Particle Impact Research Articles

Fibrous‐biocomposites scaffold of natural rubber with bioactive glass–ceramic particles obtained by solution blowing spinning

AbstractBioactive glass‐ceramics (BGs) are widely used in clinical applications due to their excellent biodynamic and biological properties, though their low mechanical strength limits their use in load‐bearing contexts. This study aimed to develop fibrous biocomposite scaffolds based on natural rubber (NR) reinforced with BG particles, such as biosilicato (BioS) and 45S5‐K (BL0), to improve tensile strength, biocompatibility, and bioactivity for biomedical applications, such as tissue engineering. Morphological, tensile, thermal, and biological tests were conducted to evaluate the impact of BG particles on the NR fibrous matrix. TG/DTG analysis revealed similar decomposition profiles for NR/BioS and NR/BL0 biocomposites compared to NR mats, with primary degradation occurring in the 290–450°C range. Tensile tests demonstrated that the addition of 30 mass% BioS or BL0 enhanced the ultimate tensile strength (σbreak) of the NR matrix from 1.44 ± 0.08 to 3.38 ± 1.31 MPa (NR/BioS) and 1.97 ± 0.53 MPa (NR/BL0). The Cole–Cole plot indicated system heterogeneity and strong NR‐BG particle interactions. Cytotoxicity tests revealed over 70% MSC viability for NR, NR/BioS, and NR/BL0 biocomposites, meeting ISO 10993‐5:2009 standards. These findings suggest that incorporating BioS and BL0 enhances the mechanical and biological properties of NR‐based scaffolds, making them suitable for biomedical applications, such as bone regeneration.

Excitation of Helium by Proton and Antiproton Impact

The electron transitions in atoms caused by charged particle impact are benchmarks for the study of electron dynamics. In the present paper we focus on the excitation of helium by proton and antiproton impact. We perform both ab initio and perturbational calculations, revealing the importance of electron correlations and higher-order effects. The influence of the projectile charge sign on the excitation cross section is also studied.

Direct numerical simulation of turbulent flow and heat transfer in a particle-laden turbulent channel flow

Direct numerical simulation (DNS) is conducted to investigate the impact of solid particles on heat transfer in a plane channel flow. For comparison, two corresponding DNSs of unladen channel flow are also performed. The numerical simulation of the particle-laden case employs a two-way coupled Eulerian–Lagrangian computational model, which allows for the consideration of momentum transfer between the two phases: discrete particles and the continuous fluid phase. The presence of particles results in an increase in the mean temperature, the root mean square (rms) of temperature fluctuations, and the streamwise turbulent heat flux within the core region. Furthermore, particles exert a more significant influence on these characteristics at higher solid volume fractions. Additionally, the correlation between velocity and temperature is affected by the presence of particles. When comparing heat transfer in particle-laden channel flow to that in the corresponding unladen channel flow, it is observed that the difference in heat flux arises from changes in the rms of the wall-normal velocity and temperature fluctuations. The impact of particles on turbulent heat flux transport is significant in the vicinity of the wall, while their influence within the core region is relatively small.

The Influence of Fibers from Domestic Laundry Wastewater on the Clogging Process of a Filter

This study presents the impact of the size and shape of particles in laundry wastewater on the clogging process of a porous material. Clogging can be defined as a mechanical limitation of flow through porous media. The process of mechanical clogging was investigated in this study. The research was conducted in laboratory conditions in a filter column filled with glass beads whose diameter corresponded to coarse sand. The results reveal the influence of graywater quality on filter hydraulic conductivity and bed clogging, showing the impact of fiber particles in wastewater (sewage from home laundry) on the clogging process in soil. The results confirm that fiber particles significantly reduce filter permeability, particularly due to the formation of a filter cake. As analyzed in this paper, the distribution of quantitative data on particles of different sizes found in laundry wastewater indicates that they mainly accumulate in the upper layer, where particles with fiber lengths ranging from 0 to 1600 µm can be found. The average length of the fibers decreased with increasing depth. At a depth of approximately 10 cm, fibers with dimensions in the range of 0 to 100 μm were predominantly observed.

