Particle Deposition Patterns Research Articles

Experimental measurements of particle deposition in the human nasal airway.

Intranasal drug delivery is a promising non-invasive method for administering both local and systemic medications. While previous studies have extensively investigated the effects of particle size, airflow dynamics, and deposition locations on deposition efficiency, they have not focused on the thickness of deposited particles, which can significantly affect drug dissolution, absorption and therapeutic efficacy. This study investigates the deposition patterns of dry powder particles within the nasal airway, specifically examining how factors such as flow rates, particle size, and particle cohesiveness influence deposition patterns and their thickness. Using optical coherence tomography (OCT), this study assessed the deposition behaviour of three different lactose powders in a reconstructed nasal airway model at three key anatomical locations under varying flow rates (15, 35 and 55 L/min). Computational fluid dynamics (CFD) simulations were conducted to complement the experimental data, demonstrating the airflow dynamics in the nasal airway and highlighting recirculation zones that impact deposition patterns. The results revealed that the anterior section of the nasal airway is particularly effective at capturing particles, with localised flow patterns playing a critical role in particle accumulation. These flow patterns, combined with particle size and cohesiveness, are key factors in determining where and how particles cluster, leading to thicker deposition in specific areas of the nasal airway. This study addresses the gap in understanding how these factors influence deposition thickness and spatial distribution, ultimately contributing to the optimisation of nasal drug delivery systems.

Numerical Simulation of the Distribution Patterns of Particle Deposition on the Vertical Wall Behind Near-Wall Heat Source

Near-wall heat sources have a crucial part to play in the process of particle deposition. Thus, this study investigates the impact of the near-wall heat source on the distribution patterns of particle deposition on the vertical wall behind the heat source, taking into account the variability in heat source temperatures and distances from the vertical wall. A model based on the Eulerian–Lagrangian method was established for tracking the motion trajectories of 1000 particles with a density of 1400 kg/m3 and a particle size range of 0.01–10.0 μm. The temperature field, airflow field, and particle deposition distribution in six cases were analyzed. It was shown that the heat source temperature significantly affectis the temperature field, airflow field, and particle deposition distribution on the vertical wall behind the heat source. This study demonstrated that as the temperature rises, the quantity of particles deposited in the upper-right region of the vertical wall decreases more noticeably. The quantity of particles deposited onto the vertical wall is inversely related to the distance between the near-wall heat source and the vertical wall. On one hand, the deposition distribution law serves as a foundation for advancing the technology aimed at removing suspended particles via thermal plumes. On the other hand, it provides critical insights for addressing the challenges associated with harmful particle deposition linked to the attachment effects of thermal plumes.

Numerical simulation and experimental analysis of aerosol deposition: Investigating nozzle effects on particle dynamics and deposition

Aerosol deposition (AD), also known as vacuum kinetic spray (VKS), is used to deposit dense ceramic films onto a substrate surface at room temperature. One predominant factor influencing the overall deposition process is the nozzle geometry, which significantly impacts the quality, shape, and thickness of the coating. To evaluate the effect of nozzle geometry in AD, particle trajectory and impact velocity were investigated via computational simulation. A Eulerian-Lagrangian model was used to simulate the gas flow, particle in-flight behavior, as well as particle deposition characteristics on a flat substrate. Three common nozzle geometries in AD were utilized: a converging-diverging nozzle with a slit cross-section (CD-Slit), a converging-barrel nozzle with a slit cross-section (CB-Slit), and a converging-diverging round (CD-Round) nozzle. Moreover, suitable drag coefficient and Nusselt number correlations were used to account for compressibility and rarefaction effects on particle dynamics and heat transfer. The simulation results were compared to the deposition pattern obtained experimentally. The results demonstrate that shape of the nozzle has profound effect on the particle impact velocity and deposition pattern. The CD-Round nozzle provides uniform, thinner coatings ideal for extensive surfaces at a slower deposition rate. In contrast, the CB-Slit nozzle is optimized for maximum coating thickness in narrow, thick linear patterns. The CD-Slit nozzle achieves high deposition rates with uniform coatings and a distinctive cat-ear shaped pattern.

