Particle Concentration Research Articles

Application of an inertial vacuum trap for separation of the solid phase of carbon dioxide from the flow of fuel combustion products of boiler units

The technological process of low-temperature purification of fuel combustion products of boiler units from carbon dioxide by freezing it in a turboexpander and separating from the fuel combustion products flow in a separator is considered.The issue of separation of solid carbon dioxide from the flow of fuel combustion products of boiler units using a bag filter, an electric precipitator, a cyclone separator and an inertia-type separator is considered. Based on the analysis, the use of an inertial vacuum separator for separating the solid phase of carbon dioxide from the flow of fuel combustion products is proposed.Solidworks and ANSYS CFX modules were used for numerical modeling. To solve, the equations of continuity, motion, energy, and the k-ε model equations are used. The closing equation is for the effective and turbulent viscosity. There is also a description of the forces affecting the movement of the dispersed phase. The stream is considered lightly dusty.Numerical studies of the dispersed flow in the channel of an inertial-vacuum separator and in the previously used cyclone TsN-11 were carried out. The initial data for the calculation were taken based on the known mass flow rate and particle concentration, as well as from the continuity equation. From the results obtained, we can draw conclusions about a directly proportional relationship between the growth of the flow rate characteristics of the flow, the speeds along the flow path of the apparatus at the inlet and the resistance of the apparatus.Besides, based on the obtained calculation results, it was concluded that it is necessary to additionally install a rotary industrial air blower in order to create the necessary pressure drop in the inertial vacuum separator. The economic and environmental feasibility of installing a rotary air blower is consideredThe range of consumption of fuel combustion products has been determined at which the most effective purification of fuel combustion products from carbon dioxide in an inertial vacuum separator is possible within the technical characteristics of the refrigeration capacity of turborefrigeration machines.

Bending motion induced by near-infrared laser irradiation of polymer films made by UV-curable liquid crystalline monomer containing gold-coated fine particles

Polymer films made by UV-curable liquid crystalline (LC) monomer have both characters of the external stimulus responsiveness of LC and flexibility of polymer chains. Therefore, polymer film made by UV-curable LC monomer are expected as soft actuators. By incorporating photothermal conversion materials in polymer film, the macro shape of film can be controlled by light irradiation. In this study, a polymer film made by UV-curable LC monomer containing gold-coated fine particles was prepared and its bending motion induced by near-infrared laser irradiation was studied. When the film is irradiated with near-infrared laser, it bends. We also investigated the dependence of the concentration and distribution of gold-coated fine particles in the film, and irradiation time and intensity for the bending displacement.

Measurement of Aerosol Particles from Vibrated Lab Coats.

A study was conducted to measure aerosol particles emitted from laboratory coats (lab coats) under vibration, comparing them with a suit and a shirt. This study focused on particles ranging from 0.3 μm to >10 μm. Experimental results showed that lab coat vibration increased particles >5 μm while reducing submicron particles. The lab coat (old and used) exhibited greater particle concentration variations under vibration compared to those using the new lab coat or the shirt. Contrastingly, the suit under vibration did not significantly affect particle concentrations. These findings highlight the impact of lab coat vibration on aerosol particle concentrations in the surrounding air, which is important for work environments.

Plastic particles and fluorescent brightener co-modify Chlorella pyrenoidosa photosynthesis and a machine learning approach predict algae growth

Global release of plastics exerts various impacts on the ecological cycle, particularly on primary photosynthesis, while the impacts of plastic additives are unknown. As a carrier of fluorescent brightener, plastic particles co-modify Chlorella pyrenoidosa (C. pyrenoidosa) growth and its photosynthetic parameters. In general, adding to the oxidative damage induced by polystyrene, fluorescent brightener-doped polystyrene produces stronger visible light and the amount of negative charge is more likely to cause photodamage in C. pyrenoidosa leading to higher energy dissipation through conditioning than in the control group with a date of ETR (II) inhibition rate of 33 %, Fv/Fm inhibition rate of 8.3 % and Pm inhibition rate of 48.8 %. To elucidate the ecological effect of fluorescent brightener doping in plastic particles, a machine learning method is performed to establish a Gradient Boosting Machine model for predicting the impact of environmental factors on algal growth. Upon validation, the model achieved an average fitting degree of 88 %. Relative concentration of plastic particles and algae claimed the most significant factor by interpretability analysis of the machine learning. Additionally, both Gradient Boosting Machine prediction and experimental results indicate a matching result that plastic additives have an inhibitive effect on algal growth.