Effect of SiC particles on microstructure and mechanical properties of SiCp/AZ91 magnesium matrix composite brazed joint

The impact of SiC particles on the microstructure, mechanical properties, and fracture morphology of magnesium alloy brazed joints was investigated. The brazing experiments of AZ91+AZ91, AZ91+SiCp/AZ91, and SiCp/AZ91+SiCp/AZ91 were carried out under the same technological conditions by using the self-designed special filler metal for magnesium matrix composites. The impact of SiC particles on the microstructure and mechanical properties of brazed joints was analyzed. The addition of Ti can effectively enhance the wettability of filler metal on SiC particles. The shear strength of SiCp/AZ91+SiCp/AZ91 joints is 76.0MPa. The shear strength of the joint is 43.4% higher than that of AZ91+ AZ91.

Biotoxicity Evaluation of Biodegradable Polymeric Particles: Exploring the Possible Adverse Impacts on Biological Systems

ABSTRACTThis study aimed to investigate the impact of plastic particles on cell viability and tissue toxicity. The cells were subjected to incubation with plastic particles immobilized in agar gels, resulting in minimal cell death and cytotoxicity. Furthermore, direct exposure of various cell types to suspended plastic particles showed negligible effects on cell viability, with no observed lysis or growth inhibition. Staining techniques revealed minimal plastic particle‐induced cell death, with the majority of cells remaining viable. However, histological evaluations of mouse tissues demonstrated that the nondegradable low‐density poly(ethylene) (LDPE) groups exhibited severe irritation, characterized by an excessive presence of macrophages, neutrophils, fibrosis, fat infiltration, and increased blood vessel formation in subcutaneous tissue. In contrast, biodegradable neat poly(butylene succinate) (KRICT‐PBS) and cellulose nanocrystals/PBS nanocomposite (CNC‐PBS) groups induced minimal toxicity. Interestingly, the intravenous injection of KRICT‐PBS and CNC‐PBS degradate solutions in mice exhibited mild toxicity, suggesting no significant damage to normal kidney and liver function.

A numerical investigation of heat transfer and clogging in smooth and ribbed cooling channels of the GEF9’s first rotor blade

Analysis of heat transfer and the possibility of clogging in gas turbines play a crucial role in their design and material selection. Due to the high operating temperatures of gas turbine blades, internal blade cooling is utilized to reduce the damage of high temperatures and enhance the durability of gas turbines. Among these methods, the blades' internal cooling is one of the most common approaches. The main objective of this research is to investigate the feasibility of using ribs to increase the internal cooling rate and consequently reduce the surface temperature of the second rotor blade of the GEF9 turbine. Additionally, the experimental observations of damaged blades, proved that some of the internal cooling paths are blocked due to particle deposition of dusty cooling air. So, the main innovation of this research lies in simulating the dust trajectory of dust particles within the cooling channels using an Eulerian-Lagrangian approach to predict blockages in the cooling channels, as well as investigating erosion resulting from the impact of dust particles with the cooling passage walls. Based on the obtained results, ribs increase the convective heat transfer up to 40% but raise the pressure drop in other hands. With analysis of different types of geometrical parameters, the best thermal efficiency is about 0.76 (less than 1). The probability of clogging in the ribbed channels is 100 times more than smooth ones and also the rate of erosion in ribbed channels is 10% more than smooth channels which can increase the stress and reduce the durability of the blade. So using rib in this type of blade is not feasible. By comparing the volume fractions of dust particles near the internal walls in the smooth cooling channels, the first and fourth channels have the highest and lowest likelihood of blockages, respectively and it shows that front channels should be designed with higher diameter.

Analysis and mitigation of erosion wear of transfer ducts in a falling particle CSP system

Solid particles are effective heat capture and transfer media for next-generation (Gen3) concentrating solar power (CSP) plants that offer high-temperature operability, lower levelized cost, and higher efficiency. However, the relative motion of the solid particles with respect to the CSP system components causes significant wear of the wall materials in the form of erosion and abrasion. The transfer duct is one of the prevalent components in the falling particle CSP system that experiences erosion wear due to the impact of particles on its surface, which depends on several factors, such as duct design, material, and particle flow rate, among others. In this work, erosion wear in the transfer duct and its mitigation were studied computationally through different duct designs and particle flow parameters, including transfer duct length, diameter, slanted angle of the duct, and entrance velocity. Computational simulations based on particle tracking and discrete element modeling were used to understand erosion behavior systematically and, in turn, identify areas most prone to erosive wear. It was found that the use of erosion-resistant coatings in selected locations determined from the simulations was sufficient to mitigate overall erosion wear in the component. This study provides fundamental insight into the erosion wear of a key component of the falling particle CSP system for the first time and the design approaches to mitigate wear.

