Characterization Of Particles Research Articles

Enhanced catalytic degradation of methylene blue using self-propelled Janus micromotors: An insight into decomposing characteristics of passive and active hematite particles studded with Pt nanoparticles.

Recent advancements in catalytic micromotors have shown significant potential for environmental applications, yet challenges such as particle agglomeration persist. In this study, we compare the degradation of methylene blue using hematite particles fully coated with platinum and those partially decorated with platinum. The selective decoration, confirmed through techniques like EDX, FESEM, TEM, and XPS, plays a crucial role in the micromotors' behavior. The decomposition of hydrogen peroxide (H2O2) by Pt nanoparticles on one side of the hematite particles generates thrust, propelling the micromotors and enhancing their interaction with pollutant molecules. This active mobility helps counteract agglomeration, preventing the formation of irregular 3D clusters and improving catalytic efficiency. Our findings show that partially decorated particles achieve up to 85% dye removal within 90min, outperforming fully decorated particles, which reach only 33% efficiency due to aggregation and sedimentation. These results underscore the importance of optimized surface decoration for improving the performance and stability of catalytic systems in pollutant degradation.

Biosintesis Nanopartikel Seng Oksida dengan Ekstrak Limbah Kulit Pisang Tanduk (Musa paradisiaca fa. corniculata)

The high amount of banana consumption in Indonesia has caused banana peel waste to increase, which can cause environmental pollution. One of the utilization of banana peel waste is as a metal nanoparticle synthesis. This study aims to synthesize ZnO nanoparticles with banana peel extract as a capping agent and determine the effect of solvent volume variation on the characterization of ZnO particles using variable volume of ethanol-water solvent with a ratio of 2:1 and 1:1 (v/v). This research uses maceration extraction method for 24 hours. Characterization of ZnO particles was carried out including Fourier Transform Infrared Spectroscopy (FTIR) and Particle Size Analyzer (PSA). In this study, the total polyphenol and flavonoid content in ethanol - water 1:1 (v/v) horn banana peel extract was higher at 4.944% and 5.940% than ethanol - water 2:1 (v/v) at 4.114% and 4.131%. Based on the results of FTIR testing, both samples have ZnO peaks where in ethanol - water 1:1 (v/v), 441 cm-1 and 619 cm-1, while ethanol - water 2:1 (v/v) is 428 cm-1. Then, from the PSA test results, the ethanol-water 1:1 (v/v) sample has a smaller average nanoparticle diameter of 135.6 nm than the ethanol-water 2:1 (v/v) sample which is 153.6 nm. ZnO nanoparticles were successfully synthesized using the natural capping agent banana peel extract. Different levels of secondary metabolites in each extract have an influence on the diameter of the synthesized ZnO nanoparticles.

Role of obstacle softness in the diffusive behavior of active particles.

We numerically investigate the diffusive behavior of active Brownian particles in a two-dimensional confined channel filled with soft obstacles, whose softness is controlled by a parameter K. Here, active particles are subjected to an external bias F. Particle diffusion is influenced by entropic barriers that arise due to variations in the shape of the chosen channel geometry. We observed that the interplay between obstacle softness, entropic barriers, and external bias leads to striking transport characteristics of the active particles. For instance, with increasing F, the non-linear mobility exhibits a non-monotonic behavior, and effective diffusion is greatly enhanced, showing multiple peaks in the presence of soft obstacles. Furthermore, as a function of K and F, particles exhibit various diffusive behaviors, e.g., normal diffusion-where the role of obstacles is insignificant, and subdiffusion or superdiffusion-where the particles are partially trapped by the obstacles, and the particles are ultimately caged by the obstacles. These findings help understand the physical situations wherein active agents diffuse in crowded environments.

Ultrasonic cavitation finishing of 316 L stainless steel using different abrasive particles: A combined SPH simulation and experimental study

Ultrasonic cavitation and its driving effect on abrasive particles have been studied and applied to the surface finishing of 316 L stainless steel. To explore the influence of abrasive characteristic parameters on the surface finishing process, a cavitation-driven single abrasive impact model was established by coupling the smoothed particle hydrodynamics (SPH) method with the finite element method (FEM). The changes in the workpiece surface and the wear of abrasive particles after the impact were analysed, the effects of the abrasive particle size, material and shape were discussed, and the effectiveness of the model was verified through ultrasonic finishing experiments. SiC abrasive particles possessing irregular shape and Al2O3 abrasive particles possessing irregular and spherical shapes were used for comparison. Both simulation and experimental results indicate that the abrasive particle with a high hardness and a spherical shape has better material removal capability. However, the spherical abrasive particles tended to occur large cracks and split into small pieces, which accelerated the wear of the abrasives. In this work, the best finishing result was obtained by using irregularly shaped SiC abrasive particles, and the surface roughness Ra was improved by 12.87 %. This study provides a comprehensive understanding of the material removal process using cavitation-driven abrasives and examines the influence of key characteristics of abrasive particles. These insights are significant for advancing the application and enhancement of this technology in metal surface treatment.

