Characterization Of Particles Research Articles

Collision characteristics of coal particles in arc-shaped plug elbow for pneumatic conveying

Particle collisions are one of the main causes of elbow wear. In this study, an arc-shaped plug elbow was proposed. Combined with the pneumatic conveying experiment of coal particles and the computational fluid dynamics and discrete element method (CFD–DEM) simulation of Euler–Lagrangian bilateral coupling, the variation rules of particle distribution, elbow wear, particle velocity, and collision energy loss were analyzed, the weakening characteristics of the arc-shaped plug on particle collision and elbow wear were revealed, and the criterion of the optimal structure was deduced. The results show that the arc angle is the main factor influencing particle collision and elbow wear in arc-shaped plugs, which determines the reasonable range of the dimensionless height. The average particle velocity of the arc-shaped plug elbow decreased rapidly during the plug-filling stage and was much lower than that of an ordinary elbow during the stable conveying stage. The growth rate of the collision energy loss tends to stabilize after stable particle accumulation. This is an important criterion for the optimal structure, in which the arc angle satisfies the condition that the plug completely contains the radiation area of the wear center, and the dimensionless height satisfies the condition that stable particle accumulation is formed in the plug.

Oxidative potential associated with reactive oxygen species of size-resolved particles: The important role of the specific sources

Oxidative potential (OP) is a predictor of particulate matter (PM) toxicity. Size-resolved PM and its components that influence OP values can be generated from several sources. However, There is little research have attempted to determine the PM toxicity generated from specific sources. This paper studied the OP characterization and reactive oxygen species (ROS) formation of particles from specific sources and their effects on human health. OP associated with ROS of size-resolved particles was analyzed by using dithiothreitol (DTT) method and electron paramagnetic resonance (EPR) spectroscopy technology. And OP and ROS deposition of specific source PM were calculated for health through the Multi-path particle deposition (MPPD) model. The results evidenced that the highest water-soluble OP (OPws) from traffic sources (OPm: 104.50 nmol min−1·ug−1; OPv: 160.15 nmol min−1·m−3) and the lowest from ocean sources (OPm: 22.25 nmol⋅min−1⋅ug−1; OPv: 54.16 nmol min−1·m−3). The OPws allocation in PM from different sources all have a unimodal pattern range from 0.4 to 3.2 μm. ROS (·OH) displayed the uniform trend as PM OPws, indicating that PM< 3.2 is the major contributor to adverse health impacts for size-resolved PM because of its enhanced oxidative activity compared with PM> 3.2. Furthermore, this study predicted the DTT consumption of PM were assigned to different components. Most DTT losses are attributed to the transition metals. For specific sources, transition metals dominates DTT losses, accounting for 38%–80% of DTT losses from different sources, followed by Hulis-C, accounting for 1%–10%. MPPD model calculates that over 66% of pulmonary DTT loss comes by PM< 3.2, and over 71% of pulmonary ROS generation from PM< 3.2. Among these sources of pollution, traffic emissions are the primary contributors to reactive oxygen species (ROS) in environmental particulate matter (PM). Therefore, emphasis should be placed on controlling traffic emissions, especially in coastal areas.

Uncovering the crystallography and formation mechanism of nanoscale clusters in Sb-rich SPPs of a p-type (Bi, Sb)2Te3 alloy.

Considering that the crystallographic characteristics of the Sb-rich secondary phase particles (SPPs) greatly affect the thermoelectric properties of Bi2Te3 based materials, it is of great significance to explore the mechanism behind the Sb-rich SPPs in the p-type (Bi, Sb)2Te3 material. Here a conventional TEM technique was used to characterize the composition, size and distribution of Sb-rich SPPs in a spark plasma sintered p-type (Bi, Sb)2Te3 alloy. The results indicated that two different morphologies of Sb-rich SPPs including elongated and circular Sb-rich SPPs were frequently observed. Combined with high-resolution transmission electron microscopy, this work provides atomic-scale evidence for the formation mechanism behind the Sb-rich SPPs in the (Bi, Sb)2Te3 material.