Numerical modeling of particle deposition in a realistic respiratory airway using CFD-DPM and genetic algorithm.

In this study, a realistic model of the respiratory tract obtained from CT medical images was used to solve the flow field and particle motion using the Eulerian-Lagrangian approach to obtain the maximum particle deposition in the bronchial tree for the main purpose of optimizing the performance of drug delivery devices. The effects of different parameters, including particle diameter, particle shape factor, and air velocity, on the airflow field and particle deposition pattern in different zones of the lung were investigated. In addition, a genetic algorithm was employed to obtain the maximum particle deposition in the bronchial tree and the effect of the aforementioned parameters on particle deposition. Reverse flow, vortex formation, and laryngeal jet all affect the airflow structure and particle deposition pattern. The mouth-throat region had the highest deposition fraction at various flow rates. A change in the deposition pattern with an increased deposition fraction in the throat was observed owing to the increased diameter and shape factor of the particles, resulting from the higher inertia and drag force, respectively. The particle deposition analysis showed that three parameters, shape factor, diameter, and velocity, are directly related to particle deposition, and the diameter is the most effective parameter for particle deposition, with an effect of 60% compared to the shape factor and velocity. Finally, the prediction of the genetic algorithm reported a maximum particle deposition in the bronchial tree of 17%, whereas, based on the numerical results, the maximum particle deposition was reported to be 16%. Therefore, there is a 1% difference between the prediction of the genetic algorithm and the numerical results, which indicates the high accuracy of the prediction of the genetic algorithm.

Three-dimensional finite element analysis of turbulent crude oil flow and solid particle deposition patterns in circular curved pipelines

This study presents a numerical investigation of turbulent crude oil flows in circular curved pipelines, with a focus on the deposition patterns of solid particles within the fluid. Simulations were conducted using the Reynolds–Averaged Navier–Stokes equations coupled with the k–ε turbulence model to examine the influence of structural characteristics, such as bend curvature angle and bend curvature radius, on flow dynamics and particle deposition. The results reveal that the complex flow patterns generated by these geometric features significantly affect pressure gradients and particle trajectories. Specifically, the study shows that turbulent flows within bends exhibit intricate behaviors, with deposition patterns being strongly influenced by the pipeline’s geometric parameters. Sand particles, commonly present in petroleum flows, are found to be more effectively transported in pipes with larger curvature angles, while they exhibit a higher propensity to settle at smaller curvature angles and larger bend curvature radii. Furthermore, the simulations indicate that the majority of deposited particles accumulate on the inner wall immediately downstream of the elbow entrance.

Simulation of electrostatic particulate matter sensor regeneration based on the particulate deposition patterns

PurposeThis study aims to establish a multi-physics-coupled model for an electrostatic particulate matter (PM) sensor. The focus lies on investigating the deposition patterns of particles within the sensor and the variation in the regeneration temperature field.Design/methodology/approachComputational simulations were initially conducted to analyse the distribution of particles under different temperature and airflow conditions. The study investigates how particles deposit within the sensor and explores methods to expedite the combustion of deposited particles for subsequent measurements.FindingsThe results indicate that a significant portion of the particles, approximately 61.8% of the total deposited particles, accumulates on the inside of the protective cover. To facilitate rapid combustion of these deposited particles, a ceramic heater was embedded within the metal shielding layer and tightly integrated with the high-voltage electrode. Silicon nitride ceramic, selected for its high strength, elevated temperature stability and excellent thermal conductivity, enables a relatively fast heating rate, ensuring a uniform temperature field distribution. Applying 27 W power to the silicon nitride heater rapidly raises the gas flow region's temperature within the sensor head to achieve a high-temperature regeneration state. Computational results demonstrate that within 200 s of heater operation, the sensor's internal temperature can exceed 600 °C, effectively ensuring thorough combustion of the deposited particles.Originality/valueThis study presents a novel approach to address the challenges associated with particle deposition in electrostatic PM sensors. By integrating a ceramic heater with specific material properties, the study proposes an effective method to expedite particle combustion for enhanced sensor performance.