Migration and Deposition Characteristics of Sand Particles on Mesh Filter Surfaces in Water-Saving Irrigation Systems: Evidence from Simulation and Experimental Verification

Migration and Deposition Characteristics of Sand Particles on Mesh Filter Surfaces in Water-Saving Irrigation Systems: Evidence from Simulation and Experimental Verification

Experimental study on the deposition characteristics of ammonium chloride particles in a hydrogenation air cooler

Experimental study on the deposition characteristics of ammonium chloride particles in a hydrogenation air cooler

Numerical study of underwater oil spill diffusion in complex hydrodynamic environments

Waves and currents are key dynamic factors that influence the diffusion of underwater oil spills. To study the behavior of such spills under complex hydrodynamic conditions, an oil spill diffusion numerical model was established and physically verified by model test data. The drift and diffusion of crude oil from seabed to surface under current, wave, and wave–current coupling conditions were analyzed. The results reveal that under the wave–current coupling condition, the oil spill diffusion exhibits the movement characteristics of oil particles influenced by both currents and waves. The oil particles oscillate with water particles while simultaneously diffusing in the direction of the water flow. The rising speed of oil droplets is fastest in still water but slows significantly under the influence of waves and currents. The shape of the oil slick at the leakage point is related to the hydrodynamic conditions. The oil slick diffuses vertically upwards in still water. While in current and wave conditions, it takes on “C” and “Z” shapes, respectively. Under the influence of the wave–current coupling, the slick spreads in an “S” shape. Moreover, the faster the oil spill, the more significant the entrainment effect, leading to an intensified lateral and vertical diffusion of the oil particles. These research findings offer valuable insights for tracking underwater oil spill trajectories during accidents.

The Combination of X-ray Ct and Multi-particle Finite Element Method for Powder Compaction

Abstract The macroscopic mechanical properties of granular materials are closely related to their microscopic properties, and studying the compression problem of powder is helpful for establishing a constitutive law of powder compaction process. This study utilized X-ray CT technology to investigate the 3D numerical analysis model of loose particle stacking and compaction based on MPFEM, and investigated the mechanical behavior of powder under compression. The results of MPFEM were experimentally verified through powder uniaxial compression experiments, and the results showed that the calculated results of MPFEM were in good agreement with the experimental results. The method of X-ray CT can effectively capture the geometric characteristics of powder particles, and the MPFEM can obtain the true characteristics of plastic deformation of powder bodies, which is an important means of developing powder compaction constitutive models.

Diffusion characteristics of re-suspended PM2.5 within a radiant floor heating room under various ventilation modes

Few studies have revealed the effects of re-suspension of particulate matter deposited by radiant floor heating on indoor environments. The present study utilized Computational Fluid Dynamics (CFD) to investigate the impact of radiant floor heating and ventilation mode on indoor airflow patterns, as well as the dispersion and migration of re-suspended particulate matter, based on a turbulence model validated by an environmental test cabin. The Archimedes number (Ar) was employed to represent the strength of interaction between the thermal buoyancy force generated by floor radiation and the inertial force of the supply airflow. The results indicates that as Ar increases, the supply airflow exhibits a downward deflection, thereby forming a stable vortex below to prevent the diffusion of heat and re-suspended PM2.5 generated from the heated floor. As the Ar increases, the re-suspended PM2.5 deposited on the surrounding walls increased significantly, and the indoor PM2.5 concentration gradually decreased. When the Ar exceeds 6.03, the increase in Ar will no longer affect the indoor re-suspension PM2.5 diffusion, deposition characteristics, and removal efficiency. Therefore, it is recommended the critical Ar (Arcrit) of 6.03 for a radiant floor heating room under various ventilation modes, beyond which the indoor flow structure and distribution characteristics of re-suspended PM2.5 no longer change with increasing Ar. This study is helpful to further understand the diffusion and distribution characteristics of re-suspended particulates in floor heating and ventilation rooms, and provide technical reference for improving indoor air quality.