Extraction and Characterization of Cellulose from Coffee Husk and Brewery’s Spent Grain Fibers Using Alkali-Hydrogen Peroxide Treatment Method

Coffee husk (CH) and brewery spent grain (BSG) fibers are sustainable industrial residues that consist of cellulose. The present study aimed at the extraction of cellulose from CH and BSG fibers and to study the effect of alkali-hydrogen peroxide (5% NaOH–7% H2O2) treatment during the extraction by characterizing the extracted cellulose. Characterization of cellulose particles, such as crystallinity, functional groups, thermal properties, and morphology, was conducted by performing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), and scanning electron microscopy (SEM), respectively. The finding shows that the maximum cellulose yields obtained from CH and BSG fibers are 37.3% and 26.5%, respectively. From the XRD results, the cellulose obtained from CH fiber (C-CH) and from BSG fiber (C-BSG) showed diffractive peaks with the highest intensity of approximately 1,003 and 1,236 counted at 2θ = 22°, respectively. A reduction in the absorption of peaks was observed on the FTIR spectrum for both C-BSG and C-CH samples at different wavelengths. SEM demonstrated that the surface roughness of the celluloses was enhanced. TGA showed that the maximum temperature decomposition observed for both C-CH and C-BSG is 360°C and 380°C, respectively. Generally, in this study, alkali-hydrogen peroxide (5% NaOH–7% H2O2) treatment was effectively used for the treatment of BSG and CH fibers for the extraction and surface modification of cellulose particles. The extracted cellulose in the present study can be used as an alternative to conventional cellulose for the manufacturing of biocomposite materials, preparation of particle boards and furniture, and production of food packaging materials.

Characteristics of Anthropogenic Pollution in the Atmospheric Air of South-Western Svalbard (Hornsund, Spring 2019)

The character of atmospheric pollution and its impact on surface waters may vary substantially in space, and hence, we add a potentially important location for the studies of atmospheric air pollution to the map of the High Arctic. We have investigated the anthropogenic particle characteristics and selected persistent organic pollutant concentrations, in a priorly unmonitored location in the Arctic (Svalbard), exposed to a climatic gradient. Single-particle analysis of PM indicates that besides the prevailing natural aerosol particles, anthropogenic ones were present. The likely anthropogenic origin of some particles was established for spherical Fe-rich or aluminosilicate particles formed in high-temperature processes or metal-rich particles of the chemical composition corresponding to industrial products and atypical for natural minerals; soot, tar balls, and secondary sulfate were also likely of anthropogenic origin. Some of the observed anthropogenic particles could only come from remote industrial sources. POP concentrations indicated a background of LRAT, consistent with the ΣPCB concentrations and volatility profile. However, the ΣDDX composition indicating aged sources and an order of magnitude higher concentrations of both ΣDDXs and ΣHCHs than at other High Arctic monitoring stations indicate their potential source in two types of re-emission from secondary sources, i.e., from seawater and snowpack, respectively.

Integrating optical and electrical sensing with machine learning for advanced particle characterization

Particle classification plays a crucial role in various scientific and technological applications, such as differentiating between bacteria and viruses in healthcare applications or identifying and classifying cancer cells. This technique requires accurate and efficient analysis of particle properties. In this study, we investigated the integration of electrical and optical features through a multimodal approach for particle classification. Machine learning classifier algorithms were applied to evaluate the impact of combining these measurements. Our results demonstrate the superiority of the multimodal approach over analyzing electrical or optical features independently. We achieved an average test accuracy of 94.9% by integrating both modalities, compared to 66.4% for electrical features alone and 90.7% for optical features alone. This highlights the complementary nature of electrical and optical information and its potential for enhancing classification performance. By leveraging electrical sensing and optical imaging techniques, our multimodal approach provides deeper insights into particle properties and offers a more comprehensive understanding of complex biological systems.Graphical abstract

Analysis of Individual Viral Particles by Flow Virometry

This review focuses on the emerging field of flow virometry, the study and characterization of individual viral particles using flow cytometry instruments and protocols optimized for the detection of nanoscale events. Flow virometry faces considerable technical challenges including minimal light scattering by small viruses that complicates detection, coincidental detection of multiple small particles due to their high concentrations, and challenges with sample preparation including the inability to easily “wash” samples to remove unbound fluorescent antibodies. We will discuss how the field has overcome these challenges to reveal novel insights into viral biology.