Amphiphilic Janus Particles for Aerobic Alcohol Oxidation in Oil Foams.

Amphiphilic Janus silica particles, tunable with oleophobic-oleophilic properties and low fluorine content (8 wt % F), exhibited prominent foamability for a variety of aromatic alcohols at low particle concentrations (<1 wt %) compared to randomly functionalized silica particles. When selectively loaded with Pd nanoparticles on the oleophilic hemisphere, the particles displayed more than a 2-fold increase in catalytic activity for the aerobic oxidation of benzyl alcohol compared to nonfoam bulk catalysis under ambient O2 pressure. The particles were conveniently recycled with high foamability and catalytic activity maintained for at least five consecutive runs.

Rheology and electrorheological effects of waxy oils with different carbon number distribution

High-voltage electric treatment is an emerging technology for enhancing the cold flowability of crude oil. The primary mechanism involves the accumulation of charged particles (resins and asphaltenes) onto wax particles under the electric field. This electrorheological effect varies with different oil compositions. We have investigated the impact of resins and asphaltenes on the electrorheological behaviors of waxy oils. However, the impact of the carbon number distribution of wax on this effect remains unexplored. Therefore, the objective of this work is to investigate the interaction between waxes with various carbon numbers and charged particles and its impact on the electrorheological behaviors of waxy oils. Model waxy oils containing distinct wax fractions (paraffin and microcrystalline waxes) and varying charged particle concentrations were prepared and studied. The results unveiled that microcrystalline wax model oils exhibited substantial reductions in viscosity and yield stress after electric treatment, up to 80% and 60%, respectively, surpassing the improvements observed in paraffin wax model oils which were less than 50%. This disparity is attributed to the better capacity of resins and asphaltenes to be eutectic with paraffin wax, improving the original flowability of paraffin wax model oil, thus involving fewer charged particles in the interaction with wax under electric treatment, resulting in a weakened electrorheological effect. Resins and asphaltenes struggle to form eutectic mixtures with microcrystalline wax, resulting in minimal flowability improvement of microcrystalline wax model oils by charged particles. Consequently, under the electric field, a substantial proportion of free resins and asphaltenes can interact with microcrystalline wax particles, leading to superior electrorheological effects in microcrystalline wax model oils.

Online detection method for magnetic suspension concentration based on machine vision

Abstract With the intelligent development of magnetic particle inspection, the quality of magnetic indications formed at cracks is closely related to the accuracy of magnetic particle inspection image analysis results. The concentration of magnetic suspension is a key process parameter affecting the quality of magnetic indication formation. Hence, this study presents an online detection method based on machine vision for measuring magnetic suspension concentration. The method initially enhances the contrast of images of the pear-shaped measuring tube containing magnetic suspension and then extracts scale lines through feature analysis and morphological processing. A method for extracting the magnetic particle sedimentation area of magnetic suspension based on a dual-threshold segmentation algorithm is proposed. The contour filtering algorithm and pixel calibration method are used to obtain the magnetic particle concentration of the non-estimation and estimation areas based on scale line extraction, ultimately forming an online accurate detection method for magnetic suspension concentration values. Experiments were conducted to validate the method against different concentrations, turbidity levels, tilting angles of the pear-shaped measuring tube, and ambient brightness. The results show that the error in magnetic suspension concentration detection based on this method is within ±3%. This has certain reference value for the stable control of magnetic suspension concentration and for enhancing the reliability of intelligent decision-making results in magnetic particle inspection.&amp;#xD;

Improving color uniformity and the ambient contrast ratio of LEDs through the scattering-enhanced magnetic manipulation bilayered structure

To address challenges in enhancing color uniformity and ambient contrast ratio (ACR) in RGB light-emitting diodes (LEDs) without losing efficiency, we developed a scattering-enhanced magnetic manipulation (SEMM) bilayer structure. The effect of the TiO2 scattering layer on improving the LED’s angular intensity non-uniformity (AIN) was studied by ray-tracing simulations and optimized by varying the particle concentration. The magnetic manipulation technique formed the microcolumns and magnetic chains of the Fe3O4 anti-reflective layer, which was optimized by adjusting Fe3O4 particle size, magnetic field strength, and Fe3O4 concentration. The resulting bilayered device significantly increased the ACR by 11.38 times and reduced AIN by 63% compared to conventional graphite-based LEDs, while maintaining high brightness and consistent color quality across angles. This marks a pioneering application of magnetic manipulation in enhancing LED display quality.

