Ratio Of Particles Research Articles

Research on the separation chamber diameter ratio of the multi-stage hydrocyclone to inhibit particle misplacement

The particle radial settling distance is determined by the separation chamber diameter ratio of multistage hydrocyclones, affecting particle circulation flow and particle misplacement. The effect of the separation chamber diameter ratio on the flow field and separation performance is explored using numerical simulations and physical experiments. The findings indicate that a larger separation chamber diameter ratio increases the particle circulation flow ratio and coarse particle circulation flow proportion, intensifying the particle enrichment ratio. However, smaller separation chamber diameter ratios result in higher turbulence intensity and higher enrichment ratio of coarse particles in the primary separation chamber. Both oversize and undersize separation chamber diameter ratios exacerbate misplaced coarse particles. Physical test results indicate that misplaced fine particles and coarse particles diminish and eventually increase with increasing the separation chamber diameter ratio. The + 150 μm particle content in the overflow reaches the minimum value of 0.32 % in the separation chamber diameter ratio of 0.5. In comparison, the –23 μm particle content in the underflow reaches the minimum value of 3.7 % in the separation chamber diameter ratio of 0.6, and the classification efficiency of −74 μm reaches the maximum of 61.85 %. Consequently, both large and small separation chamber diameter ratios will aggravate particle misplacement and deteriorate classification performance by augmenting the coarse particle circulation flow.

Combined 100 keV Cryo-Electron Microscopy and Image Analysis Methods to Characterize the Wider Adeno-Associated Viral Products

Adeno-associated viruses (AAVs) are effective vectors for gene therapy. However, AAV drug products are inevitably contaminated with empty particles (EP), which lack a genome, owing to limitations of the purification steps. EP contamination can reduce the transduction efficiency and induce immunogenicity. Therefore, it is important to remove EPs and to determine the ratio of full genome-containing AAV particles to empty particles (F/E ratio). However, most of the existing methods fail to reliably evaluate F/E ratios that are greater than 90 %. In this study, we developed two approaches based on the image analysis of cryo-electron micrographs to determine the F/E ratios of various AAV products. Using our developed convolutional neural network (CNN) and morphological analysis, we successfully calculated the F/E ratios of various AAV products and determined the slight differences in the F/E ratios of highly purified AAV products (purity > 95 %). In addition, the F/E ratios calculated by analyzing more than 1000 AAV particles had good correlations with theoretical F/E ratios. Furthermore, the CNN reliably determined the F/E ratio with a smaller number of AAV particles than morphological analysis. Therefore, combining 100 keV cryo-EM with the developed image analysis methods enables the assessment of a wide range of AAV products.

The transformation behaviour of ZnFe2O4 spinel particles in the CaO-FexO-SiO2-ZnO slag system

Treating zinc hydrometallurgical residues and other Zn-bearing solid waste in direct lead smelting processes has been recognized as the preferred solution for the sustainable development of the lead and zinc industry. However, new technical problems occurred when changing the starting material of lead-making processes, the pyrometallurgical process for treating zinc hydrometallurgical residues and zinc bearing solid waste usually had the CaO-FexO-SiO2-ZnO slag. Along with the increasing of Zn content in the raw material, high ZnO slag formed, and the ZnFe2O4 spinel particles intended to precipitate from the molten slag. The understanding of the particle behaviour of ZnFe2O4 spinel was the core part of monitoring the slag properties. This study investigated the transformation behaviour of zinc ferrite spinel particles and the changes in glassy slag phase through the high-temperature phase equilibrium experimental technique, and the temperature was 1100 °C-1300 °C and the oxygen potential was 10−8 atm – 10−4 atm. It is found that the particle size of ZnFe2O4 spinel in the molten slag increased along with the increasing of the oxygen potential. The Zn/Fe mass ratio in spinel particles decreased when increasing of temperature and it increased when increasing of oxygen potential. The Fe/SiO2 mass ratio and the Zn content in glassy slag phase gradually increased along with increasing temperature and they decreased along with increasing oxygen potential. The growing and decomposition of ZnFe2O4 spinel was essentially a process of material exchange with the glassy slag phase.

Trapping of deformable active particles by a periodic background potential.