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 Study of Particle Impingement on Aeroengine under Mixed-Phase Conditions

In this approach, considering to ice crystal sticking effects, a numerical model was established to solve the particle impingement property of a large bypass ratio aeroengine under mixed-phase icing conditions. The collection efficiency of droplets obtained by the proposed model is are well in agreement with the literature and the collection efficiency of ice crystals is significantly higher than that of droplets due to the greater inertial force. The mechanism of liquid film acting on the ice crystal adhesion affect was investigated. It is found that the greater melt ratio can lead to more sufficient liquid water and more extended wetting limit, which have more significant capability of sticking ice crystals. Meanwhile, due to ice crystals subjected to centrifugal force, the sticking coefficient of ice crystal will cliff-like drop, and the cliff-like effect is more pronounced accompanied by the greater centrifugal force.

Investigating the Performance of Glass Fibre-Reinforced Polymer (GFRP) in the Marine Environment for Tidal Energy: Velocity, Particle Size, Impact Angle and Exposure Time Effects

Tidal energy, with its potential to provide a consistent energy output and reduce carbon emissions, has garnered significant interest. This study, which evaluates the performance of tidal turbine blades in seawater conditions and with sand particles, presents a novel approach. A slurry rig was developed to examine composite materials, and a glass fibre-reinforcement polymeric material was tested over a range of particle sizes, velocities, and impact angles. In addition, this paper used a new test protocol with 14 days (336 h) and 91 days (2184 h) of pre-exposure time of materials before testing. The results, which show significant changes in the erosive mechanisms of GFRP in short- and long-term pre-exposure time as a function of these variables, have profound implications for the design and performance of tidal turbine blades. The study also utilised scanning electron microscopy (SEM), depth profiling analysis, and erosion mapping techniques to compare the erosion behaviours of GFRP. These tools can be used to optimise such materials in tidal turbine conditions.

Analysis of Erosion of Surfaces in Falling Particle Concentrating Solar Power

Abstract Next generation concentrating solar power (CSP) systems, which utilize solid particles for energy capture, transport, and storage, offer prospects for higher temperature operation, improved efficiency, and reduced overall costs. Nevertheless, the continuous impingement of particles on component materials can result in substantial erosion, significantly constraining the performance and longevity of the components. A comprehensive understanding of particle erosion on surfaces is essential for designing components and operational parameters or coatings that minimize wear. This study presents a computational physics-based particle tracking model of the erosion rate of incident surfaces under different geometric, operational, and particle parameters. The computational model is validated with experimental measurements conducted as part of the study. Computational simulations are presented to elucidate the effects of each parameter and further used to investigate erosion rates in a systematic design of experiments covering a wide range of parameters. Based on the simulation results, a generalized analytical model is developed to relate erosion wear to pertinent dimensionless groups governing the physics of the process. The analytical model is shown to be accurate to within 10% and its use in understanding surface erosion as well as designing wear-resistant coatings to limit erosion within acceptable values is presented.

Effect of Laser on the Interface and Thermal Conductivity of Metallized Diamond/Cu Composite Coatings Deposited by Supersonic Laser Deposition.

To achieve the rapid heat dissipation of components in the industrial field, the heat dissipation coating is prepared on the surface, which is conducive to improving the service life of the parts and greatly reducing the industrial costs. In this paper, metallized diamond/Cu composite coatings were fabricated on 1060Al substrate by supersonic laser deposition. The composite coatings were prepared at a nitrogen pressure of 3.0 MPa, a scanning speed of 10 mm/s, and a 1060 nm semiconductor coupled fiber laser with different laser power. The research results show that the laser power affects the interface bonding by affecting the temperature of adiabatic shear instability during particle impact. The metallized diamond forms a good bonding at the interface through the plastic deformation of the Cu matrix. Appropriate parameters ensure that the jet does not affect the subsequent particle deposition and build a good heat transfer bridge to elevate the heat transfer efficiency. The coating prepared at a laser power of 1000 W has the highest thermal diffusion coefficient of 89.3 mm2/s and thermal conductivity of 313.72 W/(m·K), which is 8.92% higher compared to the coating prepared without laser. Experiments with thermal imaging have also demonstrated that the coating at optimal parameter transferred heat faster. Our research provides a technical guidance for rapid preparation of high-quality heat dissipation coatings in industry.