Numerical simulation of pressure loss and flow characteristics in combined elbow pipes for solid-liquid two-phase flow.

The transport of solid-liquid two-phase flow is widely used in water conservancy, environmental protection, and municipal engineering. Accurate pressure loss calculation is crucial for hydraulic transport pipelines, particularly in the case of bends, valves, and other deformation parts. These factors directly impact the energy consumption and the investment of the system. This paper employed the Euler-Euler multiphase flow model to investigate the characteristics of solid-liquid two-phase flow in vertically positioned combined elbows. The model was initially validated using data from the literature. Subsequently, based on the validated model, an investigation was conducted to determine the relationship between pressure loss and various factors, including flow velocity, combined angle, particle concentration, and particle size. Finally, the changes in velocity distribution, particle concentration, and turbulent kinetic energy were analyzed. The results indicate that the pressure loss increases with the flow velocity, tends to decrease with the combined angle, and increases with the particle concentration. The relationship between pressure loss and particle size is more complex. The velocity distribution, particle concentration, and turbulent kinetic energy exhibit the variations caused by different factors.

Reorganization of Snowfall beneath Cloud Top within the Comma Head Region of Two Extreme U.S. East Coast Winter Cyclones

Abstract This paper examines ice particle reorganization by three-dimensional horizontal kinematic flows within the comma head regions of two U.S. East Coast winter storms and the effect of reorganization on particle concentrations within snowbands in each storm. In these simplified experiments, the kinematic flows are from the initialization of the HRRR model. Ice particles falling through the comma head were started from either 9-, 8-, or 7-km altitude, spaced every 200 m, and were transported north or northwest, arriving within the north or northwest half of the primary snowband in each storm. The greatest particle concentration enhancement within each band was a factor of 2.32–3.84 for the 16–17 December 2020 storm and 1.76–2.32 for the 29–30 January 2022 storm. Trajectory analyses for particles originating at 4 km on the southeast side of the comma head beneath the dry slot showed that this region supplied particles to the south side of the band with particle enhancements of factor of 1.36–2.08 for the 16–17 December 2020 storm and 1.04–2.16 for the 29–30 January 2022 storm. Snowfall within the bands had two source regions: 1) on the north/northwestern side, from ice particles falling from the comma head, and 2) on the southeastern side, from particles forming at or below 4-km altitude and transported northwestward by low-level flow off the Atlantic. While the findings give information on the source of particles in the bands, they do not definitively determine the cause of precipitation banding since other factors, such as large-scale ascent and embedded convection, also contribute to snow growth. Significance Statement Wintertime storms along the east coast of North America can produce heavy snowfall, high winds, coastal flooding, and cold temperatures, resulting in major economic impacts within the northeast U.S. urban corridor. The heaviest snowfall typically occurs within snowbands, elongated narrow regions identifiable by high reflectivity on radar. This paper examines the potential sources of the ice particles contributing to the snowbands and how the flow fields throughout the storm can contribute to enhanced particle concentrations within the bands.

Understanding the impact of combined hydrodynamic shear and interfacial dilatational stress, on interface-mediated particle formation for monoclonal antibody formulations

