Different Types Of Particles Research Articles

Structure and interactions in reline (1:2 Choline chloride – Urea mixture) according to quantum chemical calculations and molecular dynamics simulation

Quantum chemical calculations using the B3LYP + GD3/6–311++g(2d,2p) method were carried out to study the structure and interactions in a number of complexes containing a choline cation, a chloride anion and urea molecules. The contributions from Coulomb and van der Waals interactions were calculated. The QTAIM method was used to evaluate the strength of various bonds in these complexes. A molecular dynamics simulation of reline was also carried out in the NPT ensemble at a pressure of 1 atm and at temperatures of 298 and 323 K, with the GAFF force field and charges taken from our quantum chemical calculations. The particle radial distribution functions of centers of mass, local mole fraction functions, atom–atom radial distribution functions, and spatial distribution functions were calculated. Particles of different types were shown to form bonds of different types competing with each other.

Spin exchange between paramagnetic probes inside graphite oxide

Heisenberg spin exchange among paramagnetic species in acetonitrile intercalated into graphite oxide was studied. It was found that spin exchange in between the oxidized graphene planes is strongly hindered, and spin-exchange broadening of EPR spectra has not been observed both for particles of the same nature (TEMPO-TEMPO) and for particles of different types (TEMPO-Ni2+). The addition of nickel ions into the “graphite oxide – CH3CN” system led to the absence of the characteristic phase transformation of the high-temperature swelled graphite oxide to the low-temperature one.

Mixing state and effective density of aerosol particles during the Beijing 2022 Olympic Winter Games

Abstract. Mixing state and density are two key parameters of aerosol particles affecting their impacts on radiative forcing and human health. Here a single-particle aerosol mass spectrometer in tandem with a differential mobility analyzer and an aerodynamic aerosol classifier was deployed during the Beijing 2022 Olympic Winter Games (OWG) to investigate the impacts of emission controls on particle mixing state and density. Our results show the dominance of carbonaceous particles comprising mainly total elemental carbon (Total-EC, 13.4 %), total organic carbon (Total-OC, 10.5 %) and Total-ECOC (47.1 %). Particularly, the particles containing organic carbon and sulfate were enhanced significantly during OWG, although those from primary emissions decreased. The composition of carbonaceous particles also changed significantly which was characterized by the decreases in EC mixed with nitrate and sulfate (EC-NS), EC mixed with potassium nitrate (KEC-N), and amine-containing particles and increase in ECOC mixed with nitrate and sulfate (ECOC-NS). This result indicates that emission controls during OWG reduced the mixing of EC with inorganic aerosol species and amines yet increased the mixing of EC with organic aerosol. The average effective density (ρeff) of aerosol particles (150–300 nm) was 1.15 g cm−3 during the non-Olympic Winter Games (nOWG), with higher values during OWG (1.26 g cm−3) due to the increase in secondary particle contribution. In addition, the ρeff of most particles increased with the increases in pollution levels and relative humidity, yet they varied differently for different types of particles, highlighting the impacts of aging and formation processes on the changes of particle density and mixing state.

Calibration of the NEVOD-EAS array for detection of extensive air showers

In this paper we discuss the calibration of the NEVOD-EAS array which is a part of the Experimental Complex NEVOD, as well as the results of studying the response features of its scintillation detectors. We present the results of the detectors energy calibration, performed by comparing their response to different types of particles obtained experimentally and simulated with the Geant4 software package, as well as of the measurements of their timing resolution. We also discuss the results of studies of the light collection non-uniformity of the NEVOD-EAS detectors and of the accuracy of air-shower arrival direction reconstruction, which have been performed using other facilities of the Experimental Complex NEVOD: the muon hodoscope URAGAN and the muon tracking detector DECOR.

Axial gas mixing in conical spouted beds with high density particles

Conical spouted beds operating with high-density particles (ρp > 2500 kg/m3) have recently gained attention because of their potential use as nuclear fuel coaters for next-generation nuclear reactors. In the literature, the number of axial gas mixing studies in conical and conical-cylindrical spouted beds is very limited and all axial mixing studies were carried out with relatively light particles (ρp ≤ 2500 kg/m3). Therefore, the objective of this study was to generate experimental data that can be used to explain the gas axial mixing behavior in conical spouted beds operating with both low- and high-density particles. Experiments were conducted in two (γ = 30°, 60°) conical spouted beds with three different types of particles: zirconia (ρp = 6050 kg/m3), zirconia toughened alumina (ρp = 3700 kg/m3) and glass beads (ρp = 2460 kg/m3). In order to be able to compare experimental data obtained at different conditions, a 1-D convection-diffusion gas mixing model originally developed by San José et al. (1995) was implemented to determine the axial dispersion coefficients. The results show that the axial dispersion coefficients range between 1.75×10−2 m2/s and 9.35×10−2 m2/s, increase with superficial gas velocity and are higher than the corresponding dispersion coefficients of fixed beds, lower than the dispersion coefficients of fluidized beds and in the same range with the cylindrical spouted beds reported in the literature. The corresponding Peclet numbers were in the range of 0.6–7.8 for all operating conditions and slightly higher Peclet numbers were obtained with glass beads indicating the relative importance gas convective transport over gas dispersion for light particles compared to heavy particles.

