Particle Size Distribution Of Material Research Articles

Identifying the influence of inlet velocity changes to pressure drop and collecting efficiency in Stairmand and Lapple type cyclone separators

The object of this research is to compare the performance of Stairmand and Lapple type cyclone separators. The main problem to be solved in this research is determining which Stairmand or Lapple type cyclone separator is more suitable for integration into the pyrolysis system. The comparison is based on key performance indicators: pressure drop and collecting efficiency. The research findings indicate that both Stairmand and Lapple cyclone separators exhibit similar trends in pressure drop and collecting efficiency. As inlet velocity increases, the pressure drop also increases for both types. However, the collecting efficiency initially rises but then declines when inlet velocities exceed 13 m/s. The Lapple variant achieved a peak collecting efficiency of 98.94 % and pressure drop 16.26 mbar at an inlet velocity of 13 m/s, whereas the Stairmand design reached 97.33 % and pressure drop 12.16 mbar at 13 m/s inlet velocity. The Lapple type cyclone separator outperformed the Stairmand type in terms of both of pressure drop and collecting efficiency. This superiority is attributed to the specific design features and characteristics of the Lapple type. The superior performance of the Lapple type cyclone separator can be explained by its unique design elements that contribute to improved particulate matter separation and pressure drop. These elements may include differences in cylinder height and particulate matter outlet diameter. Based on the findings of this research, the Lapple type cyclone separator is recommended for integration into pyrolysis systems. However, it is important to consider the specific operating conditions of the pyrolysis process, such as temperature, the particulate matter size distribution, flow rate, and desired separation efficiency

Size-resolved particulate matter inside selected fire stations and preliminary evaluation of the effectiveness of washing machines in reducing its concentrations

The study aimed to determine and compare the mass concentration and size distribution of particulate matter (PM) at two Polish fire stations, one equipped with a washing machine intended for the decontamination of uniforms (FSN) and the other not equipped with this type of device (FSC), to assess the effectiveness of washing machines in reducing PM concentrations inside fire stations and estimate PM doses inhaled by firefighters while performing activities in truck bays and changing rooms during one work shift. The average PM concentrations at the FSN were 18.2–28.9 µg/m3 and 27.5–37.3 µg/m3, while at FSC they were 27.4–37.9 µg/m3 and 24.6–32.8 µg/m3 in the truck bays and changing rooms, respectively. At each measurement point, most of the PM mass (65–75%) was accumulated as fine particles. The dominance of fine particles in the total mass of PM results in high values of PM deposition coefficients (0.59–0.61) in three sections of the respiratory tract at each monitoring site. This study initially indicates the effectiveness of washing machines in reducing the concentration of fine particles and demonstrates the necessity, as well as directions for further research in this area.

Efficient capture of particulate matter with composite air filters comprising bamboo-derived nanofiber and base paper

Particulate-matter (PM) air filters comprising chemically synthesized polymers and petroleum-based materials are not environmentally sustainable because they do not biodegrade, causing secondary environmental pollution. To overcome this problem, we synthesized and analyzed the PM-capturing performance of composite sandwich-structured air filters containing bamboo-derived lignocellulose nanofibers and lignocellulose base paper. Bamboo pulp was produced through an organosolv process, and lignocellulose nanofibers and lignocellulose base paper were manufactured via electrospinning and paper processes, respectively. The manufacturing process was not only optimized via a rheological analysis of the precursor solution with different mixed solvent composition (6:4, 5:5, and 4:6 of 1-ethyl-3-methylimidazolium acetate:dimethylformamide) and different lignocellulose weight percent (3.3, 4.0, and 4.6 wt%), but also via nanofiber characterization, including electrospinnability, diameter distribution, and basis weight. The base paper condition was optimized based on analyses of the air permeability, PM filtration efficiency, and strength according to the paper thickness of 0.38 ± 0.05 and 0.10 ± 0.05 mm. As the lignocellulose nanofibers and base paper effectively captured particles smaller and larger than 2.5 μm, respectively, the structure of their composite sandwich-structured air filter was optimized to improve its PM-capturing performance. The study results provide new insights into the manufacturing of highly efficient PM air filters suitable for practical applications with diverse PM size distributions.