The dynamic behaviors, specifically trapping and sorting, of active particles interacting with periodic substrates have garnered significant attention. This study investigates numerically the trapping of soft, deformable particles on a periodic potential substrate, which can be experimentally verified through optical tweezers. The research demonstrates that multiple factors, including the relative size of traps, self-propelled velocity, shape parameters, ratio of particles to traps, and translational diffusion, can influence the trapping effect. Within certain parameter boundaries, it is shown that all particles can be consistently trapped. The research reveals that stable trapping typically occurs at median values of the relative trap size. An increase in the self-propelled velocity, the shape parameter, and the translational diffusion coefficient tends to facilitate the escapement of the particles from the traps. It is noteworthy that particles with larger shape parameters can escape even when the restoring force exceeds the self-propelled force. In addition, as the ratio of particles to traps grows, the fraction of trapped particles steadily reduces. Notably, rigid particles are consistently divided and trapped by traps closely approximating an integer multiple of the particles' area, up until the ratio reaches the aforesaid integer value. These findings can potentially enhance the understanding of the interactive effects between active deformable particles and periodic substrates. Moreover, this work suggests a different experimental approach to sort active particles based on rigidity disparities.

Functions of extracellular polymeric substances in partitioning suspended and sinking particles in the upper oceans of two open ocean systems

AbstractMarine particle dynamics and carbon export, involving extracellular polymeric substances (EPS) like transparent exopolymer particles (TEP) and Coomassie Brilliant Blue‐stained particles (CSP), are poorly understood. Although TEP adhesive properties may enhance carbon export by facilitating aggregate formation, their low density can also enhance particle suspension. Factors influencing TEP regulation of particle dynamics remain unclear. To investigate EPS contributions to particle dynamics, we investigated ratios of TEP to particulate organic carbon (POC) and of CSP to POC in suspended and sinking particles collected with marine snow catchers. Samples were collected in a subarctic region near Hokkaido during a spring phytoplankton bloom and in the oligotrophic, subtropical Kuroshio region. At Hokkaido, the mean TEP : POC ratio of sinking particles (0.075 μg Xeq. : μg C) was > 30× lower than in suspended particles (2.3), consistent with a model prediction of selective retention of buoyant TEP‐rich particles in the upper water column. In the Kuroshio region, sinking particles also contained fewer TEP than suspended particles; however, the TEP : POC ratio of sinking particles (1.0) was > 10× higher than at Hokkaido, suggesting that TEP constitute a significant carbon component of sinking particles. These findings indicate that TEP facilitate aggregation of high‐density particles and particle sinking in the Kuroshio region. Distributions of CSP : POC ratios between suspended and sinking particles resembled TEP : POC ratios in both regions, implying a significant contribution of CSP to particle dynamics. We propose that EPS have divergent effects on suspension and sinking of marine particles, which vary with particle composition and biogeochemical conditions.

Real-time evaluation of the blending uniformity of industrially produced gravelly soil based on Cond-YOLOv8-seg

Industrial production of gravelly soil has been applied at construction sites in earth-rock engineering, which adopts automatic blending and belt-conveyer systems for gravelly soil. The blending uniformity of gravelly soil has a significant impact on its mechanical and physical properties including shear resistance and impermeability. Real-time evaluation of blending uniformity is key to controlling the quality of gravelly soil. This study proposes a real-time evaluation method for the blending uniformity of gravelly soil transported by a belt conveyor. First, Cond-YOLOv8-seg is adapted to accurately segment gravel particles from gravelly soil images, employing a conditional convolution segmentation head and an improved Protonet embedded with a recurrent criss-cross attention (RCCA) module based on YOLOv8-seg. Then, the segmented masks are used to analyze the spatial uniformity (SU) and blending ratio consistency (BRC) of individual and continuous gravelly soil images, employing the proposed evaluation criterion for SU based on the theory of deformable four-sided static distances and BRC based on the area ratio of different-scale gravel particles in one image. Cond-YOLOv8-seg achieved an AP50 of 0.803 and FPS of 58.3. The effectiveness of the proposed evaluation criteria is validated quantitatively. The average uniformity evaluation time of a 2048 × 1536 image is determined to be 0.1151s, which is close to the real-time evaluation of gravelly soil transported by a belt conveyor.