Fabrication and characterization of potato short amylose, zein, and pectin ternary composite particles stabilized pickering emulsions and their application on nuciferine delivery

Nuciferine exhibits properties such as reducing blood sugar and fat, however, it is hindered by its poor water solubility and low bioavailability. Pickering emulsions can efficiently encapsulate, protect and deliver active ingredients. In recent years, the use of biologically derived natural materials as emulsifiers to construct Pickering emulsions has become a research hotspot. This research utilized an enzymatic hydrolysis technique to produce short amylose. Subsequently, a ternary composite of short amylose (DBS), zein, and pectin (PEC) was formulated to stabilize Pickering emulsion, with the incorporation of nuciferine aiming to enhance the performance of lotus leaves in terms of both stability and bioavailability. The study revealed that varying amounts of DBS addition had a significant impact on the micromorphological structure and functional properties of DBS-Zein-PEC ternary composite particles. Specifically, the addition of 0.4 g of DBS led to a notable reduction in particle size to 735.2 nm and Zeta potential to −29.6 mV, creating a three-dimensional network with a closely packed lamellar structure. Optimal process conditions for preparing Pickering emulsion included a 3-minute homogenization time, rotation speed of 15000 rpm, and 5 % ternary composite particle addition. Under these conditions, O/W Pickering emulsion was successfully prepared, achieving a 90.5 % encapsulation rate for nuciferine. The resulting emulsion exhibited a minimum particle size of 4.09 μm, displayed good storage stability, resistance to salt ions and pH variations, viscous fluid characteristics, tolerance to oral and gastric environments, and slow release of nuciferine in the small intestine, thereby enhancing its bioavailability. These findings offer insights into the loading and delivery of nuciferine and serve as a technical guide for developing highly stable emulsion gel systems.

Using NMR linewidth broadening for magnetic characterization of micrometer-size particles in silicone matrix

Standard magnetization measurements on samples of small magnetic particles may generate conflicting results. We compare the mass magnetization of MgZn ferrite particles in a compressed bulk material and in dry powder and find that at low fields the values can differ by as much as 50%. We show here that embedding the particles in a silicone matrix and measuring the NMR linewidth in combination with simulations establishes a new method to evaluate the magnetization of the particles at different fields and temperatures. The NMR results agree with the direct magnetization measurements of the powder samples and the magnetization measurements of the particles embedded in silicone. This work is motivated, in part, by studies on using small magnetic particles as MRI temperature indicators, and we compare the effectiveness of these particles for low-field and high-field MRI thermometry.

LIBS as a fast and reliable alternative to µXRF and SEM–EDX for quantitative analysis of aluminium alloy particles in technical cleanliness analysis

The characterization of metal alloy (particle) characterization is a vital tool in today’s high–tech applications for quality and process control in industry, especially for applications in technical cleanliness analysis (TCA). Here, metal alloy fragments down to sizes of 200 µm need to be quantitatively characterized as accurate as possible. Laser-induced breakdown spectroscopy (LIBS) offers several advantages due to its easy use, short measurements times, and high sensitivity. To enable the application of LIBS in this context, the method must yield adequately accurate results. Therefore, in this study we assess the performance of LIBS by comparison with well–established methods – scanning electron microscopy coupled with energy-dispersive X‑ray spectroscopy (SEM-EDX) and µ‑X‑ray fluorescence (µXRF). We analyse particulate certified reference materials consecutively with non–destructive and destructive methods on the quantitative composition regarding the key elements necessary for distinguishing aluminium alloys: Si, Zn, Mn, Mg, Cu and Fe. Sample inhomogeneity and the effect of sampling location and area is shown via microstructure analysis and combined with an assessment of the analysis volume for each used method. By evaluating the data statistically and by comparing quantitative results achieved with different methods, we can postulate a high agreement between LIBS and the studied reference methods, providing a basis for the use of LIBS in industrial analysis of metal alloy particles.