Enhanced brackish water desalination in capacitive deionization with composite Zn-BTC MOF-incorporated electrodes

In this study, composite electrodes with metal–organic framework (MOF) for brackish water desalination via capacitive deionization (CDI) were developed. The electrodes contained activated carbon (AC), polyvinylidene fluoride (PVDF), and zinc-benzene tricarboxylic acid (Zn-BTC) MOF in varying proportions, improving their electrochemical performance. Among them, the E4 electrode with 6% Zn-BTC MOF exhibited the best performance in terms of CV and EIS analyses, with a specific capacity of 88 F g−1 and low ion charge transfer resistance of 4.9 Ω. The E4 electrode showed a 46.7% increase in specific capacitance compared to the E1 electrode, which did not include the MOF. Physicochemical analyses, including XRD, FTIR, FESEM, BET, EDS, elemental mapping, and contact angle measurements, verified the superior properties of the E4 electrode compared to E1, showcasing successful MOF synthesis, desirable pore size, elemental and particle-size distribution of materials, and the superior hydrophilicity enhancement. By evaluating salt removal capacity (SRC) in various setups using an initially 100.0 mg L−1 NaCl feed solution, the asymmetric arrangement of E1 and E4 electrodes outperformed symmetric arrangements, achieving a 21.1% increase in SRC to 6.3 mg g−1. This study demonstrates the potential of MOF-incorporated electrodes for efficient CDI desalination processes.

Experimental study of particulate matter emission for a diesel engine fueled with nanoparticles and biofuel / diesel blends

There has been a lot of interest in alternative fuels due to the depletion of petroleum supplies and growing environmental concerns. Biodiesel is made from renewable resources and is one of the many practical and beneficial fuel substitutes for fossil fuels. Recent advancements in nanotechnology have made it feasible to use nanoparticles as fuel additives for internal combustion engines. An earlier study suggested that these compounds might enhance engine performance. There has been a concern that this may increase the particulate matter emitted with the exhaust which adversely affects the air quality. The size-distribution of unregulated particulate matter (PM) emitted with exhaust gases is examined in this work. Under various load conditions, PM exhaust emissions were examined while keeping the engine running at a constant 1350 rpm. A nanoparticles of 50 parts per milligram of Aluminum oxide Al2O3 and Iron oxide Fe2O3 into the jatropha biodiesel / diesel fuel blend. When the engine is fueled with blend of diesel, biodiesel, and nanoparticles ternary fuel, it created fewer particulate matter emissions than the diesel/biodiesel binary blend which contains no nanoparticles. In comparison to pure diesel fuel, the diesel/biodiesel blend binary combination produced 10–15 % less PM1, PM2.5, PM7, and PM10 emissions which is very critical to air pollution problem with the fine/very fine particles.

Spatiotemporal variations in the grain size distribution in the water column and sediments from the Yellow River Delta to distal areas under coastal currents

The differentiation of sediment grain size from large river deltas to distal areas in a coastal flow system and its evolution are vital because they greatly contribute to matter transport, pollution accumulation, and carbon cycling on the inner shelf. Here, the Yellow River sedimentary system in the adjacent seas is studied, including the proximal delta of the Yellow River and the distal mud patch. The grain size distributions of the suspended particulate matter (SPM), surface sediments, and core sediments in the Shandong Peninsula Coastal Current (SPCC) system were integrated and analyzed. The results show that apparent variations in the grain size distribution exist in the SPM and sediments in the SPCC system. The grain size distribution of the SPM near the proximal delta of the Yellow River is multimodal and variable with water depth, whereas that in the distal mud area is typically unimodal. The coarse-grained endmember of suspended sediments is restricted in the proximal area by ocean fronts under fair weather conditions in both summer and winter and is only transported to the distal mud area under strengthened coastal currents in winter. In contrast, fine-grained endmembers can be transported far away under tidal currents and coastal currents year-round. The temporal grain size variation near the proximal delta is also significantly affected by historical shifts in the Yellow River mouth, while the strength of coastal currents associated with the East Asian Winter Monsoon (EAWM) controls the grain size distribution in the distal mud area. The roles of river behaviors, ocean fronts, tides, and winds are all highlighted in the control of grain size differentiation. These results potentially have significance for understanding sediment dynamics and mass transport processes in similar coastal current systems involving large rivers worldwide.

