist in handling biomass particulate solids in production facilities, leading to economic impacts. This study investigates the flow characteristics of stemwood chips from four tree species using a novel drum chipper. Experimental analyses include bulk density measurements, silo discharge studies, biomass flow property assessments, and wall friction measurements. Comparative analyses are performed using Jenike's procedure for building wedge-shaped silos, with a focus on predicting the critical opening size to prevent arching. Additionally, the paper delves into the creation of statistical models aimed at identifying key factors influencing the flow behaviour during silo discharge. Emphasis is placed on understanding potential discrepancies between theoretical predictions and experimental results concerning critical silo openings for arch-free discharge. The results contribute to understanding the factors influencing the flow behaviour of wood chips, informing silo design considerations. Our findings suggest limitations in applying traditional silo design methods, urging further research for more accurate predictions.

Adsorption behavior of triclosan on polystyrene nanoplastics: The roles of particle size, surface functionalization, and environmental factors

Nanoplastics (NPs) contribute substantially to the transport of waterborne pollutants. Triclosan (TCS) has a high potential to contact with NPs because of their prevalence in natural waters. Herein, this study investigated the adsorption behavior of TCS on differently sized and functionalized polystyrene (PS) NPs. The effects of environmental factors such as pH, salinity, and dissolved organic matter (DOM) were also evaluated. Results suggest that the adsorption equilibrium constant (kd) of TCS in pristine PSNP suspensions followed the order as: PSNPs-50 nm (4.39 L·g−1) > PSNPs-100 nm (2.78 L·g−1) > PSNPs-200 nm (2.59 L·g−1) > PSNPs-500 nm (1.36 L·g−1) ≈ PSNPs-900 nm (1.36 L·g−1). For the functionalized PSNPs (i.e., PSNPs-COOH, PSNPs-NH2), the values of specific surface area normalized kd called kd, SSA were higher than those of pristine PSNPs. Meanwhile, TCS adsorption on two functionalized PSNPs remained stable and then decreased as salinity increased, while an opposite trend was observed toward pristine PSNPs. All these suggested that physicochemical properties of PSNPs (e.g., particle size and surface functional groups) are important factors influencing their adsorption capacity. When the solution pH raised, the adsorbed amounts of TCS on all tested PSNPs prone to decline. However, DOM only affected the adsorption behavior of PSNPs-50 nm, probably owing to its aggregation with tiny PSNPs and the induced secondary adsorption.

Modeling of Cohesive Metal-induced Agglomeration in High Temperature Gas Fluidization: The Role of Particle Size

Modeling of Cohesive Metal-induced Agglomeration in High Temperature Gas Fluidization: The Role of Particle Size

Aggregation behavior of polyethylene microplastics in the nearshore environment: The role of particle size, environmental condition and turbulent flow

Estuary and coastal waters are hotspot areas for microplastics (MPs) pollution. MPs of varying sizes converge in this complex nearshore environment. Aggregation is an important process that affects the transport and fate of MPs in the aqueous environment. Nevertheless, the influence of different factors on the aggregation behavior and the aggregates structure of MPs is unclear. In this study, the aggregation behavior and the aggregates structure of polyethylene microplastics (PEs) of different sizes under the impact of nearshore environmental conditions (i.e., salinity gradient, dissolved organic matter-DOM, turbulent flow) were investigated. The results show that particle size was the dominant factor affecting the stability of PEs in the aqueous environment, and the critical coagulation concentration (CCC) of PEs shifts to the right with increasing size. It was also found that the size of PEs stable aggregates is negatively correlated with the turbulent kinetic energy dissipation rate. The particle size of PEs can significantly affect the fractal dimension (FD) of stable aggregates, and the smaller the particle size, the more compact the aggregates formed. Moreover, salinity and DOM control the size and FD of PEs stable aggregates through different mechanisms. The findings of this study will be helpful for the prediction of the transport and fate of MPs in the aqueous environment.

Digital light processing of high-strength hydroxyapatite ceramics: Role of particle size and printing parameters on microstructural defects and mechanical properties

Dense hydroxyapatite (HA) bars were fabricated using digital light processing. The roles of HA median particle size (MPS), curing depth-to-layer thickness ratio (CD/LT), and debinding process on the printing/debinding flaws and flexural strength of the sintered parts were investigated. Commercial HA was milled for different times to provide powders with an MPS ranging from 0.3 to 2.7 µm. Thermal debinding led to delamination and vertical cracks, which decreased with increasing MPS; the minimum value required to fabricate specimens with appreciable flexural strength was 0.9 µm. At a given MPS (2.7 µm), the CD/LT varied between 1.4 and 3.3, indicating a progressive disappearance of the above major flaws. Finally, the positive effect of water debinding prior to thermal debinding on reducing crack formation was demonstrated. After optimisation, the bars achieved a flexural strength greater than 100 MPa, which is the highest value among dense HA fabricated using lithography-based techniques.

The Role of Particle Size and Shape on the Recovery of Copper from Different Electrical and Electronic Equipment Waste

The increasing world population and the development of technology have boosted the demand for electrical and electronic equipment (EEE). Equipment that has completed its life cycle causes serious damage to the environment due to its toxic components. In addition, it contains many more base metals (copper, aluminum, nickel, lead, tin, etc.) and precious metals (silver, gold, palladium, platinum, etc.) compared with a run of mine ore. Recycling these values with an economic and environmental understanding will ensure sustainability and prevent the rapid depletion of natural resources. Specific gravity, magnetic, electrostatic, optical, surface, thermal, and other property differences between particles as well as the shape, size, and distribution of individual particles directly determine the success of the recycling process. By determining the behavior of the particles during enrichment and producing grains suitable for enrichment with better performance in the size reduction stage, the quality of the concentrate to be subjected to the final chemical/metallurgical treatment will be enhanced. The main aim of this study is to reveal the effect of particle size and shape properties on the recovery of valuable metals from two different waste electrical and electronic equipment (WEEE) sources, end-of-life printed circuit boards and waste electric wires, using environmentally friendly, easier-to-use, and cost-effective mechanical, physical, and physiochemical processes. Deciding on the most suitable enrichment process after detailed characterization of the products obtained from different comminution equipment and their particle size and shape directly affected the amount, content, and recovery of the final concentrate.