Dynamic analysis on an asymmetric spatial dumbbell-type model

The structural symmetric breaking of the spatial structure will enhance the coupling dynamic behaviors and bring new challenges for the dynamic analysis on the spatial structure inevitably. The main contribution of this paper is proposing a structure-preserving iteration method to investigate the effects of the dynamic symmetry-breaking factors on the dynamic behaviors of the rigid-flexible coupling systems. Firstly, the spatial flexible damping beam assembled with two particles on both ends is simplified as an asymmetric spatial dumbbell-type model. For this model, the coupling dynamic equations are presented based on the Hamiltonian variational principle. Then, connecting the symplectic precise integration method for the ordinary differential equations mainly controlling the plane motion of the model and the generalized multi-symplectic scheme for the partial differential equation mainly controlling the transverse vibration of the beam, a structure-preserving numerical iteration method is proposed, which provides a new way to analysis the dynamic behaviors of the coupling problems with the symmetric breaking. Finally, the effects of the absolute mass and the mass ratio of the additional particles on the orbit radius, the orbit true anomaly velocity, the attitude angle velocity of the model and the transverse vibration of the flexible beam are reproduced by using the structure-preserving numerical iteration method in the numerical simulations. Particularly, the effects of the additional particles on the attitude stability of the model and the vibration dissipation of the flexible damping beam are investigated, which gives some guidance for the attitude adjustment strategy and the vibration control method for the spatial flexible structure with the structural symmetric breaking.

Tribological, corrosion, mechanical, and metallurgical behavior of clay and Al2O3-reinforced aluminum-based composite material

Aluminum-based composite materials have garnered considerable attention in recent years owing to their outstanding mechanical and tribological properties. The integration of clay and Al2O3 into the aluminum matrix has notably elevated its tribological, corrosion, mechanical, and metallurgical characteristics. An examination of the metallurgical properties involved a thorough analysis of the material's microstructure and wettability. Notably, the composite material demonstrated enhanced wettability and a more uniformly distributed reinforcement, leading to improved mechanical attributes when incorporating 5% alumina and 5% clay particles. This composition resulted in heightened strength, improved hardness, and increased fatigue strength. Specifically, the addition of a mixture of ball-milled 5% alumina and 5% clay particles led to substantial improvements, with tensile strength, hardness, and fatigue strength increasing by approximately 40.49%, 44.11%, and 62.15%, respectively. However, this enhancement came at the cost of reduced toughness in aluminum, decreasing by about 46.66% following the addition of the ball-milled mixture. Tribological assessments, involving wear tests under varying loads and speeds, demonstrated that the inclusion of 5% clay and 5% Al2O3 substantially improved wear resistance. Furthermore, corrosion resistance was evaluated, revealing that the composite material exhibited enhanced corrosion resistance attributed to the passivation of the surface. Altogether, these findings underscore the promising potential of aluminum-based composite materials for various applications, particularly when tailored with specific ratios of alumina and clay particles.

NH4Cl-assisted synthesis of TaON nanoparticle applied to photocatalytic hydrogen and oxygen evolution from water

Oxynitride semiconductors are promising photocatalyst materials for visible light-driven water splitting, while the synthesis of well crystalized oxynitride still remains challenge. In present work, narrow-bandgap TaON nanoparticles are synthesized via heating a vacuum-sealed mixture of KTaO3, Ta and NH4Cl. This method possesses multiple advantages in terms of lower calcination parameter, higher N conversion efficiency and superior photocatalytic activity in comparison with the traditional thermal ammonolysis using NH3 gas as a nitrogen source. Through the analysis of intermediates produced upon the elevation of heating temperature, a gas–solid-phase reaction between TaCl5 and Ta2O5 is demonstrated as the final step, which is conducive to decreasing thermal energy barrier and accelerating nitridation process. Precise control of preparation conditions, including calcination temperature and duration, allows for the regulation of surface O/N ratio of TaON particles to unity, resulting in optimized photocatalytic activity. Photoelectrochemical assessment and intensity modulated photocurrent spectroscopy provide convincing evidence for improved charge transfer efficiency of photoexcited holes at TaON surface. A Z-scheme overall water splitting is accomplished by employing the TaON as an effective oxygen evolution photocatalyst, SrTiO3:Rh as a hydrogen evolution photocatalyst, and reduced graphene oxide (rGO) as a solid-state electron mediator. This work presents a promising strategy for the synthesis of high-quality oxynitride materials in application to photocatalytic water splitting.