During biomanufacturing, several unit operations expose solutions of biologics to multiple stresses, such as hydrodynamic shear forces due to fluid flow and interfacial dilatational stresses due to mechanical agitation or bubble collapse. When these stresses individually act on proteins adsorbed to interfaces, it results in an increase in protein particles in the bulk solution, a phenomenon referred to as interface-induced protein particle formation. However, an understanding of the dominant cause, when multiple stresses are acting simultaneously or sequentially, on interface-induced protein particle formation is limited. In this work, we established a unique set-up using a peristaltic pump and a Langmuir-Pockels trough to study the impact of hydrodynamic shear stress due to pumping and interfacial dilatational stress, on protein particle formation. Our experimental results together demonstrate that for protein solutions subjected to various combinations of stress (i.e., interfacial and hydrodynamic stress in different sequences), surface pressure values during adsorption and when subjected to compression/dilatational stresses, showed no change, suggesting that the interfacial properties of the protein film are not impacted by pumping. The concentration of protein particles is an order of magnitude higher when interfacial dilatational stress is applied at the air-liquid interface, compared to solutions that are only subjected to pumping. Furthermore, the order in which these stresses are applied, have a significant impact on the concentration of protein particles measured in the bulk solution. Together, these studies conclude that for biologics exposed to multiple stresses throughout bioprocessing and manufacturing, exposure to air-liquid interfacial dilatational stress is the predominant mechanism impacting protein particle formation at the interface and in the bulk solution.

COVID-19 lockdown impact on air quality and associated health benefit in two contrasting urban cities in Eastern Indo Gangetic Plain

A key challenge in controlling deteriorating urban air quality is a lack of clear understanding of the regional emissions characteristics and their impact on human health. COVID-19 lockdown provided an opportunity to enhance understanding of background air quality. Towards this, we studied the effect of the lockdown on air pollutants level and associated health benefits in two contrasting urban cities of Eastern IGP, Asansol (industrial) and Kolkata (metropolitan), by analyzing data from 2019 to 2021. The outcomes revealed that the level of exceedance of air pollutants is usually higher in Asansol but significantly decreased in both cities during the lockdown period. Particle concentrations were reduced by 50–70 % compared to Pre-Lockdown and by 20–35 % against the same period in 2019. Kolkata witnessed a higher reduction in PM levels than Asansol. Diurnal variation comparison showed a higher reduction of particle levels during lockdown in the morning at Asansol while in the evening at Kolkata. The health benefits associated with the reduction in PM2.5 concentration were quantified using the BenMAP-CE model, which revealed that improving air quality, like during the lockdown period, would save annually 0.46 and 2.91 deaths per 100,000 persons in Asansol and Kolkata, respectively. Altogether, this study's outcomes provide essential insights to policymakers for regional factors associated to varying air quality and health benefits associated to improvement in air quality.

Rhizaria in the oligotrophic ocean exhibit clear temporal and vertical variability

Recently studies have shown that Rhizaria, a super-group of marine protists, have a large role in pelagic ecosystems. They are unique in that they construct mineral tests out of silica, calcium carbonate, or strontium sulfate. As a consequence, Rhizaria can have large impacts on the ocean’s cycling of carbon and other elements. However, less is known about Rhizaria ecology or their role in the pelagic food-web. Some taxa, like certain Radiolarians, are mixotrophic, hosting algal symbionts. While other taxa are flux-feeders or even predatory carnivores. Some prior research has suggested that Rhizaria will partition vertically in the water column, likely due to different trophic strategies. However, very few studies have investigated their populations over extended periods of time. In this study, we present data investigating Rhizaria abundance and vertical distribution from over a year of monthly cruises in the Sargasso Sea. This study represents the first quantification of Rhizaria throughout the mesopelagic zone in an oligotrophic system for an extended period of time. We use this data to investigate the hypothesis that Rhizaria taxonomic groups will partition due to trophic mode. We also investigate how their abundance varies in accordance with environmental parameters. Rhizaria abundance was quantified using an Underwater Vision Profiler (UVP5), an in-situ imaging device. Ultimately, we show that different Rhizaria taxa will have unique vertical distribution patterns. Models relating their abundance to environmental parameters have mixed results, yet particle concentration is a common predictive variable, supporting the importance of heterotrophy amongst many taxa.

Effects of cavitation and erosion on submersible drainage pumps: A numerical study

Submersible drainage pumps are used around the world both residentially and industrially for draining water and sewage. However, these pumps are prone to wear and clogging when the flows inward contain particles and air bubbles, and the combined effects of cavitation and erosion directly affect the performance of such pumps and degrade their efficiency. Therefore, it is essential to design a submersible pump that mitigates the adverse effects of cavitation and erosion. Reported here is an energy-efficient submersible drainage pump for use in emergency response. The combined cavitation–erosion effects are established in order to reduce their adverse impact on the pump, and how erosion wear affects the cavitation characteristics of the water in the pump is investigated. An experiment was conducted to verify the numerical results pump, and then, the influences of particle concentration and size on two-stage existing and altered model submersible pumps were analyzed using computational fluid dynamics. The results show that the performance of the altered model pump increased by 4.34%, with the cavitation–erosion effects reduced significantly. In addition, higher particle concentration induced higher erosion rates at both the leading and trailing edges of the impeller blades. Furthermore, the altered model significantly reduced the cavitation–erosion impact on the pump impeller blades compared to the existing model.