Polymer-Mediated Crack Suppression in Deposit of Nanoellipsoids.

Uniform distribution of particles and crack suppression in dried particulate deposits are major challenges for applications in coating and printing technologies. To address this, we investigated the impact of the addition of a water-soluble polymer, poly(vinyl alcohol) (PVA), on the evaporative self-assembly and kinetics of crack formation in deposits of anisotropic colloids. The fluid flow inside the drying drop is significantly altered due to polymer-mediated adsorption of ellipsoids to the drop surface. The competition between outward capillary flow and Marangoni flow developed in the drying colloid-polymer dispersion drop dictates the distribution of particles in the final dried patterns. The deposits formed by drying drops of ellipsoids dispersed in PVA solutions show three distinct patterns depending on the PVA concentration. A transition from ring-like deposit to uniform deposition with intermittent cracks was observed for a critical PVA concentration of 0.3 wt %. Radial as well as annular cracks were observed in the case of no PVA, while only annular cracks were formed in the dried patterns as the PVA content increased, thus indicating the change of capillary stresses in the films. Analyses of the particle dynamics and deposition patterns confirmed the effectiveness of gelation-driven crack prevention. This method offers a facile and straightforward solution for obtaining crack-free coatings in drying-mediated colloidal nanoparticle assembly.

Numerical study on the effect of nozzle-converging length on the aerosols collection efficiency and deposition on the impaction plate of a multi-nozzle inertial impactor.

Accurately locating deposited particles on the impaction plate of an inertial impactor is crucial for mineralogical and geochemical analysis. Since traditional methods relying on filter analysis are costly and time-consuming, this study delves into the numerical examination of the impact of nozzle-converging length (NCL) on the collection efficiency and depositional arrangements of various fine aerosol particles. Three distinct nozzle-converging lengths (NCL = 3, 7, and 13 mm) were simulated and rigorously compared for their performance in particle collection within an eight-nozzle inertial impactor . Comprehensive analysis reveals that varying NCL does not significantly impact the collection efficiency of any investigated particle, with variations within 12% across all sizes in this study. Moreover, while NCL adjustments influence the settling ratio of primary depositions, these effects remain under 35% for all different-sized and shaped particles studied in this article. Furthermore, after examining 120 cases and averaging the collection efficiency for particles of a constant aerodynamic diameter, our findings indicate that the efficiency variations across the three distinct geometries remain under 5%. Consequently, we conclude that the head design of this impactor is independent from NCL. Notably, shorter NCLs result in denser particle accumulation near the nozzle outlet on the impaction plate, with this effect more pronounced for coarser particles. In summary, this research provides valuable insights into the role of nozzle-converging length in aerosol particle collection efficiency and deposition patterns, offering crucial guidance for particle classification and sampling methodologies eliminating the need for filter analysis.

The impact of particle deposition on collection efficiency of electret fibers

This study presents a microscale simulation method that allows one to study the impact of particle loading on the aerosol capture efficiency of an electrostatically charged filter. This was done by considering a bipolarly charged fiber loaded with different amounts of neutral and charged particles with a diameter of 300 nm. The simulations predicted the deposition pattern of the aerosol particles as well as their impact on the electrostatic field of the bipolar fiber. The particle-loaded fiber was then challenged with aerosol particles in the range of 50 nm to 1 μm and with different charge polarities to study how the electrostatic field of the deposited particles interacts with that of the fiber to attract or repel the incoming airborne particles. More specifically, our simulations revealed that particle deposition can enhance the capture efficiency of a bipolar fiber when it is challenged with small particles (smaller than about 400 nm) regardless of the charge polarity of the airborne or deposited particles. The numerical simulations reported in this paper were conducted using the ANSYS CFD code enhanced with in-house subroutines to superimpose the electrostatic field of the deposited particles to that of the bipolar fiber and to include Brownian, polarization, and Coulomb forces in particle trajectory calculations.

