Mixed Particles Research Articles

Light dark matter constraints from SuperCDMS HVeV detectors operated underground with an anticoincidence event selection

This article presents constraints on dark-matter-electron interactions obtained from the first underground data-taking campaign with multiple SuperCDMS HVeV detectors operated in the same housing. An exposure of 7.63 g−days is used to set upper limits on the dark-matter-electron scattering cross section for dark matter masses between 0.5 and 1000 MeV/c2, as well as upper limits on dark photon kinetic mixing and axionlike particle axioelectric coupling for masses between 1.2 and 23.3 eV/c2. Compared to an earlier HVeV search, sensitivity was improved as a result of an increased overburden of 225 meters of water equivalent, an anticoincidence event selection, and better pile-up rejection. In the case of dark-matter-electron scattering via a heavy mediator, an improvement by up to a factor of 25 in cross section sensitivity was achieved. Published by the American Physical Society 2025

Simultaneous measurement of particle size distribution and mixing ratio based on Monte Carlo ultrasonic attenuation model

Abstract Mixed particle systems are commonly employed in industrial processes, where the characterization of particle size parameters and mixing ratio can frequently serve as key indicators in process control and production optimization. A Monte Carlo (MC) model was developed to numerically predict and study the ultrasonic attenuation spectrum characteristics in the polymethyl methacrylate (PMMA)-glass aqueous suspension, and together with the particle swarm optimization (PSO) algorithm, to handle the inverse problem in solving the particle size, distribution width, and mixing ratio. The results of the numerical simulations indicate that there exists a linear relationship between the attenuation coefficient and the mixing ratio, with the particle size exerting a significant influence. Furthermore, the multi-parameter simultaneous inversion also yielded calculation deviations of less than 1%, 3%, and 6% for the mixing ratio, characteristic diameter, and distribution width, respectively, in comparison to their given values. Afterward, a series of experiments were conducted to quantify the particle size and mixing ratio through the analysis of ultrasonic spectra. In spherical PMMA-glass aqueous suspensions, the measurement error for the mixing ratio and particle size parameters are found to be less than 7% and 10%, respectively, when compared to the image method and the given values. Nevertheless, the measurement errors are slightly increased in a non-spherical mixed particle system, where the volume median diameter and mixing ratio are still less than 10%. The MC modeling and PSO algorithm offer the potential to characterize particle size and mixing ratio for mixed particle systems in industrial applications.

Preparation of a Silicon/MXene Composite Electrode by a High-Pressure Forming Method and Its Application in Li+-Ion Storage

The main component of high-capacity silicon-based electrodes is silicon powder, which necessitates intricate processing to minimize volume growth and powder separation while guaranteeing the ideal Si content. This work uses the an situ high-pressure forming approach to create an MXene/m-Si/MXene composite electrode, where MXene refers to Ti3C2TX, and m-Si denotes two-phase mixed nano-Si particles. The sandwich shape promotes silicon’s volume growth and stops active particles from spreading. The conductive structure of Ti3C2TX MXene increases the efficiency of charge transfer while reducing internal resistance. After 100 cycles, the composite electrode’s original capacity of 1310.9 mAh g−1 at a current density of 0.5 A g−1 is maintained at 781.0 mAh g−1. These findings lay the foundation for further investigations into Si matrix composite electrodes.

In Situ Tracking of Nanoparticles During Electrophoresis in Hydrogels Using a Fiber-Based UV-Vis System

Gel electrophoresis is a powerful method for the separation of nanoparticulate suspensions into several fractions with distinct particle properties. To monitor particle migration through the three-dimensional net structure of the gel and gain insights about the separation process, this study introduces a self-designed fiber-based UV-Vis measurement system equipped with five probes for the sequential in situ recording of absorption spectra. The system was employed to investigate the migration and separation of Au and Fe3O4 particles within hydrogels of varying agarose concentrations (0.15–0.50 wt.-%), revealing an increase in scattering with higher agarose content. The identification of specific particle fractions with a spherical or rod-shaped morphology was successfully achieved within the gels due to characteristic absorption peaks, allowing the real-time observation of particle separation. For the separation of a binary mixture, an adequate migration distance is needed according to the difference in the electrophoretic mobility of the two samples. The particle tracking and an additional mathematical deconvolution allowed the analysis of mixed particle samples within the gel so that their weight ratio could be determined. Finally, the system was calibrated for the determination of the particle concentration within the gel matrix, quantitatively revealing the particle concentration at a specific position in the gel.