Spaceborne COTS-Capsule hodoscope: Detecting and characterizing particle radiation

The COTS-Capsule Spaceborne hodoscope was launched into low Earth orbit aboard the International Space Station and operated from 2021 to 2022. The primary objectives of the payload are measuring and characterizing the radiation environment within the space station, serving as a technology demonstrator for the COTS-Capsule radiation mitigation apparatus, and testing the interaction of high-energy cosmic particles on-orbit with our detectors. The payload features a particle hodoscope equipped with an array of novel detectors based on polyvinyl toluene scintillators and silicon photomultiplier sensors that are used for radiation detection and characterization employing 2D intensity-based triangulation. This paper provides a comprehensive account of the COTS-Capsule payload’s construction, preflight performance, testing, qualification, and on-orbit calibration. The hodoscope, sensitive to ionizing cosmic particles, facilitates impinging particle track reconstruction by multi-detector 2D position estimation, energy deposition estimation, and linear energy transfer estimation.

Loose particle Detection: The optimal detection condition and weak loose particle impulse extraction

To achieve effective detection of loose particles within small cavities in microelectronic devices, this paper proposes the optimal detection conditions of loose particles in ceramic packaging for microelectronic devices based on simulation, and presents a method for weak signal reconstruction using weighted sparse representation. To address the challenge of ineffective detection of loose particles under recommended vibration conditions, a particle-cavity collision dynamics model is established. Subsequently, the detection laws of loose particles under different accelerations, frequencies, and cavity heights are studied through simulation, leading to the establishment of optimal detection conditions for microelectronic devices with varying cavity heights. To address the issue of weak impulses being submerged in background noise under optimal detection conditions, sparse representation is utilized for signal reconstruction. First, a Laplace wavelet dictionary is constructed according to the impulse characteristics. Second, the generalized minimax-concave (GMC) penalty function is applied as a sparse regularization term to preserve signal amplitude. Meanwhile, a weight matrix based on kurtosis and singular value is designed to threshold sparse coefficients. The results demonstrate that the proposed optimal detection conditions and signal reconstruction method effectively detect loose particles. Compared with other algorithms, the proposed method reduces background noise in the particle impact noise detection (PIND) signals while maintaining impulse amplitude; it also improves signal reconstruction accuracy and offers valuable insights into effective loose particle detection in microelectronic packaging devices.

Shape of fragments cloud behind heterogeneous screen by a space debris particle impact

Technogenic pollution of near-Earth space poses a threat to the functioning of spacecraft. Collisions between space debris (SD) and spacecraft (SC) structures can have catastrophic consequences or cause localized damage, leading to the loss of SC operability or the failure of certain functions. The SC body must effectively protect the internal equipment from various external impacts, be technologically feasible to manufacture, and have as little mass as possible. As a result, the task of designing spacecraft bodies and protective screens for low-orbit SC is particularly relevant due to the large concentration of SD in low Earth orbits.A comparative numerical study was conducted to evaluate the effectiveness of various thin shields in protecting against impacts from space debris particles. The study examined homogeneous shields made of A356 aluminum alloy and 316L stainless steel, as well as volumetrically reinforced composite shields produced using additive manufacturing with steel inclusions, and shields with a gradient distribution of steel throughout the thickness of an aluminum matrix, all with the same areal density. In all the heterogeneous plates considered, the volumetric concentration of steel was 36 %. The study covered an interaction velocity range of 2–9 km/s. Numerical modeling results indicated that the structure of the thin heterogeneous plate does not affect the shape of the debris cloud formed behind the protective shield. The findings of this study can serve as a basis for selecting materials for the development of more effective protection for spacecraft against high-velocity impacts.