Is the mouse nose a miniature version of a rat nose? A computational comparative study

Background and objectiveAlthough the mouse is a widely used animal model in biomedical research, there are few published studies on its nasal aerodynamics, potentially due to its small size. It is not appropriate to assume that mice and rats' nasal structure and airflow characteristics are the same because the ratio of nasal surface area to nasal volume and body weight is much higher in a mouse than in a rat. The aim of this work is to use anatomically accurate image-based computational fluid dynamic modeling to quantitatively reveal the characteristics of mouse nasal airflow and mass transport that haven't been detailed before and find key differences to that of rat nose, which will deepen our understanding of the mouse's physiological functions. MethodsWe created an anatomically accurate 3D computational nasal model of a B6 mouse using postmortem high-resolution micro-CT scans and simulated the airflow distribution and odor transport patterns under restful breathing conditions. The deposition pattern of airborne particles was also simulated and validated against experimental data. In addition, we calculated the gas chromatograph efficiency of odor transport in the mouse employing the theoretical plate concept and compared it with previous studies involving cat and rat models. ResultsSimilar to the published rat model, respiratory and olfactory flow regimes are clearly separated in the mouse nasal cavity. A high-speed dorsal medial (DM) stream was observed, which enhances the delivery speed and efficiency of odor to the ethmoid (olfactory) recess (ER). The DM stream split into axial and secondary paths in the ER. However, the secondary flow in the mouse is less extensive than in the rat. The gas chromatograph efficiency calculations suggest that the rat may possess a moderately higher odorant transport efficiency than that of the mouse due to its more complex ethmoid recess structure and extensive secondary flow. However, the mouse's nasal structure seems to adapt better to varying airflow velocity. ConclusionsDue to the inherent structural disparities, the rat and mouse models exhibit moderate differences in airflow and mass transport patterns, potentially impacting their olfaction and other behavioral habits.

The influences of jet axis switching and aerodynamic focusing on aerosol deposition in converging–diverging slit impactors

The deposition pattern or “linewidth” of an inertial particle deposit from acceleration of an aerosol through a high aspect ratio slit nozzle-substrate system is influenced by particle size-dependent aerodynamic focusing. In addition to this, high aspect ratio jets will eventually undergo downstream “jet-axis switching”, wherein the jet profile shrinks along its major axis and elongates in the direction of the minor axis. Jet axis switching in an aerosol may also lead to “rotated” particle deposits. In this study, we use a converging–diverging slit nozzle system with a major axis length of 8 mm and a throat width (minor axis) of 200 μm to examine the deposition patterns of monodisperse particles in the 100 nm–5 μm diameter range, in air with an upstream pressure of 252 Torr and variable downstream pressure in the 3–50 Torr range. The nozzle-to-substrate distance L∗ is varied from 90 to 248 times longer than the throat width. We find deposition patterns that are strongly dependent on particle size, downstream pressure, and L∗. Depending on particle diameter and operating conditions, we obtain deposits resembling the nozzle dimensions and orientation, deposits which are completely switched (perpendicular to the nozzle), or deposits which are relatively symmetric and focused at a center point. The latter appear to be the result of the combined effects of jet axis switching and aerodynamic focusing. In general, the influence of jet axis switching is more pronounced on smaller particles at higher downstream pressures, and with larger distances to the substrate. The extent of switching and area of the deposit are also both inversely related to the particle Stokes number.

Three-dimensional internal flow evolution of an evaporating droplet and its role in particle deposition pattern

The internal flow within an evaporating sessile droplet is one of the driving mechanisms that lead to various particle deposition patterns seen in applications such as inkjet printing, surface patterning, and blood stain analysis. Despite decades of research, the causal link between droplet internal flow and particle deposition patterns has not been fully established. In this study, we employ a three-dimensional (3D) imaging technique based on digital inline holography to quantitatively assess the evolution of internal flow fields and particle migration in three distinct types of wetting droplets, namely water droplets, sucrose aqueous solution droplets, and sodium dodecylsulfate aqueous solution droplets, throughout their entire evaporation process. Our imaging reveals the three-stage evolution of the 3D internal flow regimes driven by changes in the relative importance of capillary flow, Marangoni flow, and droplet boundary movement during evaporation. Moreover, the migration of individual particles from their initial locations to deposition can be divided into five categories, with some particles depositing at the contact line and others inside the droplet. In particular, we observe the changing migration directions of particles due to competing Marangoni and capillary flows. We further develop an analytical model that predicts the droplet internal flow, deposition patterns, and determines the deposition mechanisms depending on their initial locations and evolving internal flow. The model, validated using different types of droplets from our experiment and the literature, can be further expanded to other Newtonian and non-Newtonian droplets, potentially serving as a real-time assessment tool for particle deposition in various applications.