3D printing of pickering emulsion gels of protein particles prepared by high pressure homogenization and heating

In this study, oil-in-water Pickering emulsion gels stabilized by soybean protein isolate microgel particles were prepared by a combination of high pressure homogenization and heating. These particles swiftly adsorbed onto the oil-water interface stabilizing drops. Cryo-SEM showed the formation of small droplets wrapped in a three-dimensional network structure of protein particles. Heating and increasing the oil content and particle concentration can improve the viscosity, energy storage modulus and gel strength of the system, which is conducive to improving the ability to 3D print these emulsions. The shear-thinning properties allow the system to be extruded smoothly through the nozzle with good printability. When the oil content was 60%, the accuracy and stability of the printed modeling reached 91.8% and 97.2%, respectively. In the future, the excellent properties of Pickering emulsion gel can be further utilized to load active ingredients, optimize and adjust the taste, and prepare food suitable for the elderly and other people with swallowing disorders with the help of 3D printing technology, and achieve the delivery of precise nutrition.

CeO2/SWCNT nanocomposite coating: A novel approach for corrosion application

AbstractThe coatings were prepared by blending different concentrations of SWCNTs and CeO2 particles with an epoxy resin by hydrothermal method, which was then applied to the substrate through the doctor blade technique. The mixtures were transferred into a 1‐L capacity autoclave with a teflon‐lined flange type and subjected to hydrothermal treatment at 100°C for 3 h. The surface coatings were applied using a doctor blade. Subsequently, the coated materials were placed in an oven and dried for 12 h at 50°C under vacuum conditions. The samples' structural analysis was examined through x‐ray diffraction (XRD). XRD analysis verified the CeO2/SWCNT composite coating, and Fourier transform infrared spectroscopy (FTIR) was utilized to assess the presence of functional groups. Thermodynamic properties and thermal stability of composite coatings that were modified with SWCNTs and CeO2 particles were studied by thermogravimetric analysis (TGA). The impact of the CeO2/SWCNT composite on the anticorrosion capabilities of the epoxy coating was examined through electrochemical impedance spectroscopy (EIS), Nyquist curve, and Tafel slope characterization. Corrosion tests were conducted on the CeO2/SWCNT composite coatings in a 3.5 wt% sodium chloride (NaCl) solution at 25°C to improve corrosion resistance. The concentration of 0.4 wt% CeO2 was found to be optimal for achieving effective corrosion resistance. The composite coating CNT0.6‐C0.4 exhibited significantly higher Ecorr (−426 V) and lower Icorr (2.96 × 10−6 A cm−2) values compared to samples from the CNT0, CNT0.2, and CNT0.6 groups. The paper presents a viable solution with CeO2/SWCNT composite coating for the engineering application of corrosive‐inhibiting coatings.

Experimental study of sediment erosion in Francis runner using a non-recirculating test rig

Abstract The problem of sediment erosion in hydraulic turbines has posed challenges in design, operation and maintenance of hydraulic machinery. A study was conducted with a 2 kW model Francis runner for investigating the erosion prone locations. The runner and guide vanes were coated with four different coats of colour (red, yellow, green, and blue). The system was then operated in sediment-laden condition with an average concentration of sediment particles of about 24000 ppm. The runner was operated in sediment-laden conditions for 36 hours and the observations were made after each 4 hours of operation. With increasing hours of operation, the colour coating of the runner was eroded at specific locations and a pattern was revealed showing the areas affected by erosion. The erosion was mostly observed at the trailing edge of the pressure side and the junction of the suction side of the blade and hub. Erosion on the hub was observed towards the leading edge of the runner in the area close to the suction side and the region near the trailing edge of blade. Similarly, the guide vanes were eroded at the pressure side of the leading edge and the trailing edge of the suction side. The causes of erosion were identified as high velocity and acceleration of sediment particles, inter-blade vortex, and vortex due to leakage flow.