Fabrication and Characterization of Pectin Films Containing Solid Lipid Nanoparticles for Buccal Delivery of Fluconazole.

Fluconazole (FZ) is a potential antifungal compound for treating superficial and systemic candidiasis. However, the use of conventional oral drug products has some limitations. The development of buccal film may be a potential alternative to oral formulations for FZ delivery. The present study involved the development of novel FZ-loaded solid lipid nanoparticles (FZ-SLNs) in pectin solutions and the investigation of their particle characteristics. The particle sizes of the obtained FZ-SLNs were in the nanoscale range. To produce pectin films with FZ-SLNs, four formulations were selected based on the small particle size of FZ-SLNs and their suitable polydispersity index. The mean particle sizes of all chosen FZ-SLNs formulations did not exceed 131.7 nm, and the mean polydispersity index of each formulation was less than 0.5. The properties of films containing FZ-SLNs were then assessed. The preparation of all FZ-SLN-loaded pectin films provided the mucoadhesive matrices. The evaluation of mechanical properties unveiled the influence of particle size variation in FZ-SLNs on the integrity of the film. The Fourier-transform infrared spectra indicated that hydrogen bonds could potentially form between the pectin-based matrix and the constituents of FZ-SLNs. The differential scanning calorimetry thermogram of each pectin film with FZ-SLNs revealed that the formulation was thermally stable and behaved in a solid state at 37 °C. According to a drug release study, a sustained drug release pattern with a burst in the initial stage for all films may be advantageous for reducing the lag period of drug release. All prepared films with FZ-SLNs provided a sustained release of FZ over 6 h. The films containing FZ-SLNs with a small particle size provided good permeability across the porcine mucosa. All film samples demonstrated antifungal properties. These results suggest the potential utility of pectin films incorporating FZ-SLNs for buccal administration.

Preparation and In Vitro Characterization of Lactococcus lactis-Loaded Alginate Particles as a Promising Delivery Tool for Periodontal Probiotic Therapy.

Probiotic microorganisms are used in a variety of food supplements and medical formulations to promote human health. In periodontal therapy, probiotics are mainly used in the form of gels, tablets or rinses that often tend to leak from the periodontal pocket, resulting in a strongly reduced therapeutic effect. In this pilot in vitro study, we present biodegradable alginate-based particles as an alternative, highly efficient system for a periodontal delivery of probiotic bacteria to the inflammation site. For this purpose, Lactococcus (L.) lactis was encapsulated using a standardized pump-controlled extrusion-dripping method. Time-dependent bacterial release in artificial saliva was investigated over 9 days. The effect of freeze drying was explored to ensure long-term storage of L. lactis-loaded particles. Additionally, the particles were bound to dentin surface using approved bioadhesives and subjected to shear stress in a hydrodynamic flow chamber that mimics the oral cavity in vitro. Thus, round particles within the range of 0.80-1.75 mm in radius could be produced, whereby the diameter of the dripping tip had the most significant impact on the size. Although both small and large particles demonstrated a similar release trend of L. lactis, the release rate was significantly higher in the former. Following lyophilization, particles could restore their original shape within 4 h in artificial saliva; thereby, the bacterial viability was not affected. The attachment strength to dentin intensified by an adhesive could resist forces between 10 and 25 N/m2. Full degradation of the particles was observed after 20 days in artificial saliva. Therefore, alginate particles display a valuable probiotic carrier for periodontal applications that have several crucial advantages over existing preparations: a highly stable form, prolonged continuous release of therapeutic bacteria, precise manufacturing according to required dimensions at the application site, strong attachment to the tooth with low risk of dislocation, high biocompatibility and biodegradability.

Optofluidic Force Induction Meets Raman Spectroscopy and Inductively Coupled Plasma-Mass Spectrometry: A New Hyphenated Technique for Comprehensive and Complementary Characterizations of Single Particles.