Characteristics of Soil Particle Sizes and Fractal Parameters under Different Plantation Types of Populus alba

Vegetation plays a leading role in restoring desert ecosystems and increasing productivity. In this study, we elucidate the improvement effects of different restoration areas of Populus alba on the soil particle distribution, sedimentation environment, and fractal characteristics. We selected the restoration areas of P. alba × Caragana korshinskii (YN), P. alba × Hedysarum leave (YY), and P. alba × Hedysarum scoparium (YH), which have a history of twenty-one years. We analyzed the soil nutrients, soil particle size, soil particle size parameters, soil fractal dimension (D) values, and soil multifractal parameters at soil depths of 0–80 cm. We found that the YN, YY, and YH significantly increased the soil nutrients and soil fine particles (p < 0.05) and changed the deposition pattern of the soil particles in the sandy area. The YN, YY, and YH promote soil particle refinement and reduce the sorting performance of the soil particles. The vegetation promotes extremely positive-skewed and very leptokurtic soil particle distributions. The D values in the YN, YY, and YH restoration areas increased by 7.62%–27.94%, 7.36%–26.28%, and 7.10%–17.92%, respectively, relative to those of the LS. The construction of the different restoration areas of P. alba has made the distribution of the soil particles nonuniform. Compared with the YY and YH plantations, the distribution range of the soil particles in the YN plantation is wider, and the distribution heterogeneity is greater. In addition, we found that the fractal parameters are influenced by the soil physicochemical properties, the depositional environment, and vegetation factors. Therefore, we believe that D values and multifractal parameters are necessary as additional information for desert soil texture improvement. The results of this study provide a scientific and theoretical basis for the future revegetation of deserts.

Simulation of particle deposition on solar photovoltaic panels based on a new critical capture velocity criterion

Solar energy, as a clean energy source, is becoming increasingly important in the global energy mix. However, particle deposition on the surface of photovoltaic (PV) panels can significantly reduce their power generation efficiency. In this study, the collision-deposition behaviour between silica particles and the surface of PV modules is investigated. The impact process of 13 μm silica particles on the glass surface was recorded by using a high-speed digital camera at various incident velocities and angles. A particle dynamics model was developed to predict the critical capture velocity of particles at different incident angles. It was observed that the critical capture velocity of the particles decreases as the angle of incidence increases. Subsequently, a correlation equation was established between the incident angle and the critical capture velocity, serving as the deposition criterion. Computational Fluid Dynamics (CFD) numerical simulation was employed to simulate particle deposition on PV surfaces under different wind speeds and installation tilting angles. The simulation results demonstrate that the mass of 13 μm silica particles deposited on the surface of PV panels decreases with increasing wind speed. Moreover, under identical inlet wind speeds, the particle deposition mass exhibits an initial decrease followed by a subsequent increase as the installation tilt angle of the PV panel increases. The distribution pattern of particle deposition on PV panel surfaces is diverse; however, predominantly concentrated at the mid-bottom region.