126 Size distribution and characterization of particulate matter generated during tunnel boring machine excavation

126 Size distribution and characterization of particulate matter generated during tunnel boring machine excavation

Characterization of particle exposure during tunnel excavation by tunnel boring machines.

Tunnel boring machines (TBMs) are used to excavate tunnels in a manner where the rock is constantly penetrated with rotating cutter heads. Fine particles of the rock minerals are thereby generated. Workers on and in the vicinity of the TBM are exposed to particulate matter (PM) consisting of bedrock minerals including α-quartz. Exposure to respirable α-quartz remains a concern because of the respiratory diseases associated with this exposure. The particle size distribution of PM and α-quartz is of special importance because of its influence on adverse health effects, monitoring and control strategies as well as accurate quantification of α-quartz concentrations. The major aim of our study was therefore to investigate the particle size distribution of airborne PM and α-quartz generated during tunnel excavation using TBMs in an area dominated by gneiss, a metamorphic type of rock. Sioutas cascade impactors were used to collect personal samples on 3 separate days. The impactor fractionates the dust in 5 size fractions, from 10 µm down to below 0.25 µm. The filters were weighted, and the α-quartz concentrations were quantified using X-ray diffraction (XRD) analysis and the NIOSH 7500 method on the 5 size fractions. Other minerals were determined using Rietveld refinement XRD analysis. The size and elemental composition of individual particles were investigated by scanning electron microscopy. The majority of PM mass was collected on the first 3 stages (aerodynamic diameter = 10 to 0.5 µm) of the Sioutas cascade impactor. No observable differences were found for the size distribution of the collected PM and α-quartz for the 3 sampling days nor the various work tasks. However, the α-quartz proportion varied for the 3 sampling days demonstrating a dependence on geology. The collected α-quartz consisted of more particles with sizes below 1 µm than the calibration material, which most likely affected the accuracy of the measured respirable α-quartz concentrations. This potential systematic error is important to keep in mind when analyzing α-quartz from occupational samples. Knowledge of the particle size distribution is also important for control measures, which should target particle sizes that efficiently capture the respirable α-quartz concentration.

Fabrication of high-performance recrystallized silicon carbide ceramic membrane based on particle packing optimization

Overcoming the challenges associated with achieving high uniformity and connectivity of pore channels in ceramic membranes, we designed silicon carbide ceramic membrane derived from the recrystallization process based on the Dinger-Funk equation of the closest-packing model with various grain grading. Furthermore, the effects of particle size distribution on the resulting microstructure and pore architecture of the ceramic membrane was also explored. The findings corroborated the critical importance of raw material particle size distribution in controlling pore size distribution and morphology. After sintering at 1900°C, the silicon carbide ceramic membrane, benefiting from ideal particle packing, exhibited a remarkably uniform pore structure. Notably, the most probable pore size constituted over 70 %, while achieving an open porosity of 51.3 % even without the addition of pore-forming agents. The silicon carbide ceramic membrane also demonstrated exceptional hydrophilicity (water contact angle:∼0°), impressive water permeation (1210 L m−2 h−1·bar−1), coupled with efficient turbidity removal (∼100 %) in carbon black wastewater treatment applications. Additionally, membrane regeneration proved effective using a dilute NaOH solution backwash, achieving a flux recovery efficiency of 98 %. This strategy had directive significance for designing high-performing silicon carbide ceramic membranes.