Nanoparticles are produced at accelerating rates, are increasingly integrated into scientific and industrial applications, and are widely discharged into the environment. Analytical techniques are required to characterize parameters such as particle number concentrations, mass and size distributions, molecular and elemental compositions, and particle stability. This is not only relevant to investigate their utility for various industrial or medical applications and for controlling the manufacturing processes but also to assess toxicity and environmental fate. Different analytical strategies aim to characterize certain facets of particles but are difficult to combine to retrieve relevant parameters coherently and to provide a more comprehensive picture. In this work, we demonstrate the first online hyphenation of optofluidic force induction (OF2i) with Raman spectroscopy and inductively coupled plasma-time-of-flight-mass spectrometry (ICP-TOFMS) to harness their complementary technology-specific advantages and to promote comprehensive particle characterizations. We optically trapped individual particles on a weakly focused vortex laser beam by aligning a microfluidic flow antiparallelly to the laser propagation direction. The position of particles in this optical trap depended on the hydrodynamic diameter and therefore enabled size calibration as well as matrix elimination. Additionally, laser light scattered on particles was analyzed in a single particle (SP) Raman spectroscopy setup for the identification of particulate species and phases. Finally, particles were characterized regarding elemental composition and their distributions in mass and size using SP ICP-TOFMS. In a proof of concept, we analyzed polystyrene-based microplastic and TiO2 nanoparticles and demonstrated the opportunities provided through the coupling of OF2i with SP Raman and SP ICP-TOFMS.

One-Pot Preparation of Mixed-Mode Reversed-Phase Anion-Exchange Silica Sorbent and its Application in the Detection of Cyclopiazonic Acid in Feeds and Agricultural Products.

A novel co-bonded octyl and pyridine silica (OPS) sorbent was prepared and applied for the solid phase extraction (SPE) of cyclopiazonic acid (CPA, a type of mycotoxin) in feed and agricultural products for the first time. A simple mixed-ligand one-pot reaction strategy was employed for OPS sorbent preparation. Nitrogen adsorption-desorption measurements, elemental analysis (EI), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) analysis demonstrated the successful immobilization of octyl and quaternary ammonium groups onto the surface of silica gel. The large specific surface area, high-density functional groups, and mixed-mode anion-exchange characteristics of these silica particles made them the ideal material for the efficient extraction of CPA. Additionally, the OPS sorbents displayed excellent batch-to-batch reproducibility, satisfactory reusability, and low cost. The SPE parameters were optimized to explore the ionic and hydrophobic interactions between CPA and the functional groups, and the ultra-high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-MS/MS) parameters were optimized to obtain a desirable extraction efficiency and high sensitivity to CPA. Meanwhile, the OPS sorbent presented a satisfactory extraction selectivity and low matrix effect. Under the optimized conditions, our developed CPA detection method was used to determine CPA level in rice, wheat flour, corn flour, peanut, and feed samples, exhibiting a lower detection limit, better linearity, higher sensitivity, and satisfactory extraction recovery rate than previously reported methods. Therefore, our method can be preferentially used as a method for the detection of CPA in agricultural products and feeds.

In vivo assessment of TiO2based wear nanoparticles in periprosthetic tissues.

A multimodal approach combining inductively coupled plasma mass spectrometry (ICP-MS), single-particle ICP-MS (spICP-MS), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) and Raman spectroscopy enabled a deeper insight into the balance between total titanium (Ti), the soluble titanium fraction and titanium dioxidebased particle fraction levels in periprosthetic tissues collected from patients undergoing revision surgery. Hydrofluoric acid usage in the sample digestion allowed for complete digestion of TiO2 particles, thus enabling accurate estimation of total Ti levels. The TiO2 fraction represents 38-94% of the titanium load in the six samples where particles were detected, and the fraction is present mainly in samples from patients with aseptically loosened total hip arthroplasty. Further attention was given to this fraction determining the elemental composition, particle count, particle size and modification of TiO2. The spICP-MS analysis confirmed the presence of the TiO2-derived (nano)particles (NPs) with a 39- to 187-nm median size and particle count up to 2.3 × 1011 particles per gram of tissue. On top of that, the SEM-EDS confirmed the presence of the TiO2 nanoparticles with 230-nm median size and an anatase crystal phasewas determined by Raman spectroscopy. This study presents a novel multimodal approach for TiO2 particle determination and characterization in tissue samples and is the first in vivo study of this character.