LOCATE v1.0: numerical modelling of floating marine debris dispersion in coastal regions using Parcels v2.4.2

Abstract. The transport mechanisms of floating marine debris in coastal zones remain poorly understood due to complex geometries and the influence of coastal processes, posing difficulties in incorporating them into Lagrangian numerical models. The numerical model LOCATE overcomes these challenges by coupling Eulerian hydrodynamic data at varying resolutions within nested grids using Parcels, a Lagrangian particle solver, to accurately simulate the motion of plastic particles where a high spatial coverage and resolution are required to resolve coastal processes. Nested grids performed better than a coarse-resolution grid when analysing the model's dispersion skill by comparing drifter data and simulated trajectories. A sensitivity analysis of different beaching conditions comparing spatiotemporal beaching patterns demonstrated notable differences in the land–water boundary detection between nested hydrodynamic grids and high-resolution shoreline data. The latter formed the basis for a beaching module that parameterised beaching by calculating the particle distance to the shore during the simulation. A realistic debris discharge scenario comparison around the Barcelona coastline using the distance-based beaching module in conjunction with nested grids or a coarse-resolution grid revealed very high levels of particle beaching (>91.5%) in each case, demonstrating the importance of appropriately parameterising beaching at coastal scales. In this scenario, high variability in particle residence times and beaching patterns was observed between simulations. These differences derived from how each option resolved the shoreline, with particle residence times being much higher in areas of intricate shoreline configurations when using nested grids, thus resolving complex structures that were undetectable using the coarse-resolution grid. LOCATE can effectively integrate high-resolution hydrodynamic data within nested grids to model the dispersion and deposition patterns of particles at coastal scales using high-resolution shoreline data for shoreline detection uniformity.

Enhancing Inhalation Drug Delivery: A Comparative Study and Design Optimization of a Novel Valved Holding Chamber.

This paper presents an innovative approach to the design optimization of valved holding chambers (VHCs), crucial devices for aerosol drug delivery. We present the design of an optimal cylindrical VHC body and introduce a novel valve based on particle impaction theory. The research combines computational simulations and physical experiments to assess the performance of various VHCs, with a special focus on the deposition patterns of medication particles within these devices. The methodology incorporates both experimental and simulation approaches to validate the reliability of the simulation. Emphasis is placed on the deposition patterns observed on the VHC walls and the classification of fine and large particles for salbutamol sulfate particles. The study reveals the superior efficacy of our valve design in separating particles compared to commercially available VHCs. In standard conditions, our valve design allows over 95% of particles under 7 μm to pass through while effectively filtering those larger than 8 μm. The optimized body design accomplishes a 60% particle mass flow fraction at the outlet and an average particle size reduction of 58.5%. When compared numerically in terms of size reduction, the optimal design outperforms the two commercially available VHCs selected. This study provides valuable insights into the optimization of VHC design, offering significant potential for improved aerosol drug delivery. Our findings demonstrate a new path forward for future studies, aiming to further optimize the design and performance of VHCs for enhanced pulmonary drug delivery.

Comparison of microparticle transport and deposition in nasal cavity of three different age groups

Objective: The nasal cavity effectively captures the particles present in inhaled air, thereby preventing harmful and toxic pollutants from reaching the lungs. This filtering ability of the nasal cavity can be effectively utilized for targeted nasal drug delivery applications. This study aims to understand the particle deposition patterns in three age groups: neonate, infant, and adult. Materials and methods: The CT scans are built using MIMICS 21.0, followed by CATIA V6 to generate a patient-specific airway model. Fluid flow is simulated using ANSYS FLUENT 2021 R2. Spherical monodisperse microparticles ranging from 2 to 60 µm and a density of 1100 kg/m3 are simulated at steady-state and sedentary inspiration conditions. Results: The highest nasal valve depositions for the neonate are 25% for 20 µm, for infants, 10% for 50 µm, 15% for adults, and 15% for 15 µm. At mid nasal region, deposition of 15% for 20 µm is observed for infant and 8% for neonate and adult nasal cavities at a particle size of 10 and 20 µm, respectively. The highest particle deposition at the olfactory region is about 2.7% for the adult nasal cavity for 20 µm, and it is <1% for neonate and infant nasal cavities. Discussion and conclusions: The study of preferred nasal depositions during natural sedentary breathing conditions is utilized to determine the size that allows medication particles to be targeted to specific nose regions.