Surface Embedded Metal Nanowire-Liquid Metal-Elastomer Hybrid Composites for Stretchable Electronics.

Both liquid metal (LM) and metallic filler-based conductive composites are promising stretchable conductors. LM alloys exhibit intrinsically high deformability but present challenges for patterning on polymeric substrates due to high surface tension. On the other hand, conductive composites comprising metallic fillers undergo considerable decrease in electrical conductivity under mechanical deformation. To address the challenges, we present silver nanowire (AgNW)-LM-elastomer hybrid composite films, where AgNWs and LM are embedded below the surface of an elastomeric matrix, using two fabrication approaches, sequential and mixed. We investigate and understand the process-structure-property relationship of the AgNW-LM-elastomer hybrid composites fabricated using two approaches. Different weight ratios of AgNWs and LM particles provide tunable electrical conductivity. The hybrid composites show more stable electromechanical performance than the composites with AgNWs alone. In particular, 1:2.4 (AgNW:LMP w/w) sequential hybrid composite shows electromechanical stability similar to that of the LM-elastomer composite, with a resistance increase of 2.04% at 90% strain. The sequential approach is found to form AgIn2 intermetallic compounds which along with Ga-In bonds, imparts large deformability to the sequential hybrid composite as well as mechanical robustness against scratching, cutting, peeling, and wiping. To demonstrate the application of the hybrid composite for stretchable electronics, a laser patterned stretchable heater on textile and a stretchable circuit including a light-emitting diode are fabricated.

Industrialized fine physical regeneration process and economic benefit assessment for recycling waste HDPE containers

The production of waste HDPE containers is enormous, and its recycling and utilization is an inevitable trend to achieve sustainable social development. However, the engineering practice of recycling waste HDPE containers is still lacking. This study provides a detailed explanation of the principles of fine recycling for waste HDPE containers, and develops a set of physical regeneration processes. By combining visual recognition assisted sorting, alkali hot water washing, physical sorting, and regranulation processes, high-quality regenerated HDPE particles are prepared. Meanwhile, various real data (sample size 50–100) of the production line and products are tracked, statistically analyzed. The results show that regenerated HDPE particles have good physical properties, the ratio of HDPE particles containing aluminum foil and multicolored impurities are extremely low, and the ratio of HDPE particles containing black spots (d＞0.1 mm) is less than 1.61 × 10−2 wt% (mean). Economic benefit analysis shows that the gross profit of recycled HDPE particles is USD $312.05 per ton. The above conclusions prove the feasibility and progressiveness of this process for the regeneration of waste HDPE containers. Meanwhile, this study provides engineering technical guidance for the large-scale fine recycling and regeneration of waste HDPE containers.

Preparation and performance of alumina/epoxy-siloxane composites: A comparative study on thermal- and photo-curing process

Although epoxy-based composites that consist of inorganic fillers and matrixes are widely used in “conventional” electronic packaging applications due to their excellent insulation and robust properties, they limit their uses in “advanced electronic packaging” which requires enhanced thermal conductivity. However, conventional thermal curing methods for fabrication of epoxy-based composites do not fulfill sufficient thermal conductivity. Herein, we apply photo-induced curing strategy for fabricating alumina-incorporated epoxy-siloxane composites that consist of sol-gel derived siloxane matrix and bimodal sized alumina particles as a thermally conductive filler. We investigate how curing mechanism (thermal- or UV-curing) and varying the ratios of the alumina particles of two different sizes affect the various physical properties. It is found that photo-curing process makes greatly enhanced thermal conductivity, low thermal expansion, and high mechanical robustness compared to thermally-cured composites. As the results, we can achieve significantly enhanced thermal conductivity (>11 W/m K) with high thermal stability and mechanical robustness.