RotoBOD─Quantifying Oxygen Consumption by Suspended Particles and Organisms.

Sinking or floating is the natural state of planktonic organisms and particles in the ocean. Simulating these conditions is critical when making measurements, such as respirometry, because they allow the natural exchange of substrates and products between sinking particles and water flowing around them and prevent organisms that are accustomed to motion from changing their metabolism. We developed a rotating incubator, the RotoBOD (named after its capability to rotate and determine biological oxygen demand, BOD), that uniquely enables automated oxygen measurements in small volumes while keeping the samples in their natural state of suspension. This allows highly sensitive rate measurements of oxygen utilization and subsequent characterization of single particles or small planktonic organisms, such as copepods, jellyfish, or protists. As this approach is nondestructive, it can be combined with several further measurements during and after the incubation, such as stable isotope additions and molecular analyses. This makes the instrument useful for ecologists, biogeochemists, and potentially other user groups such as aquaculture facilities. Here, we present the technical background of our newly developed apparatus and provide examples of how it can be utilized to determine oxygen production and consumption in small organisms and particles.

Experimental Study on Strength Enhancement and Porosity Variation of 3D-Printed Gypsum Rocks: Insights on Vacuum Infiltration Post-Processing

AbstractThree-dimensional printing (3DP) technology has shown great potential in rock mechanics and mining engineering due to its ability to create complex and customized objects with high precision and accuracy. At present, an emerging research focus is improving the mechanical properties of 3D-printed samples, which originally has low strength and stiffness, to match those of natural rocks. The objective of this study was to investigate the effectiveness of different post-treatments on the strength enhancement of 3D-printed gypsum samples. To achieve this goal, 3D-printed gypsum samples were subjected to different post-treatments including dipped infiltration treatment and vacuum infiltration treatment using different infiltrants: water, saltwater, ColorBond, and StrengthMax. Subsequently, each sample was subjected to ultrasonic wave velocity testing and uniaxial compression experiments to characterize their mechanical properties, CT scans to investigate their microstructural characteristics. Additionally, X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) tests were conducted to explore the underlying reasons for changes in macroscopic strength. Finally, the physical characteristics and mechanical properties of untreated and post-processed 3D-printed gypsum samples were compared with natural rocks. The results showed that the strength of samples treated with water and saltwater was much lower than that of those treated with ColorBond and StrengthMax, while the porosity was the opposite. In water-treated and saltwater-treated samples, water or saltwater treatment can alter particle characteristics, but weak adhesive bonding and numerous pores result in low mechanical strength. Samples treated with Colorbond or StrengthMax exhibit improved strength due to effective gap filling and cohesive structure formation, with StrengthMax-treated samples showing higher strength despite having more pores than Colorbond-treated ones. Moreover, the physical and mechanical properties of these treated samples matched a wider range of natural rock types compared to the untreated samples.

Anthropogenic particle abundance and characteristics in seawater and intertidal sediments of the Tonkin Bay Coast (North Vietnam).