YOLO-PAS: Detection of Mixed Impurity Particles in Transformer Oil Based on Lens-Free Holographic Imaging and Improved YOLO

YOLO-PAS: Detection of Mixed Impurity Particles in Transformer Oil Based on Lens-Free Holographic Imaging and Improved YOLO

Observational constraint on momentum flux-gradient relationships reduces modeling biases of PBL mixing of particles in urban area

Abstract The momentum flux-gradient relationships within the urban roughness sublayer deviate from the classical relationships proposed by the Monin-Obukhov similarity theory. Despite this discrepancy, prevailing atmospheric models persistently rely on these classical relationships, which were originally derived from natural, homogeneous surfaces. This practice may introduce significant errors when simulating urban atmospheric pollution. This study utilized meteorological parameters and turbulent fluxes obtained from field measurements in the urban roughness sublayer to re-establish momentum flux-gradient relationships. Compared to non-urban areas, the flux-gradient relationships in the urban environments exhibit significant deviations under stable conditions. Consequently, we revised a planetary boundary layer parameterization to incorporate new urban flux-gradient relationships. The revised scheme was implemented in the WRF-Chem model, and the simulation results demonstrated a marked reduction in modeling biases under stable conditions, particularly for relatively developed cities in Eastern China.

Mixing Performance Analysis of a Planetary Concrete Mixer

In this research, the discrete element method is employed to study the mixing performance of a 1m3 capacity planetary concrete mixer. The performance was evaluated based on the homogeneity of granular particle mixing and the scanning of the mixer’s inside by the gyrational and planetary mixing blades. The granular particle mixing was realized by applying the Hertz-Mindlin contact law, constant directional torque, and the Simplified Johnson-Kendall-Roberts (SJKR) models using open-source software. Furthermore, analytical formulations for the trajectories of mixing blades were developed and implemented in MATLAB. The trajectories were plotted at various time intervals, and it was observed that the entire mixer was fully scanned in approximately 30 seconds. Finally, numerical and analytical results were compared to verify the findings.

Elucidating Extracellular Vesicle Isolation Kinetics via an Integrated Off-Stoichiometry Thiol-Ene and Cyclic Olefin Copolymer Microfluidic Device.

Extracellular vesicles (EVs) are promising biomarkers for diagnosing complex diseases such as cancer and neurodegenerative disorders. Yet, their clinical application is hindered by challenges in isolating cancer-derived EVs efficiently due to their broad size distribution in biological samples. This study introduces a microfluidic device fabricated using off-stoichiometry thiol-ene and cyclic olefin copolymer, addressing the absorption limitations of polydimethylsiloxane (PDMS). The device streamlines a standard laboratory assay into a semi-automated microfluidic chip, integrating sample mixing and magnetic particle separation. Using the microfluidic device, the binding kinetics between EVs and anti-CD9 nanobodies were measured for the first time. Based on the binding kinetics, already after 10 min the EV capture was saturated and comparable to standard laboratory assays, offering a faster alternative to antibody-based immunomagnetic protocols. Furthermore, this study reveals the binding kinetics of EVs to anti-CD9 nanobodies for the first time. Our findings demonstrate the potential of the microfluidic device to enhance clinical diagnostics by offering speed and reducing manual labor without compromising accuracy.

Biomimetic Alumina Film for Passive Daytime Radiative Cooling.

Passive daytime radiative cooling is receiving more and more attention as a cooling method that does not consume energy to cool objects. However, most radiative cooling materials require the mixing of multiple particles, which increases the manufacturing process requirements. Most radiative cooling materials are susceptible to outdoor abrasion, pollution, and UV exposure, which leads to decreased performance. In this paper, the biomimetic film with both radiative cooling and self-cleaning functions was prepared by a simple evaporation-induced self-assembly process and spraying process using Al2O3 as the main radiatively cooling raw material, poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF-HFP)] as the additive, and polydimethylsiloxane as the binder. Therefore, we can get a biomimetic-Al2O3-P(VDF-HFP)-PDMS film (BAPPF). The BAPPF was spectrally selective. Specifically, the reflectance of BAPPF in the solar spectrum (0.45-0.89 μm) exceeded 100%, and the average reflectance in the main thermal effect of the solar spectrum (0.78-1.10 μm) was 99.92%. In addition, the BAPPF had 96.97% reflectance in the solar spectrum (0.3-2.5 μm) and 90.55% mid-infrared emissivity in the atmospheric window (8-13 μm). The combined performance enabled BAPPF to reduce temperature by up to 8.4 °C over air temperature in outdoor tests. What's more, BAPPF had excellent superhydrophobic properties, with a water contact angle of up to 159°. The self-cleaning of the BAPPF prevented contamination and maintained cooling even when working outdoors for long periods of time. Furthermore, the BAPPF maintained high performance after mechanical friction, chemical corrosion, UV aging, and water impact, which has broad reference value and application prospects.