Study on the Effects of Dust Particle Size and Respiratory Intensity on the Pattern of Respiratory Particle Deposition in Humans

Nowadays, dust exposure pollution is receiving a lot of attention due to its significant impact on public health. To investigate the impact of dust particle size and human respiratory strength on respiratory particle deposition patterns, data was collected through on‐site surveys. The study analyzed the equivalent respiratory strength, dust environment characteristics, and bronchial particle escape and deposition patterns of humans in fully mechanized mining faces at various operating times. This was done using ergonomic energy consumption simulation experiments and a fluid–solid interaction method of CFD‐DEM. The findings revealed that as humans worked continuously for 5, 15, 30, 45, and 60 min, their respiratory intensity corresponded to 8, 18, 30, 42, and 50 L/min, respectively. According to the field investigation and particle size analysis, the particle size distribution of 1~5, 5~10, 10~20, 20~30, and 30~40 μm particles accounted for 36%, 26%, 15%, 11%, and 10%, respectively. In general, the deposition rate of dust was highest in the main bronchus of the respiratory tract, followed by the trachea area. Particles ranging from 5 to 10 μm in size were observed to have a higher likelihood of escaping from the tertiary bronchioles and entering the secondary bronchial regions. Conversely, particles larger than 20 μm exhibited a deposition rate of up to 80% in the tertiary bronchial regions. It was noted that the bronchial deposition rate of particles of varying sizes increased with respiratory strength, with smaller particles showing greater sensitivity to changes in respiratory strength in terms of the deposition fraction. Among the different particle sizes, the deposition rate of 5–10 μm particles exhibited the most variation with increasing respiration intensity, ranging up to 17%.

Effect of microplastics deposition on human lung airways: A review with computational benefits and challenges

Microplastics have become omnipresent in the environment, including the air we inhale, the water we consume, and the food we eat. Despite limited research, the accumulation of microplastics within the human respiratory system has garnered considerable interest because of its potential implications for health. This review offers a comprehensive examination of the impacts stemming from the accumulation of microplastics on human lung airways and explores the computational benefits and challenges associated with studying this phenomenon. The existence of microplastics in the respiratory system can lead to a range of adverse effects. Research has indicated that microplastics can induce inflammation, oxidative stress, and impaired lung function. Furthermore, the small size of microplastics allows them to penetrate deep into the lungs, reaching the alveoli, where gas exchange takes place. This raises concerns about long-term health consequences, such as the development of respiratory diseases and the potential for translocation to other organs. Computational approaches have been instrumental in understanding the impact of microplastic deposition on human lung airways. Computational models and simulations enable the investigation of particle dynamics, deposition patterns, and interaction mechanisms at various levels of complexity. However, studying microplastics in the lung airways using computational methods presents several challenges. The complex anatomy and physiological processes of the respiratory system require accurate representation in computational models. Obtaining relevant data for model validation and parameterization remains a significant hurdle. Additionally, the diverse nature of microplastics, including variations in size, shape, and chemical composition, poses challenges in capturing their full range of behaviours and potential toxicological effects.

Microgel particle deposition patterns after impinging on nanofiber-based coatings

The study focuses on predicting the hydrodynamics of sodium alginate-based microgel “liquid core–gel shell” particles for droplet-based bioprinting. Hydrophobic polytetrafluoroethylene nanofiber-based coating (NBC #1) and hydrophilic polycaprolactone–polyvinylpyrrolidone NBC #2 are manufactured to serve as the basis for microgel deposition. An approach is proposed to model the flow of a Maxwell gel-like liquid with different fluidity, surface tension, and initial velocity along an inhomogeneous interface after microgel particle–NBC collision. Wetting and anti-wetting pressure differences allow estimating liquid impalement into NBCs at We = 10–50. For NBC #2, the initial particle velocity plays mainly a decisive role in predicting the contact diameter and height at maximum spreading and receding. For NBC #1, the pinning is considered by introducing the complex parameter resolving particle inertia, microgel rheology and surface tension, and NBC characteristics. The flow along the porous interface physically correlates with the extended Freundlich model, explaining the surface inhomogeneity caused by multilayer adsorption.