Effect of nano-graphene lubricating oil on particulate matter of a diesel engine

Nano-graphene lubricating oil with appropriate concentration shows excellent performance in reducing friction and wear under different working conditions of diesel engines, and has been widely concerned. Lubricating oil has a significant impact on particulate matter (PM) emissions. At present, there are few studies on the impact of nano-graphene lubricating oil on the physicochemical properties of PM. In order to comprehensively evaluate the impact of nano-graphene lubricating oil on diesel engines, this paper mainly focused on the effects of lubricating oil nano-graphene additives on the particle size distribution and physicochemical properties of PM. The results show that, compared with pure lubricating oil, the total number of nuclear PM and accumulated PM of nano-graphene lubricating oil is significantly increased. The fractal dimension of PM of nano-graphene lubricating oil increases and its structure becomes more compact. The average fringe separation distance of basic carbon particles decreases, the average fringe length increases. The degree of ordering and graphitization of basic carbon particles are higher. The fringe tortuosity of basic carbon particles decreases, and the fluctuation of carbon layer structure of basic carbon particles decreases. Aliphatic substances in PM are basically unchanged, aromatic components and oxygen functional groups increase. The initial PM oxidation temperature and burnout temperature increase, the maximum oxidation rate temperature and combustion characteristic index decrease, and the activation energy increases, making it more difficult to oxidize. This was mainly caused by the higher graphitization degree of PM of nano-graphene lubricating oil and the increased content of aromatic substances.

Characteristics of fine particle formation during combustion of high-alkali coal in a new full-scale circulating fluidized bed boiler

High-alkali coal generated an increased number of fine particles during the combustion process. Understanding the transformative characteristics of particulate matter (PM) in a full-scale boiler that burns 100 % Zhundong (ZD) coal is key for controlling pollutant emissions. This paper investigated PM formation in a novel full-scale Circulating Fluidized Bed (CFB) boiler. PM samples were collected from various points along the steam-cooled flue at 50 %, 67 %, and 100 % boiler load. Utilizing Low-pressure impactors and scanning electron microscopy coupled with energy disperse spectroscopy (SEM-EDS) were applied to analyze the mass-based particle size distribution(MPSD), elemental compositions, and morphology of PM. The results show that sub-micron particles produced under low boiler load consist primarily of AAEMs sulfates, whereas under high load, they consist primarily of alkali metal chlorides. Super-micron particles are predominantly sulfates and silicates. The concentrations of Na, K, and Cl in PM0.4 decreased as the flue gas cooled down in the steam-flue of the CFB. At 100 % boiler load, Na, K, Cl and S account for more than 90 % of the total elements in the sub-micron particles. However, these four elements demonstrated a 25 % decrease at a boiler load of 67 % compared to 100 % load. Interestingly, the compositions of super-micron particles seemed to be minimally affected by the boiler load.

Characteristics of number concentration, size distribution and components of particulate matter emitted from a typical large civil airport

Civil airports are recognized as significant contributors to fine particulate matter, especially ultra-fine particulate matter (UFP). The pollutants from airport activities have a notable adverse impact on global climate, urban air quality, and public health. However, there is a lack of practical observational studies on the characterization of integrated pollutant emissions from large civil airports. This study aims to focus on the combined emission characteristics of particulate number concentration (PNC), size distribution, and components at a large civil airport, especially UFP. The findings reveal that airport activities significantly contribute to elevated PNC levels during aircraft activity in downwind conditions (four times higher than background levels) and upwind conditions (7.5 times higher). UFP dominates the PNC around the airport. The particle size distribution shows two peaks occurring around 10-30 nm and 60-80 nm. Notably, particles within the ranges of 17-29 nm and 57-101 nm account for 65.9 % and 12.0 % of the total PNC respectively. Aircraft landing has the greatest impact on particles sized between 6 and 17 nm while takeoff affects particles sized between 29 and 57 nm resulting in a respective increase in PNC by factors of approximately 3.27 and 35.4-fold increase compared to background levels. Different aircraft types exhibit varying effects on PNC with A320 and A321 showing more pronounced effects during takeoff and landing.The presence of airports leads to roughly five-fold rise in elemental component concentrations with Si being highest followed by OC, Ca, Al, Fe, Ca2+, EC, and Mg2+. The OC/EC ratio under high aircraft activity in downwind conditions falls within range of approximately 2.5–3.5. These characteristic components and ratio can be considered as identifying species for civil airports. PMF model show about 75 % of the particulate emissions at the airport boundary were related to airport activities.