Investigation of the fractional coupled-Burgers model with the exponential kernel

The present study seeks to develop a collocation method focused on an extended cubic B-spline (ECBS) to approximate the time fractional coupled-burgers (TFCB) equation. Numerous branches of engineering and physical sciences are used to model the TFCB equation. They have been utilized to simulate the sedimentation of scale volume concentrations of two different types of particles in fluid mixtures under the influence of gravity with the non-local time. The non-local time is considered in the form of the Caputo-Fabrizio operator (CFO). The space-direction is discretized via the ECBS functions. In addition, the new theoretical study of the stability and the convergence are also provided and compared with the computational values. Three examples are tested numerically in order to check the feasibility and applicability of the methodology. The graphics are also provided to examine the order of convergence numerically.

Development of Simvastatin-Loaded Particles Using Spray Drying Method for Ex Tempore Preparation of Cartridges for 2D Printing Technology.

In this work, a spray drying method was developed to produce drug/polymer (simvastatin/polycaprolactone) microparticles that have the potential to be used as a pre-formulation for ex tempore preparation of 2D printing cartridges. An experimental model was designed with the process parameters set to predict the smallest particle size required for successful 2D printing. Three different types of particles (lactose, nanocellulose/lactose, calcium silicate) were produced, and the average size of the dry particles varied depending on the sampling location (cyclone, collection vessel). The encapsulation efficiency of simvastatin was highest with nanocellulose/lactose from the collection vessel. The one-month stability of simvastatin in the particles showed low content, but the addition of ascorbic acid as an antioxidant increased the chemical stability of the drug. Interestingly, the addition of antioxidants decreased the stability of simvastatin in the calcium silicate particles from the collection vessel. Dispersion of the particles in three different propylene glycol and water mixtures (10/90, 50/50, and 90/10% (v/v)), representing a printable ink medium with three different viscosity and surface tension properties, showed that nanocellulose/lactose was the most suitable antiadhesive in terms of dispersed particle size (˂1 µm). After one month of storage, the dispersed particles remained in the same size range without undesirable particle agglomeration.

An OpenFOAM solver for computing suspended particles in water currents

Abstract A new OpenFOAM solver has been developed for computing the spatial variation of particle concentrations in flowing water. The new solver was programmed in C ++ using OpenFOAM libraries, and the source code has been made openly available. The current article describes the coding of how the water flow and particle movements are computed. The solver is based on a Eulearian approach, where the particles are computed as concentrations in cells of a grid that resolves the computational domain. The Reynolds-averaged Navier–Stokes equations are solved by simpleFoam, using the k-ε turbulence model. The new solver uses a drift-flux approach to take the fall or rise velocity of the particles into account in a convection-diffusion equation. The model is therefore called sediDriftFoam. The results from the solver were tested on two cases with different types of particles. The first case was a sand trap with sand particles. The geometry was three-dimensional with a recirculation zone. The computed sediment concentrations in three vertical profiles compared well with earlier numerical studies and laboratory measurements. The second case was a straight channel flume with plastic particles that had a positive rise velocity. In this case, the results also compared well with the laboratory measurements.

Features of using Cs2LiYCl6:Ce based scintillation detector for time-of-flight application

A detailed study was made of the systematic uncertainties that arise when a constant fraction method is used for the timing analysis of the signals from a Cs2LiYCl 6:Ce-based detector. It is shown that there is a systematic difference in the rise time of the signals corresponding to the different types of particles. This difference leads to a systematic shift of the timestamp when the constant fraction algorithm is used for timing analysis. The value of the shift of the timestamps between signals corresponding to γ-rays and 6Li(n,t)4He reaction products reaches ∼3.6 ns at neutron energy of 0.6 MeV and ∼2.2 ns for neutron energy of 7.0 MeV. This shift can lead to a significant distortion of the measured results when the position of the prompt γ-rays peak is used to calibrate the time scale of the spectrometer. On the example of some previously obtained results it is shown that the data distortions can be explained by an uncompensated shift in the timestamp.