Study on the particle dynamic characteristics in a centrifugal pump based on an improved computational fluid dynamics-discrete element model

To accurately investigate the solid–liquid flow mechanisms within the pump, this study employs an improved Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) approach to examine the solid–liquid interactions in a centrifugal pump. First, the improved CFD-DEM is introduced, focusing on turbulence dissipation near the wall and velocity reconstruction. Then, a comparison is made between the CFD-DEM's performance before and after the enhancements. Finally, an analysis is conducted on how the dynamic characteristics of particles within the pump vary under different solid phase concentration conditions. The study revealed that the particle distribution from the corrected CFD-DEM aligns more closely with the experimental results. At a 2% concentration under the design conditions, the head error was reduced by 0.476%, while the efficiency error decreased by 0.076%. Additionally, as the solid phase concentration increased, there was a corresponding rise in the impact power loss of the particles, dissipative power loss, collision frequency, peak values of particle collisions, and the degree of overlap during these collisions. The comparison revealed that the pressure gradient force has the most significant impact on particle motion. As the pressure gradient force increases, the shear power dissipation of the particles also rises. For solid phase concentrations ranging from 1% to 4%, the average shear power variation during the computation period is between 4.28 × 10−6 W and 5.68 × 10−6 W. As the solid phase concentration increases, the volume fraction of the solid phase distribution on the component wall also gradually rises. These findings provide valuable insights for enhancing the accuracy of research on solid–liquid flow in centrifugal pumps.

The deposition characteristics of particles after collision by using the direct simulation Monte Carlo method

The deposition characteristics of particles after collision by using the direct simulation Monte Carlo method

EPR spectroscopic characterization of neutron-irradiated nanocrystalline anatase particles

This study investigates the effects of neutron irradiation on nanocrystalline anatase (TiO₂) using electron paramagnetic resonance (EPR) spectroscopy. Neutron irradiation doses of 1.6 × 101⁵, 8 × 101⁵, 4 × 101⁶, and 2 × 101⁷ n/cm2 were applied to TiO₂ samples, and changes in the EPR spectra were analyzed to explore the transmutation of titanium (Ti) atoms into vanadium (V). The results reveal that the irradiation induces the conversion of 50Ti to 51V via neutron capture, accompanied by the formation of oxygen and titanium vacancies. The intensity of the EPR signal decreases with increasing neutron dose, indicating that the formation of 51V isotopes and other irradiation-induced effects influence the material's paramagnetic behavior. The study provides insights into the transmutation process and highlights the potential of neutron irradiation for modifying the properties of TiO₂, with implications for photocatalytic applications and radiation-resistant materials.

Comparison of two automated urine cytometry systems: Sysmex® UF-1000i and Beckman Coulter® DxU 850 Iris

Background: Urinary tract infection, defined as the presence of bacteria or yeast in the urinary tract, is the most common community-acquired infection after respiratory infections. The cytobacteriological examination of urine (CBEU) remains the primary diagnostic test for urinary tract infections and is the most frequently conducted test in microbiology laboratories. Direct examination is a crucial step of CBEU, enabling the assessment of cytology, including leukocytes and red blood cells, as well as the identification of crystals, epithelial cells, and microorganisms when present in significant quantities. This examination also provides preliminary results that can guide clinical decision-making. While the standard method for urine cytology is a microscopic examination, automation offers several advantages, including standardized results with higher repeatability, improved reproducibility, increased sample throughput, and seamless data transfer to laboratory information systems. Objectives: This study aimed to compare the performance of two automated urine cytology systems: Sysmex UF-1000i and the Beckman Coulter DxU 850 Iris. Methods: We described the methodology and technology underlying each system and assessed their analytical performance. The UF-1000i uses flow cytometry for the objective characterization and identification of particles based on forward scattering, fluorescence, and adaptive typing analysis. In contrast, the DxU-850 Iris, a urine microscopy analyzer, employs proprietary digital flow morphology technology alongside automatic particle recognition software to isolate, identify, and characterize digital images of particles. Conclusion: Our comparison showed that both systems performed exceptionally well, delivering results that are comparable, and, in some cases, superior to, those obtained through the reference method of optical microscopy.