Analysis of initial stage of liquid-phase sintering by combined multi-phase-field/discrete-element method

A combined multi-phase-field/discrete-element method in two dimensions is applied to the liquid phase sintering process of blended elemental powders. The boundary migration, diffusion of elements, and phase transformation between two dissimilar particles are calculated using a multi-phase-field method for sintering based on Gibbs energy functions. The sintering shrinkage is computed with the discrete-element method taking account of the neck size and sintering force, which are obtained from a multi-phase-field simulation. In this study, a pair or small cluster consisting of two elemental powders in a binary eutectic alloy is used as a model system. First, the formation of a liquid phase around the contact area between two dissimilar particles above the eutectic temperature of the system, and the motions of the particles due to grain boundary sliding along the liquid films are confirmed. Second, an Sn–Bi system is selected as the real eutectic system, and the sintering behavior of powder compacts with various mixing ratios of Sn and Bi particles is demonstrated. Finally, transient liquid-phase sintering of Sn–Bi system is simulated, that is, the generation and extinction of the liquid phase due to interdiffusion between Sn and Bi particles are calculated.

Influence of aspect ratio of ellipsoidal particles on mixing in vibrated packed bed using discrete element method

AbstractThe uniform mixing of particles is crucial in many industrial applications. In industries, most granular materials are nonspherical, with ellipsoids being a common deviation from the sphere. The study employs the DEM model to investigate the mixing of a binary mixture in a vibrated packed bed with fixed amplitude and frequency. The study explores the behavior of the binary mixture of coarse and fine particles, with one particle being ellipsoid of aspect ratios (0.25–3.0) and the other being a sphere. The subdomain mixing index quantifies the mixing. The mixing of binary mixtures is determined by the aspect ratio of coarse and fine particles. The mixing efficiency is indicated by the average velocity of reference spherical particles, reflecting the convection strength within the bed. The results show higher average velocity in an ellipsoidal‐sphere mixture than in a sphere‐sphere mixture. The DEM results are validated with an identical experimental system.

Research on enhancement of screening performance of a novel drum screen based on the Discrete Element Method simulation

Screening is one of the most basic technologies for size classification of granular materials. Based on discrete element method simulations, a new built-in component was developed to address the problems of particle piling and poor segregation in drum screening process, and the particle dynamics and spatial distribution were carefully investigated. The results showed that, increasing the blade length will enhance the particle spreading, and a gap between the rotating blade end and the screen wall can lead to proper size segregation; Built-in slits can act as a ‘secondary screen’ by changing the volume ratio of large and small particles, and the curved-end blades can not only push the particles forward but also exert pressure on the ones underneath them; The screening efficiency changes non-linearly with the change in baffles' height; Contrastively, the screening efficiency of the optimized built-in component drum screen is significantly increased up to 82.34%.

Measurement of the charge-to-mass ratio of particles trapped by the Paul trap for education

Paul traps are devices that confine particles using an alternating electric field and have been used in undergraduate experimental classes at universities. Owing to the requirement of a high voltage ( > 103 V), Paul traps are not used in middle and high schools. Therefore, we developed an all-in-one-type Paul trap, including a high-voltage transformer. The Paul trap can be equipped with two different types of electrode attachments, ring-type and linear-type, and the trap image can be observed using a built-in web camera. For example, the charge-to-mass ratio of particles was measured with different types of attachments, and reasonable values were obtained. These types of trap devices are currently used at several educational facilities in Japan.

Quantitative Analysis of the Physical Properties of Ti6Al4V Powders Used in a Powder Bed Fusion Based on 3D X-ray Computed Tomography Images.

The physical properties of Ti6Al4V powder affect the spreadability of the powder and uniformity of the powder bed, which had a great impact on the performance of built parts made by powder bed fusion technology. Micro-computed tomography is a well-established technique used to analyze the non-destructivity of the objects' interior. Ti6Al4V powders were scanned with micro-CT to show the internal and external information of all the particles. The morphology, particle size distribution, hollow particle ratio, density, inclusion, and specific surface area of the powder samples were quantitatively characterized, and the relationship of flowability with these physical properties was analyzed in this work. The research results of this article showed that micro-CT is an effective way to characterize these items, and can be developed as a standard method of powder physical properties in the future.