Poiseuille–Couette flow of a hybrid nanofluid in a vertical channel: Mixed magneto-convection

The study of mutual interaction between flow and external magnetic field, as well as the influence of temperature on the motion, is crucial for new classes of materials involved in nanotechnologies. This paper considers a very common situation where a hybrid nanofluid fills a vertical plane channel with a moving wall. Since the nanofluid is Boussinesquian the flow is induced by the buoyancy and Lorentz forces together with a constant pressure gradient. This problem has many industrial applications so that it is of relevant interest. Using a steady and laminar flow, an exact solution for the ODEs which govern the motion has been found. This is the first time an analytical solution is developed for the problem here considered. Analytical expressions for velocity profile and magnetic field are exhibited graphically. Effect of parameters on the flow characteristics has been discussed also in the case of some real hybrid nanofluids (H2O with Al2O3 and Cu, H2O with Ag and MgO, C2H6O2 with TiO2 and Fe3O4). We also find that the presence of two different types of particles determines an increase in the velocity of the nanofluid in accordance with experimental studies. As usual the presence of the external magnetic field causes a decrease in the velocity. Finally, the reverse flow phenomenon is discussed.

Pulse Shaping for MC via Particle Size

In molecular communication (MC), combining different types of particles at the transmitter is a degree of freedom which can be utilized to improve performance. In this paper, we address the problem of pulse shaping to simplify time synchronization requirements by exploiting and combining the received signal characteristics of particles of different sizes. In particular, we optimize the mixture of particles of different sizes used for transmission in order to support a prescribed detection time period for on-off keying, guaranteeing on average 1) a sufficiently large received signal if a binary one is transmitted, and 2) a low enough received signal if a binary zero is transmitted even in the presence of inter-symbol interference. For illustration, we consider an optimization problem based on a free space diffusion channel model. It is shown that there is a tradeoff between the maximum feasible detection duration and the peak detection value for different particle sizes from the smallest particle size enabling the largest detection duration to the largest particle size minimizing the peak detection value at the expense of a limited detection duration.

Spontaneous demixing of chiral active mixtures in motility-induced phase separation

The demixing and sorting strategies for chiral active mixtures are crucial to the biochemical and pharmaceutical industries. However, it remains uncertain whether chiral mixed particles can spontaneously demix without the aid of specific strategies. In this paper, we investigate the demixing behaviors of binary mixtures in a model of chiral active particles to understand the demixing mechanism of chiral active mixtures. We demonstrate that chiral mixed particles can spontaneously demix in motility-induced phase separation (MIPS). The hidden velocity alignment in MIPS allows particles of different types to accumulate in different clusters, thereby facilitating separation. There exists an optimal angular velocity or packing fraction at which this separation is optimal. Noise (translational or rotational diffusion) can promote mixture separation in certain cases, rather than always being detrimental to the process. Since the order caused by the hidden velocity alignment in this process is not global, the separation behavior is strongly dependent on the system size. Furthermore, we also discovered that the mixture separation caused by MIPS is different from that resulting from explicit velocity alignment. Our findings are crucial for understanding the demixing mechanism of chiral active mixtures and can be applied to experiments attempting to separate various active mixtures in the future.

High levels of microparticles release from biodegradable polylactic acid paper cups compared with polyethylene-lined cups

Polylactic acid (PLA) is a popular replacement for conventional fossil-fuel based plastics products such as polyethylene (PE) due to its high biodegradability and recyclability. Previous studies confirmed that PLA microplastics (MPs) and PE MPs pose similar toxicity risks due to that MPs’ risk is primarily attributed to physical and indirect nutritional effects. Surprisingly, despite the widespread use, there have been very few studies of microparticles released from daily products made of biodegradable materials. We investigated release levels from eight single-use paper cups (SUPCs) lined with PLA and PE film. Under typical hot-beverage preparation conditions, the total number of particles released from PLA SUPCs was 4.2 times higher than that from PE SUPCs, with total numbers of 180,000 ± 31,000 and 43,000 ± 10,000 particles per litre, respectively. 22,000 ± 6,000 MPs were released per litre from PLA, which was 3.6 times the level of MPs released from PE SUPCs. In addition, significant levels of cellulose microfibres were released from PLA SUPCs, with quantities of 38,000 ± 31,000 microfibres per litre, while no such fibres were released from PE SUPCs. It should be noted that the levels of these particles may be underestimated due to the exclusion of nanoparticles (less than 0.8 μm, filter’s pore size), unidentified microparticles with high fluorescence backgrounds and attachments between different types of particles. In summary, a proportionately higher level of release of additive microparticles together with the release of cellulose microparticles are the key difference between biodegradable plastics like PLA and conventional plastic such as PE. Cellulose blending in manufacturing is likely related to higher MPs release from PLA cups than PE cups. Therefore, it is highly recommended to re-assess the manufacturing process, potential health and environmental risks of biodegradable plastic products as well as the formulation of related policies.