Effect of Process Parameters on Nano-Microparticle Formation During Supercritical Antisolvent Process Using Mixed Solvent: Application for Enhanced Dissolution and Oral Bioavailability of Telmisartan Through Particle-Size Control Based on Experimental Design

Background/Objectives: This study investigates the impact of supercritical antisolvent (SAS) process parameters on the particle formation of telmisartan, a poorly water-soluble drug. Methods: A fractional factorial design was employed to examine the influence of the SAS process parameters, including solvent ratio, drug solution concentration, temperature, pressure, injection rate of drug solution, and CO₂ flow rate, on particle formation. Solid-state characterizations of the SAS process particles using XRD and FT-IR confirmed their amorphous nature. The effect of particle size on the kinetic solubility, dissolution, and oral bioavailability of telmisartan was also assessed. Results: Using a mixture of dichloromethane and methanol, telmisartan amorphous nano-microparticles with sizes between 200 and 2000 nm were produced. The key parameters, particularly drug solution concentration and temperature, significantly affected the particle size. Interestingly, the ratio of the solvent mixture also had a significant effect on the particle morphology. Further experiments were performed to determine the conditions for preparing telmisartan amorphous nano-microparticles with various sizes by controlling the solvent mixture ratio and the concentration of the drug solution. It was revealed that a reduction in the amorphous particle size enhanced both the kinetic solubility and dissolution rates, leading to a significantly increased in vivo oral bioavailability in rats compared to unprocessed telmisartan. Conclusions: These findings suggest that SAS processing, utilizing adjustments of process parameters, offers an effective strategy for enhancing the bioavailability of poorly soluble drugs by generating amorphous spherical nano-microparticles with optimized particle size.

An improved method to process the data of optical Fiber signals for identifying the instantaneous flow structure in a gas-solid fluidized bed

The instantaneous signals recorded with the optical fiber probe (OFP) directly reflect the hydrodynamic behaviors in fluidized beds. A new data-processing method is put forward to calculate the threshold voltage that is used to discern the bubble phase and emulsion phase. It is found that the threshold voltage is not only related to the flow pattern but also to the color of the used particles. Then the data-processing programs including the Fast Fourier filter have been developed for determining the flow characteristics such as the bubble/particle velocity, bubble/agglomerations chord length, etc. By comparing them with other different methods, the suitability of the proposed method for quantifying the hydrodynamic behaviors in bubble/turbulent fluidized beds is verified. Finally, this method is employed to analyze the characteristics of bubbles, agglomerations and particles in a gas-solid fluidized bed. It is found that the hydrodynamic behaviors of bubbling beds and turbulent beds have significant differences.

Experimental study on the motion characteristics of non-spherical biomass particulate systems in a fluidization tube

This study experimentally investigated the transport characteristics of flaky, fibrous and streaky biomass particles in a fluidization tube. The movement and distribution of these non-spherical biomass particles in different sections of the fluidization tube were visualized and analyzed by using a Particle Tracking Velocimetry measuring approach. The method for calculating the solidity rate distribution of particles in the fluidization tube was also developed. Furthermore, the distribution patterns of non-spherical biomass particles with three different morphologies in the near-wall region of the fluidization tube were significantly analyzed. It could be observed that the area of the non-spherical biomass particles in the near-wall region exhibited an ’M’ shape. Three empirical formulas for predicting the maximum area of non-spherical biomass particle clusters in the fluidization tube were firstly proposed. Among the three prediction formulas, the correlation coefficients are 0.7142, 0.8797, and 0.9567, respectively.

Catalytic gasification of a single coal char particle: An experimental and simulation study

The catalytic coal gasification technology has been widely researched and developed under the background of “Carbon peaking and carbon neutrality goals”. Currently, most of catalytic gasification experiments on coal char particles are analyzed by thermogravimetric analyzer (TGA). However, the gasification agent will be subject to diffusion resistance during the reaction because of the sample stacking, making the inherent reaction kinetics unclear. In this study, we investigated the catalytic gasification behavior of single-particle coal char using high temperature stage microscope (HTSM). With the diffusion resistance ruled out, the reaction conditions when using a HTSM are more similar to those inside a real industrial gasifier. Numerical models of the gasification reaction of single-particle coal char were further developed using the kinetic parameters obtained under HTSM. Three models were investigated, including regular spherical structured, irregular spherical structured and porous spherical structured models, representing different morphologies of coal char particles in the gasifier. The gasification characteristics of coal char particles under different K2CO3 catalyst loadings and gasification temperatures were also studied. Compared with the activation energies data of coal char particles without catalyst, the activation energies of coal char particles loaded with 2.2 %, 4.4 %, 6.6 %, and 10.0 % catalysts were reduced by 110 kJ/mol, 116 kJ/mol, 121 kJ/mol, and 126 kJ/mol, respectively. The reaction surface area affects the temperature distribution. The temperature near the irregular spherical particle is about 20 K higher than the temperature near the regular spherical particle.