Самоочищение атмосферного воздуха от пылевых частиц в условиях прибрежного морского климата

The intensity of air pollution depends on the characteristics of pollution sources, distance from the sea, terrain, density of residential buildings and the presence of a green zone. The influence of climatic conditions on the distribution of suspended particulate matter in the atmospheric surface layer of Vladivostok was studied. The aim of the study was to determine the particle size distribution of suspended particulate matter in the atmospheric surface layer and to assess the conditions for self-purification of urban air under the influence of the coastal maritime climate. The assessment of the urban air pollution with suspended particulate matter was carried out in two areas with different levels of pollution. The human breathing zone was examined. The temperature, humidity, air pressure, wind direction and speed at sampling points were determined. We used monitoring of meteorological data (dew point, wind gusts, clouds, fog) from the nearest regional meteorological stations. Statistical processing included the “Canonical Analysis” module. In the polluted area of the city the atmospheric circulation (direction, speed and gusts of wind) greatly affect the distribution of fine-dispersed particles (2.5–10.0 µm) that are hazardous to health. The impact of temperature and humidity conditions is reduced in power. The temperature and humidity regime, atmospheric pressure, cloudiness with frequent fog affect the ultrafine dust spectrum in the slightly polluted island area of the city. The above factors contribute to the enhancement of the nanoparticle nucleation process. Self-purification of the air surface layer from dust particles in both polluted and slightly polluted areas of Vladivostok is associated with the southerly winds. The monsoon maritime climate defines the air purifying in the region. The temperature and humidity regime actively affects the dust disperse composition in both sampling sites. In the island area of the city it determines the content of particles up to 10 µm; in the continental area – fractions of 0.1–50.0 µm.

Ambient particulate matter monitoring using bright field imaging-based sensor

The bright-field imaging of the particulate matter is demonstrated with the customized bright-field (BF) microscopic unit. Polystyrene spheres of size 4.5 µm as reference objects have been imaged to validate the claim. An image-processing-based algorithm has been used which uses pixel size for particle sizing and distribution. The lateral resolution of the device is found to be approximately 0.5 µm and the field of view is 56 µm × 42 µm which has been utilized for the imaging of the ambient PM. The device gives the results in the form of particulate matter concentration, size distribution, and shape of particulate matter.

Source-specific risks assessment of size-resolved PM bound multiple toxicants: Variation of source-specific risks in respiratory tracts