Update in association between Lung Cancer and air pollution.

A significant portion of newly diagnosed lung cancer cases occur in populations exposed to air pollution. The World Health Organization has identified air pollution as a human carcinogen, prompting many countries to implement monitoring systems for ambient particulate matter (PM). PM consists of a complex mix of organic and inorganic particles, both solid and liquid, present in the air. Given the carcinogenic properties of PM and the prevalence of lung cancer in exposed populations, it is crucial to explore their connection and clinical implications to effectively prevent lung cancer in this group. This review examines the link between ambient PM and lung cancer. Epidemiological studies have shown a dose-response relationship between PM exposure and lung cancer risk. PM exposure leads to oxidative stress, disrupting the body's redox balance and causing DNA damage, a key factor in cancer development. Recent findings on the strong correlation between ambient PM and adenocarcinoma suggest that understanding the specific molecular and pathological background of pollution-related lung cancer is important. In addition to efforts to control emission sources at the international level, a more individualized approach is necessary to prevent PM-related lung cancer development.

A Method for Aliasing Metal Particle Recognition Based on Three-Coil Sensor Using Frequency Conversion

The diesel engine on a ship is crucial as it serves as the primary power source, significantly influencing both the vessel’s efficiency and safety. Monitoring metal wear particles found in lubricating oil is essential for assessing the lubrication condition of mechanical equipment onboard and anticipating potential failures. Analyzing these metal wear particles allows us to gauge the wear status of bearing pairs within the machinery, thereby providing a technical foundation for routine maintenance activities. However, under real operating conditions, it can be challenging to prevent multiple metal particles from simultaneously passing through sensors. To address this issue, this research introduces an innovative three-coil induction sensor that employs a variable-frequency excitation technique to explore how induction and eddy currents interact. The findings indicate that when the excitation frequency changes, the peak value of the signal from 337 μm iron particles only increases by 3.35 times, while the peak value of the signal from 340 μm copper particles increases by 22.69 times. Consequently, this study recommends using changes in excitation frequency to differentiate between mixed metal particles made of various materials.

Effect of the Cross-Sectional Geometry of the Mixed Particle Zone on the Spiral Separation Process and Its Structural Optimization

Cross-sectional geometry is of significance in determining the flow characteristics and the particles separation in spiral concentrators. The effects of the cross-sectional geometry within the mixed particle zone on the secondary flow and the separation process of hematite and quartz particles with a size of 89.5 μm were investigated via a computational fluid dynamics (CFD) approach. The optimization of the line segment slopes was conducted using response surface methodology (RSM). The results indicate that the peak radial fluxes and average radial velocities of the secondary flow are positively correlated with the corresponding line segment slope. The independent adjustment of line slopes in regions I and II, and the interaction of line slopes in regions I and III, influence the separation efficiency of hematite and quartz particles significantly. The separation performance of the experimental spiral concentrator with a cross-sectional profile of the optimized line segments for a feed of hematite and quartz with a size range of −100 + 75 μm is remarkably improved by nearly 5%. This study provides insights for the cross-section design of spiral concentrators for the effective separation of coarse-grained hematite and quartz.

Viscosity of aqueous ammonium nitrate–organic particles: equilibrium partitioning may be a reasonable assumption for most tropospheric conditions