Exploring the tendency of Brownian agglomeration in polydispersed systems of solid atmospheric aerosols

Recent extensive research has focused on atmospheric aerosol systems, driven by their far-reaching implications for climate and public health, with a goal to identify optimal air quality management practices. This study employs Langevin dynamics to investigate the impact of size distribution and concentration of submicrometer solid aerosol particles on Brownian agglomeration tendencies within an isothermal, hydrostatically balanced atmosphere. To accomplish this, a Langevin dynamic model is devised, and parameters are carefully determined to ensure numerical integration precision, stability, and efficiency. Using this model, we numerically simulate the average agglomeration nucleus and overall agglomeration rate within the system while considering variations in the standard deviation of size distribution and volume fraction of aerosol particles.

Numerical investigation of proppant transportation characteristics in hydraulically fractured wedge fractures

Hydraulic fracturing creates multiple induced fractures and micro-fractures, forming a complex fracture network in the reservoir. The study of the transport and distribution of the proppant within the fracture network is critical to the design and evaluation. However, existing simulation studies of proppant transport tend to be overly idealized and neglect the inhomogeneity of fracture widths that occur after fracturing. To address these issues, this study employs computational fluid dynamics (CFD) to study the transportation of fracturing fluid and proppant within a fracture network. The flow dynamics of solid-liquid two-phase flow in fractures are simulated using the Euler-Euler multiphase flow model. Considering the actual variables in field construction and the inherent inhomogeneity in realistic fracture structures, a three-dimensional model was established to capture the gradual variation in fracture width. The accuracy of this model was verified through a comparative analysis with physical experiments. On this basis, an investigation was conducted to explore the impact of particle size, particle density, particle volume concentration, and injection velocity on proppant transportation. The results demonstrate that, in contrast to conventional rectangular fractures, sandbanks formed from wedge fractures exhibit a lower height, which facilitates improved transportation into deeper fractures. Furthermore, particle concentration primarily influences distal fractures, with proppant particle size being second. The injection velocity has a significant impact on the height of the sandbank located in proximity to the fracture inlet. The research findings provide a deeper understanding of the transport and distribution of proppants within wedge fractures, thereby establishing a theoretical basis for the analysis and engineering guidance in on-site hydraulic fracturing construction.

Visualization experiment on dynamic migration and sealing mechanism of irregular materials in rough fractures

Lost circulation is one of the main problems causing low drilling efficiency and high drilling costs in the oil and gas industry. Due to an insufficient understanding of the migration and sealing mechanism of lost circulation materials (LCMs) in rough fractures, the success of fracture sealing is highly unpredictable. This study conducted visualization experiments using four types of LCMs to observe the entire dynamic sealing process of rough fractures. Adaptive fracture sealing experiments were designed to improve the sealing performance of LCMs at low concentrations. The results indicated that the key to sealing rough fractures is forming an effective sealing zone inside the fracture space rather than in the inlet buffer zone. The dynamic sealing process has experienced four typical stages: sporadic bridging, bridging structure expansion, sealing front formation, and sealing layer thickening. The first three typical stages correspond to flow from plate flow to trench flow and seepage. The formation of an effective sealing zone within fractures depends on forming a practical sealing front and subsequent particle accumulation of LCMs that thicken the sealing layer. Compared with regular particles, the sealing front of irregular particles is an area with a specific aperture range. The increase in irregular particle concentration makes the sealing front migrate to the fracture entrance, which is more likely to lead to inlet blockage. The distribution of a sealing zone depends upon the surface morphology of rough fracture. Increasing the particle size distribution improves the favorable bridging area and enhances the sealing performance. The adaptive sealing strategy uses low-concentration granular materials to form multi-point bridging within rough fractures and low-concentration flaky materials to adaptively and quickly extend and connect dispersed bridging structures. Mica flakes are more conducive to extending along the contour of fracture aperture than calcium carbonate particles. Adding mica flakes promotes the expansion of the bridging structures, forming a sealing front and a robust sealing layer in advance. This study delves into irregular materials' migration and sealing mechanisms in rough fractures, enriching theoretical understanding and providing guidance for on-site sealing operations.