Microplastics (MPs, plastic items from 1µm to 5mm in size) are present in all environmental compartments. The evaluation of their concentration, fate, and spatial distribution is still a challenge for the scientific community. This concern is just debuting in developing countries, (i.e., Asia, South America, and Africa). This study deals with the MP contamination in the abiotic marine compartments of Northern Vietnam: seawater and intertidal sediments. Four sites located in the intertidal zone or near the coastline in Tonkin Bay, Vietnam were studied. A total of 16 samples (eight for each compartment) were collected in July 2020 (rainy season) and January 2021 (dry season). Anthropogenic particles (total observed fibers and fragments) were found at levels ranging from 3 to 303 particles/m3 in seawater and from 63 to 955 particles/kg dry weight in sediments. Most of these were fibers less than 300-µm long. Higher levels of seawater at the Nam Dinh site were found in the rainy season compared to the dry one. As the river flow was estimated six times higher during the rainy season than during the dry season, these results suggest the river discharge is a potential source of contamination for the coastal zone. The temporal variability was lower for the sediments than for the seawater, suggesting the long-term integration of the anthropogenic particles in this compartment. A small portion of sorted particles were analyzed by µFTIR (8.35%), and this sub-sample was only composed of fragments. Still, fragments were mostly composed of polypropylene (PP, 82%), polyethylene (PE, 9%), and polystyrene (PS, 9%). The fragment size was similar in the two studied compartments, but it was dependent on polymer types since PS fragments (140 ± 17µm) were smaller than those made of PE (622 ± 123µm) and PP (869 ± 905µm). Future works should investigate the smallest fraction of MP (even nanoplastics) as well as find solutions in order to mitigate MP contamination in the marine environment.

Microphysical characterization of boundary layer ice particles: results from a 3-year measurement campaign in interior Alaska

Abstract A three-winter study has been conducted to better understand the relationship between atmospheric conditions and ice fog or diamond dust microphysics. Measurements were conducted east of downtown Fairbanks in the Interior Alaska during non-precipitating conditions. Atmospheric conditions were measured with several weather stations around the Fairbanks region and two Meteorological Temperature Profiler instruments (ATTEX MTP-5HE and MTP-5PE). Near surface ice particle microphysical observations were conducted with the Particle Phase Discriminator (PPD-2K) instrument which measures particles from 8 to 112 μm (sphere-equivalent). Panoramic camera images were captured and saved every ten minutes throughout the campaign for visual assessment of atmospheric conditions. Machine Learning was used to classify both cloud particle microphysical characteristics from the PPD-2K data as well as to categorize boundary layer conditions using the panoramic camera images. For panoramic camera images, data were categorized as: cloudy, clear, fog, snowing, and a nearby powerplant plume was characterized. For the PPD-2K Machine Learning study the scattering pattern images were used to identify: rough surface, pristine, sublimating, and spherical particles. Three additional categories were used to identify indeterminant or saturated images. These categories as well as categories derived from weather station data (e.g., temperature ranges) are used to quantify ice microphysical properties under different conditions. For the complete microphysical dataset, pristine plates or columns accounted for 15.5%, 16.3% appeared to be sublimating particles and 43.4% were complex particles with either rough surfaces or multiple branches. Although the temperature was as warm as −20°C during measurements, only 1.3% of particles were classified as liquid.

Concentration, composition and exposure risk assessment of particulate matter with different particle sizes in subway stations

Particle composition and risk assessment of their exposure in a subway station are very important for a station's environment and the health of people. However, only a handful of papers have compared and analyzed the composition of particulate matter and the risk of their exposure to people. To address these issues, environmental parameters and particulate matter were measured for one month at six different locations in twelve subway stations in a capital city located on the central coast of China. The particulate matter (PM), its composition and characteristics were analyzed and compared. The daily average exposure risk assessment model for the studied city was proposed to analyze the exposure risks associated with various particulate matters and metals for both commuters and workers. The results showed that, in all public areas (station hall, platform and carriage), the concentrations of PM were higher than those outside the subway station. The highest values of PM2.5, PM10, and TSP (total suspended particulates) were determined to be 158.3 μg/m3, 168.0 μg/m3, and 170.7 μg/m3, respectively. The physical characteristics showed that the surface of particles inside the station was rougher, larger and darker in color. Compared to outdoors, the particles within the subway stations contained much more metals, particularly Fe that had the mass fraction of 9.59 %. On the other hand, the outdoor environment did not contain any Fe. These findings indicated that there were original sources of contamination at subway stations, and the hazardous nature of the particles was particularly pronounced within subway stations. The exposure risk of TSP and metals for workers was nearly twice that of passengers. This study aims to provide data that could help in controlling the environment at subway stations.