Abstract. The viscosity of aerosol particles determines the critical mixing time of gas–particle partitioning of volatile compounds in the atmosphere. The partitioning of the semi-volatile ammonium nitrate (NH4NO3) might alter the viscosity of highly viscous secondary organic aerosol particles during their lifetimes. In contrast to the viscosity of organic particles, data on the viscosity of internally mixed inorganic–organic aerosol particles are scarce. We determined the viscosity of an aqueous ternary inorganic–organic system consisting of NH4NO3 and a proxy compound for a highly viscous organic, sucrose. Three techniques were applied to cover the atmospherically relevant humidity range: viscometry, fluorescence recovery after photobleaching, and the poke-flow technique. We show that the viscosity of NH4NO3–sucrose–H2O with an organic to inorganic dry mass ratio of 4:1 is 4 orders of magnitude lower than the viscosity of the aqueous sucrose under low-humidity conditions (30 % relative humidity (RH), 293 K). By comparing viscosity predictions of mixing rules with those of the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients Viscosity (AIOMFAC-VISC) model, we found that a mixing rule based on mole fractions performs similarly when data from corresponding binary aqueous subsystems are available. Applying this mixing rule, we estimated the characteristic internal mixing time of aerosol particles, indicating significantly faster mixing for inorganic–organic mixtures compared to electrolyte-free particles, especially at lower RH. Hence, the assumption in global atmospheric chemistry models of quasi-instantaneous equilibrium gas–particle partitioning is reasonable for internally mixed single-phase particles containing dissolved electrolytes (but not necessarily for phase-separated particles), for most conditions in the planetary boundary layer. Further data are needed to see whether this assumption holds for the entire troposphere at midlatitudes and at RH > 35 %.

A mixed total Lagrangian-updated Lagrangian Smoothed Particles Hydrodynamics method for geomechanics simulations with discontinuities

This study presents a novel approach for simulating geotechnical problems including the initiation and post-failure behavior of discontinuities. The developed method is constituted by a mixed total Lagrangian--updated Lagrangian Smoothed Particle Hydrodynamics (SPH) method, which the main characteristic is to distinguish between internal forces within a body and contact forces from interactions with other bodies as internal stress and collision stress, respectively. Internal stress effects are calculated using total Lagrangian SPH interpolations, while collision stress effects are computed with updated Lagrangian. Fractures are simulated by employing plastic deformation as a damage measure, with fully damaged particles detached from their original body and treated as a separate particulate material, interacting via collision stress. Numerical tests confirm the method's capability in accurately modeling elastic collisions, friction forces and tension and shear fractures, validated against experimental data. Finally, we show the applicability of the proposed by simulating a real-scale landslide scenario, the Selborne experiment. This final numerical test demonstrates the capability of the method to simulate a landslide detached from the main soil mass as observed in the experiment.

Fabrication of superhydrophobic transparent coatings prepared by spraying dual-sized silica particles

Abstract Photovoltaic modules exposed to severe wind and sand conditions over extended periods often accumulate dust, significantly impacting their power generation efficiency. Superhydrophobic self-cleaning coatings present a promising solution to mitigate this issue. In this study, a SiO2/PU coating was applied to glass substrates using a combined sol–gel spraying technique. The sol system comprised a mixture of SiO2 particles with diameters of 20 nm and 200 nm, enabling the construction of a micro-nano structure that enhances surface hydrophobicity. The SiO2/PU coatings prepared with mixed particle sizes demonstrated significant improvements in contact angle, rolling angle, self-cleaning, and antifouling properties compared to those made with a single particle size, achieving a water contact angle of 164.52°. Furthermore, the prepared SiO2/PU coatings possess excellent stability and transmittance. It is anticipated that this superhydrophobic SiO2/PU coating will be a candidate for anti- dust applications in photovoltaic modules.

Influence of threaded pipe structural parameters on the conveyance of lithium-ion battery anode materials

Particle stratification occurs during the pneumatic conveyance of lithium-ion battery (LIB) anode materials, resulting in an uneven particle size distribution, which affects battery performance. To optimize the conveyance of lithium-ion battery anode material particles and achieve uniform mixing of large and small particles, this study proposes the inclusion of a threaded pipe section and evaluates this structure based on numerical simulations and experimental research. The results indicate that a pitch of 500 mm maximizes the mixing performance enhancement coefficient for the threaded pipe section. Additionally, the mixing performance is best for a channel comprising 4 threaded pipe sections (the enhancement coefficient exceeds 1.6). The final structure with 4 threaded pipe sections, 500 mm pitch, and 4 channels can be used for graphitic anodes in LIBs under conditions of a small pressure drop and excellent mixing performance. This structure also provides uniform particle transportation.