Inhalation risks depend on the size distribution of ambient particulate matter (PM) bound toxicants, which are influenced by various sources. This study explored variations in source-specific risks across different respiratory tract regions and their association with size-resolved toxicants. Potentially toxic elements contribute significantly, accounting for over 93% of the inhalation risk, followed by polycyclic aromatic hydrocarbons at 0.3%–7%, and organophosphate esters at less than 0.01%. For adults, the contribution of non-cancer and cancer risks within respiratory tracts was as follows: upper respiratory tract (∼61%) > pulmonary (∼30%) region > tracheobronchial (∼8%) region. Differently, for children, the order was pulmonary (∼43%) > upper respiratory tract (∼41%) > tracheobronchial (∼17%). In the adult population, resuspended dust (RD) presented elevated non-cancer risks in the upper respiratory tract compared to the tracheobronchial and pulmonary regions, while coal combustion (CC), traffic emission (TE), and waste recycling or incineration (WI) contribute most to pulmonary risks. In contrast, for children, non-cancer risk associated with CC surpassed RD in the upper respiratory tract, whereas RD exceeded CC in the tracheobronchial region. This discrepancy arises because RD primarily consists of coarse PM with higher deposition fractions in the adults' upper respiratory tract and children's tracheobronchial region, while toxicants from CC, TE and WI, with PM < 0.43 μm, are inclined to have a greater impact on the pulmonary region. Regarding source cancer risks, RD exhibited a consistent decrease across all three respiratory tract regions, with primary dominance observed in industrial emissions (IE), CC, and TE sources.

Effect of FIPs strategy and nanoparticles additives into the renewable fuel blends on NOX emissions, PM size distribution and soot oxidation in CRDI diesel engine

‏ The search of next prospective source of fuel is highlighted by the research community to compensate the aspects of shortcomings of diesel fuel and to treat the harmful emissions in the transportation sector. Among numerous economic sectors, the use of petro-diesel still the main fuel using for driving heavy machinery despite the high advance in electric motors for transportation systems. The characteristics of engine performance, nitrogen oxide (NOX) emissions, size distribution of particulate matter (PM), number and oxidation reactivity of soot particles from the effects of low and high fuel injection pressures (FIPs) and adding two types of nanoparticles (Al2O3 and TiO2) to the M20B10 blend (20 % of microalgae biodiesel, 10 % n-butanol and 70 % of diesel) were studied in common-rail diesel engine at different loads. The results revealed that the adding Al2O3 and TiO2 to the M20B10 blend decreased the BSFC by 21.28 % and 22.84 %, respectively, and also improved BTE by 4.46 % and 2.35 %, respectively, for different engine loads. It is observed that the applied HFIP and M20B10+Al2O3 blend also enhance the fuel consumption by 21.28 % and increase BTE by 9.63 % in comparison with M20B10+ TiO2 blend. In contrast, the presence HFIP with nano blends increased the NOX emissions by 24.73 % with respect to the LFIP, meanwhile the NOX emissions decreased from nano blends combustion more than to the neat M20B10 blend. The combustion of M20B10+Al2O3 blend decreased the PM concentration (by 52.82 %) and number (by 33.62 %) and when compared with blend of M20B10+ TiO2 and neat M20B10 blend combustion at HFIP. Furthermore, the reactivity of soot oxidation significantly increased when adding Al2O3 into the M20B10 blend and applying HFIP compared to the M20B10+ TiO2 blend.

A Novel Particle Size Detection System Based on RGB-Laser Fusion Segmentation With Feature Dual-Recalibration for Blast Furnace Materials

Particle size detection (PSD) is used to obtain the particle size distribution of materials in the blast furnace charging process, which is significant for optimizing the gas flow distribution and ensuring stable production. However, due to the complex surface texture of the materials and the uneven illumination of the production environment, existing methods have difficulty obtaining the particle size distribution efficiently. This paper proposes an end-to-end PSD system based on image segmentation to obtain the particle size distribution online with high accuracy. First, to further enhance the expression of edge features and reduce the interference of complex textures, an RGB-laser particle segmentation network (RLPNet) is developed to obtain high-precision segmentation images by camera-LiDAR sensor fusion. Moreover, to improve the fusion of RGB and laser features, a feature dual-recalibration (FDR) module was designed and embedded in RLPNet, consisting of independent recalibration and joint recalibration with T-convolution. Finally, to reduce the error caused by missing edge particle pixels, an edge-recognition-based particle size calculation strategy (ERP) is presented. Experimental results demonstrate that the proposed method performs well on the constructed dataset and in industrial applications. With the segmentation accuracy of RLPNet reaching 64.19 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> , the similarity between the particle size distribution predicted with ERP and the actual distribution reaches 79.19 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> .