Solidification behavior of WC particles reinforced nickel alloy cladding layers by plasma surfacing: Simulation and experiment

In this work, a numerical simulation model was developed to investigate the complex heat and mass transfer process inside the molten pool during plasma surfacing. The temperature distribution and fluid flow were employed to depict the evolution of the molten pool. The findings revealed that the maximum temperature is located on the surface of the cladding layer corresponding to the position of heat source, and the temperature distribution follows a Gaussian distribution along the scanning direction. Thermal accumulation is obvious due to the continuous energy input in the initial stage, as a result, the maximum temperature and fluid flow velocity gradually increase with the deposition process. The maximum temperature and fluid flow velocity at 4.0 s are 1893 K and 0.281 m/s in case 110 A, respectively. The predicted shapes and dimensions are consistent with the results of the deposition experiments, with a maximum error of no more than 15 %. In order to investigate the impact of WC particles on the solidification microstructure of nickel composite layers, corresponding plasma surfacing experiment was implemented. The solidification characteristics of the microstructure follow planar-cellular-columnar-equiaxed crystals in the bonding layer and WC particles-columnar-equiaxed dendritic crystals in hard layer, respectively. Furthermore, the Ni dendritic near the retained WC particles transformed into columnar crystals due to temperature gradient in the local area.

On the Role of Substrate in Hydroxyapatite Coating Formation by Cold Spray

The deposition of agglomerated hydroxyapatite (HAp) powders by low-pressure cold spray has been a topic of interest in recent years. Key parameters influencing the deposition of HAp powders include particle morphology and impact kinetic energy. This work examines the deposition of HAp powders on various metal surfaces to assess the impact of substrate properties on the formation of HAp deposits via cold spray. The substrates studied here encompass metals with varying hardness and thermal conductivities, including Al6061, Inconel alloy 625, AISI 316 stainless steel, H13 tool steel, Ti6Al4V, and AZ31 alloy. Single-track experiments offer insights into the initial interactions between HAp particles and different substrate surfaces. In this study, the results indicate that the ductility of the substrate may enhance HAp particle deposition only at the first deposition stages where substrate/particle interaction is the most critical factor for deposition. Features on the substrate associated with the first deposition sprayed layer include localized substrate deformation and the formation of clusters of HAp agglomerates, which aid in HAp deposition. Furthermore, after multiple spraying passes on the various metallic surfaces, deposition efficiency was significantly reduced when the build-up process of HAp coatings shifted from ceramic/metal to ceramic/ceramic interactions. Overall, this study achieved agglomerated HAp deposits with high deposition efficiencies (30–60%) through single-track experiments and resulted in the preparation of HAp coatings on various substrates with thickness values ranging from 24 to 53 µm. These coatings exhibited bioactive behavior in simulated body fluid.

Numerical Investigation of Erosion in Pipeline Bends Using CFD Simulation

Erosion in pipeline bends is a significant issue in various industrial applications, particularly in oil and gas transportation systems. This study presents a numerical investigation of erosion in pipeline bends using Computational Fluid Dynamics (CFD) simulation. The primary focus is to predict erosion rates and identify erosion-prone areas based on different flow conditions, particle properties, and bend geometries. A multiphase flow model incorporating Eulerian-Lagrangian approaches was used to simulate the interaction between fluid and solid particles. The erosion rates were evaluated using empirical models that relate particle impact characteristics, such as velocity and angle of impingement, to material degradation. Simulations were conducted for various particle sizes, velocities, and flow rates, allowing for a comprehensive analysis of erosion patterns. Results indicate that erosion is concentrated on the outer walls of the bend, with higher particle velocities exacerbating material wear. Additionally, increasing particle size and flow velocity significantly influence the erosion rates. The findings of this study provide valuable insights into optimizing pipeline design and flow conditions to mitigate erosion, thereby extending the lifespan of pipeline systems in industrial applications.

Scintillator-SiPM detector for tracking and energy deposition measurements

An innovative particle detector that offers a compelling combination of cost-effectiveness and high accuracy is introduced. The detector features plastic scintillators paired with a sparse arrangement of SiPMs, strategically positioned within a unique opto-mechanical framework. This configuration delivers precise measurements of spatial impact position and energy deposition of impinging particles. The manuscript describes the detector’s physical model complemented by an analytical representation. These calculations underpin a numerical algorithm, facilitating the estimation of particle impingement position and energy deposition. The results of the numerical calculations are compared with the output of GEANT4 simulations and evaluated by rigorous laboratory testing. An array of these detectors, intended for deployment in a spaceborne experiment, underwent detailed design, manufacturing, and testing. Their performance and alignment with the physical model were validated through meticulously conducted ground-based laboratory experiments, conclusively affirming the detector’s properties.