Regulatory mechanism and applicability of pulsed gas on drying uniformity of non-spherical wet grains in a fluidized-bed

Pulsed gas can regulate the uniform fluidization of particles, thereby enhancing the product quality of wet grains after drying. However, due to the diversity of grain shapes, the regulatory mechanism and applicability of pulsed gas on the drying uniformity of grains remain unclear. This study used an improved CFD-DEM drying model for wet grains to investigate how particle shape and pulsed frequency affect flow, heat transfer, and mass transfer. The results showed that increasing pulsed frequency can transition the particle mixing mechanism from convective to diffusive, and reduce the particle residence time in high-temperature regions. The formation frequency of horizontal channel-like bubbles influences the mesoscale structure evolution and interphase heat transfer uniformity. However, higher pulsed frequency decreases contact time between particles and bubbles, requiring a balance between mixing intensity and bubble contact. Finally, the intercriteria correlation method quantified the applicability of pulsed frequency for drying particles with different shapes.

Upgrading Mixed Plastic Waste through Industrial Symbiosis: Pseudoductile Regenerated Cellulose Fiber-Reinforced Shredder Residue Composites.

The mechanical performance of mixed plastic waste from shredder residue is hindered by brittleness and catastrophic failure, limiting its potential applications. In this study, the mechanical properties of mixed plastic is enhanced by reinforcement with rayon fibers through a wet powder impregnation process to leverage the fiber's ductility and entanglement. However, mixed plastic remains poorly dispersed in water during the composite manufacturing, resulting in poorly consolidated composite, which further deteriorates the mechanical properties of mixed plastic from 1.5% strain-at-break to 0.7%. To address this issue, the addition of sodium dodecyl sulfate (SDS) surfactant is explored, where the optimal concentration is found beyond the critical micelle concentration at 10 mM. Lowering the surface tension of water and the adsorption of the SDS on the mixed plastic powder surface facilitated homogeneous dispersion of mixed plastic particles, resulting in well-consolidated rayon fiber-reinforced composites. The 30 wt % rayon fiber-reinforced mixed plastic composite prepared with SDS demonstrated a progressive failure behavior, exhibiting a strain-at-break of 8% and a remarkable 350% increase in impact strength compared to unreinforced mixed plastic. This approach provides a platform to overcome the inherent limitations of mixed plastic waste, offering waste-derived plastic alternatives and reducing the need for fossil-derived virgin materials for a wide range of noncritical applications.

Acoustofluidic tweezers via ring resonance.

Ring resonator (RR) devices are closed-loop waveguides where waves circulate only at the resonant frequencies. They have been used in sensor technology and optical tweezers, but controlling micron-scale particles with optical RR tweezers is challenging due to insufficient force, short working distances, and photodamage. To overcome these obstacles, an acoustofluidic RR-based tweezing method is developed to manipulate micro-sized particles that can enhance particle trapping through the resonance interaction of acoustic waves with high Q factor (>3000), more than 20 times greater than traditional acoustic transducers. Particles can be precisely manipulated within the RR by adjusting the signal phase, with trapping amplified by enlarging the connected waveguide. Rapid particle mixing is achieved when particles are placed between the waveguide and RR. The signal path is strengthened by strategically positioning the RR in a two-dimensional plane. Acoustofluidic RR tweezers have immense potential for advancing applications in biosensing, mechanobiology, lab-on-a-chip, and cell-cell communication research.

Osmotic and phoretic competition explains chemotaxic assembly and sorting

Microscale objects responding to chemical gradients by migrating toward or away from a preferred species is a simple yet constitutive mechanism by which transport occurs in biological organisms. Synthetic chemotaxis provides key physical descriptions of simplified systems that can be used in biological models, or in the creation of advanced responsive material systems. In this article, we provide a quantitative framework for understanding synthetic chemotaxis of microparticles which involves a competition between phoresis and osmosis. We present separate quantitative measurements of phoresis and osmosis acting on individual taxing particles, finding that phoresis follows the long-predicted [Formula: see text] scaling while the osmotic contribution depends on the geometry and details of the system, and must be solved on a case-by-case basis. Through this, we are able to develop a more accurate picture of particle transport at the single particle level. Equipped with this approach, we go on to describe how high concentrations of particles in a symmetric chemical gradient grow close-packed hives that reach a steady-state size tunable through light intensity or particle size. Last, we demonstrate that mixed particles experiencing the same chemical gradient will selectively migrate toward or away depending on the nature of the particle surface, thereby locally sorting out a particular species. We anticipate these results will be important in describing both biological and synthetic chemotaxis in phoretic systems and should bring a wealth of studies that take advantage of competing osmotic flows to illicit unexpected dynamic active behavior.