Combustion aerosols and suspended dust with controlled processes in Lhasa: Elemental analysis and size distribution characteristics

To explore air contamination resulting from special biomass combustion and suspended dust in Lhasa, the present study focused on the size distribution and chemical characteristics of particulate matter (PM) emission resulting from 7 types of non-fossil pollution sources. We investigated the concentration and size distribution of trace elements from 7 pollution sources collected in Lhasa. Combining Lhasa's atmospheric particulate matter data, enrichment factors (EFs) have been calculated to examine the potential impact of those pollution sources on the atmosphere quality of Lhasa. The highest mass concentration of total elements of biomass combustion appeared at PM0.4, and the second highest concentration existed in the size fraction 0.4–1 µm; the higher proportion (12 %) of toxic metals was produced by biomass combustion. The elemental composition of suspended dust and atmospheric particulate matter was close (except for As and Cd); the highest concentration of elements was all noted in PM2.5-10 (PM3-10). Potassium was found to be one of the main biomass markers. The proportion of Cu in suspended dust is significantly lower than that of atmospheric particulate matter (0.53 % and 3.75 %), which indicates that there are other anthropogenic sources. The EFs analysis showed that the Cr, Cu, Zn, and Pb produced by biomass combustion were highly enriched (EFs > 100) in all particle sizes. The EFs of most trace elements increased with decreasing particle size, indicating the greater influence of humanfactors on smaller particles.

Size distribution and elemental composition of airborne particulate matter on four plant species in vertical greenery systems

Vertical greenery systems (VGSs) have been proven to greatly improve the urban thermal environment. However, their effect on the retention of airborne particulate matter (PM) in the road environment remains unclear. This study aimed to assess the quantity of size-segregated PMs on both the upper (adaxial) and lower (abaxial) leaf surfaces, the mass of size-segregated PMs on the leaf surface and within the leaf wax, as well as the elemental composition of PMs retained in leaf stomata of four plant species in VGSs in Guangzhou. The findings revealed that VGSs exhibited greater retention of fine (<2.5 μm) PMs when compared to coarse (2.5–10 μm) and large (>10 μm) PMs. Among the four species studied, Tradescantia spathacea exhibited the highest PM retention in VGSs. The number density of accumulated PMs on the upper and lower leaf surfaces of the four plant species of VGSs at three heights varied significantly with species, heights, and their interaction (P < 0.05). The greatest stomatal block rate by PM occurred at a height of 0.6 m, the range was 91.1%–98.0%. The composition of PMs retained by the leaves primarily consisted of common element of C, O, Ca, K, Mg, and Si, which likely originated from natural sources. Heavy metals (HMs) such as Cr and Cd may have originated from brakes, while Zn and Cu might be attributed to tire wear and exhaust emissions. Therefore, VGSs effectively retained a substantial quantity of airborne PM and contributed to the mitigation of urban air pollution issues.

К вопросу о гранулометрическом составе взорванных скальных пород

Decreasing ore grades combined with increasing pit depths call for the development of solutions to ensure efficient interaction within the mine-to-mill concept, which should be adapted to each specific mining operation and will optimize the production costs. The aim of the study was to develop a methodological approach to assess the particle size distribution of material within the mine-to-mill process. The study applied a comprehensive approach, which includes scientific analysis and generalization of previously published research results. From the methodological point of view, the study was based on the system analysis methods, as well as on the use of information technologies. A conclusion is made that a mathematical apparatus needs to be created and implemented, which would allow formalizing the nature of statistical data on the particle size distribution. The solution of this problem is extremely important to obtain a time series describing the dynamics of the process over time, since most of the data have a different format of representation. The authors believe that a promising approach is to use predictive analytics, i.e. a tool for analyzing statistically significant and objective data, which helps to make accurate forecasts for decisionmaking.