Turbulence-assisted shear controllable synthesis of silicon oxide micro/nano particles using a counter axial-swirling impinging jet flow reactor

It has been recognised that turbulence shear can be used to effectively control and affect the synthesis of micro/nano particles. The present study focuses on turbulence-assisted shear controllable synthesis of silica (SiO2) micro/nano particles and investigates such shear controllable synthesis process using a counter axial-swirling impinging jet flow vortex flow reactor. Two counter swirling flow streams impinge in the reaction chamber to significantly intensify the local turbulence shear with the aid of ultrasound irradiation. The consequence of the turbulent shear leads to either the trapping of nano-particle nucleus into the turbulent eddies to form the aggregated micro/nana particles or the confinement of the growth of agglomerated micro/nano particles so as to form highly uniform and better morphological micro/nano particles. The experimental results have affirmed the postulation that the local turbulent shear generated by the turbulent eddies with the length scales down to the Kolmogorov length scale may directly interact with the aggregated SiO2 micro/nano particles, influencing the particle spherical morphology and size distribution. In addition, it has been found that synthesis performance can be further improved by intensifying the local turbulent shear through the ultrasound irradiation in the synthesis process. Both CFD simulation and experimental results clearly indicate the existence of the correlation in the synthesized SiO2 micro/nano particle characteristics with the local turbulence shear and mass transfer occurring in counter swirl impinge jet flow.

Preparation, structural characterization, and functional attributes of zein-lysozyme-κ-carrageenan ternary nanocomposites for curcumin encapsulation

The low water solubility and inadequate bioavailability of curcumin significantly hinder its broad biological applications in the realms of food and medicine. There is limited information currently available regarding the particle characteristics and functional capabilities of zein-lysozyme-based nanomaterials. Thereby, the primary goal of the current work is to effectively develop innovative zein-lysozyme-κ-carrageenan complex nanocomposites (ZLKC) as a reliable carrier for curcumin encapsulation. As a result, ZLKC nanoparticles showed a smooth spherical nanostructure with improved encapsulation efficiency. Fourier-transform infrared, fluorescence spectroscopy, dissociation assay, and circular dichroism analysis revealed that hydrophobic and electrostatic interactions and hydrogen bonding were pivotal in the construction and durability of these composites. X-ray diffraction examination affirmed the lack of crystallinity in curcumin encapsulated within nanoparticles. The incorporation of κ-carrageenan significantly improved the physicochemical stability of ZLKC nanoparticles in diverse environmental settings. Additionally, ZLKC nanocomposites demonstrated enhanced antioxidant and antimicrobial properties, as well as sustained release characteristics. Therefore, these findings demonstrate the potential application of ZLKC nanocomposites as delivery materials for encapsulating bioactive substances.

Study on laser ignition and combustion characteristics of micron-sized aluminum and Al-Mg alloys particles

In response to the problems of easy sintering and long ignition delay time of micron aluminum in the combustion of aluminum-containing propellants, choose the way to add magnesium to metal aluminum to construct an alloy system, through boiling, micro-explosions are generated during the ignition and combustion process to weaken the sintering behavior and shorten the ignition delay time of aluminum. Selecting aluminum and Al-Mg alloy powder fuel with a particle diameter of about 10 μm as the research object, a set of individual-particle fuel laser ignition and microscopic high-speed imaging experimental devices was built that can observe the whole process of ignition and combustion of micron-sized fuel. Thermal analysis was used to detect and characterize the thermal decomposition process of micron-sized aluminum and Al-Mg alloy powders; combined with the results of scanning electron microscopy, the difference in ignition performance of micron-sized individual particle aluminum and Al-Mg alloys was studied. Experiments have found that, compared with aluminum, the initial oxidation temperature of Al-Mg alloys is lower and the combustion is more complete. However, the effect of adding magnesium to aluminum is only reflected before 900 °C. The ignition and combustion images and flame propagation laws of micron-sized single-particle aluminum and Al-Mg alloys were obtained. It was found that adding magnesium shortened the ignition delay time, and the combustion produced less residual.