Effect of additive type and amount on structural and mechanical properties of ZrO2/B4C/Al2O3/SiC added Al 1050 based composite structures produced by vacuum infiltration—Comparative study

With this experimental study, ZrO2/B4C/Al2O3/SiC ceramics in different weight ratios were added to 99.5% pure aluminum and composites were produced by vacuum infiltration, which is very rare in the literature. It is aimed to investigate how different ceramics will affect the technical properties of an aluminum composite. First, scanning electron microscope images were taken to examine their microstructures, and energy-dispersive x-ray spectroscopy analyses were performed. In addition, x-ray diffraction analyses of phase structures were performed. Then, the densities of the composite structures were measured. In the last stage of the experiments, hardness measurement, bending strength, and abrasive wear amount tests were carried out to determine the mechanical properties of the composite structures. According to the data obtained, a relatively homogeneous structure was obtained up to 10% of the ceramic particles in the structure. It was observed that thermal damage did not occur in the composite structures and no significant phase changes occurred. The highest infiltration distance was obtained from B4C-reinforced samples, and the lowest infiltration distances were obtained from ZrO2-reinforced samples. Ceramic reinforcement elements have reduced the density values of composite structures. With the increase in the ratio of ceramic reinforcement particles, the hardness values of the composites increased and the flexural strength values decreased. In the abrasive wear tests, the least wear loss was obtained from SiC-reinforced samples and the highest wear loss was obtained from ZrO2-reinforced samples. When the composites were evaluated according to their microstructure and mechanical strength, the best results were obtained with SiC and then Al2O3, B4C, and ZrO2 reinforcements, respectively. It has been concluded that SiC, Al2O3, B4C, and ZrO2 reinforcement elements in Al 1050-based composites produced by vacuum infiltration have a positive effect on most of the mechanical properties and a negative effect on some of them.

Performance of blockboard using particle composite bagasse waste as core layer materials

Using wood as the core blockboard material has affected forest exploration, which causes damage to the ecosystem and the environment. The availability of large amounts of bagasse and styrofoam waste has become a potential alternative to replace wood. This study evaluates the properties of blockboards made from a composite of bagasse waste particles as the core layer, combined with thin plywood as the face layers, and styrofoam waste as the matrix for the bagasse particle composites. The blockboards were prepared through cold compression, and the effects of particles size and the ratio of particles to styrofoam on physical and mechanical properties such as density, moisture content, water resistance, bending strength, internal bond, and screw withdrawal resistance were investigated. The results demonstrated a linear improvement in both physical and mechanical properties with an increase in styrofoam content and a decrease in the particle size of bagasse. The blockboard with fine particles and 70 wt % of styrofoam exhibited the highest density of 0.59 g/cm3, moisture content of 8.54%, water absorption resistance of 33.71%, bending strength of 11.88 MPa, internal bond of 0.64 MPa, and screw withdrawal of 823.36 N. An increase in the density of the core layer was found to enhance all physical and mechanical properties of the blockboard. Consequently, the blockboard produced exhibits the potential to serve as an alternative to traditional blockboards.

Polyethylene Glycol as Surface Modification of Magnetite Nanoparticle Coated Silica a Potentially Hyperthermia Therapy Material

Local hyperthermia therapy is one of the cancer treatments by implementing heat from a temperature of 41-45°C on cancer cells. This method is believed to reduce the risk of normal cells around the cancer cells from dying. The form of hyperthermia therapy itself is in ferrofluid. During its development, superparamagnetic nanoparticles of iron oxide have attracted various studies because of their good magnetic properties and good biocompatibility. However, the poor particle interactions and their tendency to aggregation make coatings on superparamagnetic necessary. Therefore, silica coating on the superparamagnetic surface is carried out to reduce the risk of aggregation and increase the biocompatibility of the material. Polyethylene glycol functionalization was also applied to improve the biocompatibility of the material, as well as being a carrier for ferrofluid. The test was carried out using the magnetite co-precipitation synthesis method and the formation of a sol-gel silica coating. Variations applied in this experiment are the effects of TEOS concentration as a source of silica and the ratio of particles to PEG. The addition of silica was proven to increase the value of the magnetic moment to 51.55 emu/g. The addition of TEOS as a source of silica in iron (III) nanoparticles has an effect on increasing the magnetic attraction, decreasing the surface tension value, reducing particle size, and decreasing the SAR value. Functionalization of polyethylene glycol has the effect of reducing the magnetic moment, increasing and decreasing hydrophobicity, increasing the surface tension value, and reducing the particle size of iron (III) oxide nanoparticles. This shows that magnetic nanoparticles coated with silica with polyethylene glycol functionalization are proven to generate heat when given AC current with the SAR value and the highest temperature is found in iron (III) oxide which gets 3ml silica coating with a PEG ratio of 2:5 at a temperature of 32.2°C. and SAR value of 87.63 W/mg