76 Combined Exposure to road wear Particles and Diesel Exhaust Particles Induces Enhanced pro-Inflammatory Responses in Cells of the Human Airways

Abstract Ambient particulate matter (PM) is one of the leading environmental mortality risk factors worldwide. PM is not a single entity but consists of a complex and variable mixture of particles from multiple sources. Nevertheless, there is a paucity of experimental studies assessing the potential combinatory effects of different types of particles, and most focus on the effects of individual PM components or mixed PM samples. In the present study, the pro-inflammatory effects of combined exposure to road wear particles and diesel exhaust particles (DEP), two important constituents of traffic-derived PM, were assessed in vitro. Human bronchial epithelial cells (HBEC3-KT) and differentiated THP-1 macrophage-like cells were exposed to road wear particles and two different samples of DEP under submerged conditions, both alone and in combination. Particle-induced release of pro-inflammatory cytokines (CXCL8 and IL-1β) was measured by enzyme-linked immunosorbent assay. The results show that combined exposure to road wear particles and DEP induced enhanced release of pro-inflammatory cytokines compared with the effects of the individual particle samples. The combinatory effects appeared to depend on properties of the DEP samples and also differed between the HBEC3-KT cells and THP-1 macrophage-like cells. This study shows that the effects of combined exposure to different types of particles may surpass the effects anticipated by the effects of the individual particulates. These combinatory effects between types of particles could have implications when assessing measures to reduce PM-induced health effects.

Stable 3D particle manipulation using rotating elliptical Gauss–Schell model vortex partially coherent light sources

The Partially coherent light source can be applied to the noninvasive capture of particles, and increasing the freedom of capturing different types of particles simultaneously is of great significance. This paper studies the optical field distribution of a rotating elliptical Gaussian-Schell model vortex beam focused by a lens and the radiation force acting on Rayleigh particles. The beam’s rotation parameter, the vortex’s topological charge, and the spatial coherence length have different effects on the light intensity, which will determine the optical capture ability of Rayleigh particles with other refractive indices and generate equilibrium points at different positions. The longitudinal equilibrium points of high-refractive-index particles and the transverse equilibrium points of low-refractive-index particles are increased by adjusting the value of the rotation parameter and the topological charge. Finally, the appropriate size range for trapping Rayleigh particles is analyzed according to the comparison of Brownian force and radiant force. The results show that this partially coherent light source has a high degree of freedom in capturing particles with different refractive indices, which provides a new way for optical capture technology and three-dimensional (3D) particle manipulation.

Radiation and Emission Phenomena in Combination

Radiation and Emission Phenomena in Combination

直线振动筛筛面倾角对荞麦分级效果影响的模拟研究

In the buckwheat industry, buckwheat sizing effect has played a significant role in the subsequent hulling effect and food quality in its deep processing. In order to study the influence of inclination angle of linear vibrating screen on buckwheat sizing effect, EDEM was used for numerical simulation of sizing process with the inclination angle of the screen separately at 2°, 3°, 4°, and 5°. By observing particle distribution on the screen deck and calculating the different types of particles in various statistical areas, qualitative comparison and quantitative analysis on the conveying capability of the screen and the penetrating capability of particles at different inclination angles were made, and the results revealed that with the increase in the inclination angle of the screen, the conveying capability of the screen was enhanced, while particles became less capable of penetrating through the sieve. When the inclination angle was increased from 2° to 3°, the conveying capability of the screen was significantly improved, while the penetrating capability of particles on both screen decks was slightly reduced. By taking the penetrating capability of particles and the conveying capability of the screen into comprehensive consideration, it turned out that better sizing effect would be achieved at the inclination angle of 3o. Our research will provide a reference for optimizing the processing parameters during the vibrating separation of buckwheat.

In-cloud scavenging of chemically segregated particle types by individual particle observation

While aerosol plays a significant role in the formation of cloud, the in-cloud scavenging of chemically segregated particle types were still insufficiently investigated and the controlling factors remain ambiguous. Several field observations were carried out during 2018–2021 at Mt. Tianjing (1690 m a.s.l.) in southern China, based on ground-based counterflow virtual impactor (GCVI)-single particle aerosol mass spectrometer (SPAMS), to investigate the in-cloud scavenging (activation) of various particle types, including black carbon (BC), organic-containing particles (OC), mineral dust (Dust), metal-containing particles (Metal), potassium-rich particles (K-rich) and sea salt (SS). GCVI was used to sample cloud droplet residual particles (Res) while PM2.5 inlet sampled interstitial particles (Inter) during cloud events and ambient particles (Amb) on sunny days, respectively. Different types of particles were recognized based on spectral characteristics obtained by the SPAMS. Based on the coupled GCVI-SPAMS measurements, the number-based scavenging efficiencies (NSEs) of various particle types could be quantified. Besides, the influence of liquid water content (LWC), PM2.5, particle size, and mixing state on the NSEs were discussed. The NSE of SS was the highest (32.4%) while OC showed the lowest NSE (9.1%). Other particle types shared similar NSEs with all the detected particles, with an average of ∼20–25%. Apart from OC, NSEs of other types of particles increased with the increase of LWC and decreased with the increase of the concentration of PM2.5, suggesting that numerous PM2.5 suppressed particles entering cloud droplets via competing for water vapor. The annual variations of NSEs were generally in accordance with LWC and PM2.5, reflecting the certain role of these environment conditions. The NSEs typically increased with particle size in a range of 0.2–2.0 μm, reflecting the dominant nucleation mechanism during in-cloud scavenging. Particles mixed with sulfate and nitrate were easier to be scavenged than those coated with organic compounds, e.g., the discrepancy reached 11.8% for the K-rich particles.

Morphological and functional characterization of the oyster Crassostrea gasar circulating hemocytes: Cell types and phagocytosis activity

Hemocytes are the circulating cells of the hemolymph of oysters and are responsible for numerous physiological functions, including immune defense. The oyster Crassostrea gasar is a native species inhabiting mangrove habitat and is of great commercial interest, cultured throughout the Brazilian coast, mainly in the north and northeast. Despite its commercial importance, little is known about its immunological aspects and defense cells, the hemocytes. This work aimed to morphologically characterize hemocytes of the oyster C. gasar and to study one of the main cellular defense response, phagocytosis, using light microscopy and flow cytometry. The results showed the presence of six hemocyte populations in C. gasar hemolymph. These comprise of large and small granulocytes, large and small hyalinocytes, blast-like cells and a rare type classified as vesicular or serous hemocytes. Hyalinocytes were highly abundant and the most heterogeneous cell population, while small granulocytes, along with vesicular hemocytes were the less abundant population. Hemocytes of C. gasar oysters demonstrated capabilities to phagocytose three different types of particles tested: zymosan A, latex particles and Escherichia coli, indicating a broad defense capacity. The zymosan A were the most engulfed particles, followed by beads, mainly phagocytized by granulocytes, the most phagocytic cells, and finally E. coli, which were the least phagocytized. This study is the first characterization of C. gasar oyster hemocytes and will support future studies that aim to understand the participation of different hemocyte types in defense responses against pathogens and/or environmental changes.

Simulation and experimental validation of the interplay between dielectrophoretic and electroosmotic behavior of conductive and insulator particles for nanofabrication and lab-on-chip applications

In this article, we investigated the different roles of dielectrophoresis (DEP) and AC electroosmosis (ACEO) phenomena in manipulating conductive and insulator particles as future fabrication and deposition technique. A computational model was implemented using the finite element method (FEM) to better understand the interplay and velocities caused by these two electrokinetic phenomena. The simulation results showed that Carbon Nanotubes (CNTs) experience positive DEP (pDEP) up to frequencies of 1 GHz, while polystyrene (PS) particles only showed negative DEP (nDEP) regardless of the frequency. The velocity due to the ACEO was significant at the electrodes’ level at low frequencies, especially between 100 Hz and 10 kHz. The simulation results were validated experimentally, where CNTs and PS were dispersed in a medium and subjected to non-uniform electric fields. The behavior and patterns the particles formed on planner interdigitated electrodes (IDEs) match with their trajectories from the simulation. At a frequency of 1 MHz, CNTs were attracted to regions with strong electric fields, while PS particles were repelled to regions with low electric fields indicating strong pDEP and nDEP, respectively. A cloud of particles was observed at 5 kHz, indicating strong ACEO at low frequencies. This study provides a simplified and reliable technique that can be applied to manipulate different types of particles for future multilayer fabrication, thin film deposition, and lap-on-chip applications.