Dust Generation Research Articles

Hydrogen inhibition performance of blueberry anthocyanin as a green-potent inhibitor in wet Al alloy dust collector systems

To solve the fire and explosion risks caused by hydrogen generation of Al alloy dust in wet dust collector systems, an attempt is made to use blueberry anthocyanin (B-ACN), as a non-toxic and environmentally friendly inhibitor for hydrogen generation of Al alloy dust. Hydrogen inhibition effect and mechanism are evaluated through hydrogen production experiments, hydrolysis kinetic models, surface characterization analysis, and adsorption model. The results show that B-ACN exhibited a potent hydrogen inhibition efficiency of 97.36% at 4.50 g/L concentration, and maintained a hydrogen inhibition stability higher than 94.21% under temperature disturbance. In addition, theoretical calculations and surface characterization were performed to investigate the inhibition mechanism of B-ACN. SEM-EDS and XRD confirmed that the surface of the hydrolysis products of Al alloy dust in B-ACN solution is smooth and complete, with almost no generation of hydroxides. FTIR indicated that B-ACN adsorbs on the dust surface through the O atom. XPS and adsorption model suggested that the surface adsorption of B-ACN on the Al alloy dust involves both physical and chemical processes and follows the Langmuir adsorption model. Therefore, a dense and complete B-ACN protective film formed on the surface of Al alloy as a physical barrier, blocking the reaction between Al3+ and water molecules. This research provides a cost-effective, sustainable natural plant extract inhibitor to solve the risk of hydrogen generation and explosion, thereby achieving inherently safer industrial production and environmental protection.

Soil organic carbon enrichment in the particulate matter emitted by rural soils: A laboratory assessment

AbstractThe aim of this study was to assess the organic carbon (OC) content in the PM10 emitted by agricultural soils and rural roads under controlled conditions. Samples were collected from agricultural soils and rural roads. The PM10 was generated and collected using an electrostatic precipitator coupled with the Easy Dust Generator (EDG). This procedure ensures that the PM10 collected come specifically from soil. OC contents were measured in both the soil and PM10. The enrichment ratio (ER) was calculated as the ratio between OC content in the PM10 and OC content in the soil. The results showed that OC content in the PM10 ranged from 2.7% to 3.5% in agricultural soils and from 1.4% to 2.9% in rural roads. These values were comparable with the OC contents observed in fine particles transported by the wind, but lower than OC contents observed in PM10 samples collected in rural areas using active samplers and filters. A quadratic function described the association between OC in PM10 and OC in the soil. A negative potential function described the association between ERs and OC in the soil. Both associations suggested a saturation of OC in PM10 when the OC content in the soil was high. This information is crucial for a better comprehending of the dust emission role in the redistribution of OC within terrestrial ecosystems and to the atmosphere and oceans.

Development of handling energy factors for use of dustiness data in exposure assessment modelling.

Several exposure assessment models use dustiness as an input parameter for scaling or estimating exposure during powder handling. Use of different dustiness methods will result in considerable differences in the dustiness values as they are based on different emission generation principles. EN17199:2019 offers 4 different dustiness test methods considering different dust release scenarios (e.g. powder pouring, mixing and gentle agitation, and vibration). Conceptually, the dustiness value by a given method can be multiplied with a scenario-specific modifier, called a handling energy factor (Hi), that allows conversion of a dustiness value to a release constant. Therefore, a Hi, scaling the effective mechanical energy in the process to the energy supplied in the specific dustiness test, needs to be applied. To improve the accuracy in predictive exposure modelling, we derived experimental Hi to be used in exposure algorithms considering both the mass- and number-based dust release fraction determined by the EN17199-3 continuous drop (CD) and the EN17199-4 small rotating drum (SRD) test methods. Three materials were used to evaluate the relationship between dustiness and dust levels during pouring powder from different heights in a controlled environment. The results showed increasing scatter and difference between the Hi derived for the 2 test methods with increasing pouring height. Nearly all the Hi values obtained for both SRD and CD were <1 indicating that the dustiness tests involved more energy input than the simulated pouring activity and consequently de-agglomeration and dust generation were higher. This effect was most pronounced in CD method showing that SRD mechanistically resembles more closely the powder pouring.

The Sonopet iQ® Ultrasonic Bone Aspirator in Craniofacial Surgery: A Scoping Review and Qualitative Analysis

Background: The Sonopet iQ® Ultrasonic Aspirator is a surgical tool used for the fragmentation and emulsification of bone and soft tissue. Ultrasonic vibrations emulsify bone with cited benefits of decreased damage to surrounding soft tissue and minimal heat dispersion. Despite these potential benefits, there is a paucity of published articles on the safety and efficacy of the Sonopet® in the setting of craniofacial surgery. Methods: In accordance with PRISMA guidelines, MEDLINE and Pubmed were searched for articles that studied use of the Sonopet® for osteotomies in the craniofacial setting. Studies exclusively investigating soft tissue aspiration were excluded. Results: Out of 61 articles discovered, 22 met inclusion criteria and discussed a total of 816 patients. Of the 22 articles, there were 8 retrospective chart reviews, 7 case series, 5 cadaver models, and 2 case reports. Studies spanned multiple disciplines including otolaryngology, ophthalmology, craniofacial surgery, neurosurgery, and oral and maxillofacial surgery. Despite its frequent use in orthognathic and cranial vault remodeling surgery, only 4 studies described its use in these fields. The most commonly cited benefits of the Sonopet® were enhanced ergonomics and safety, discussed in 20 of the included studies. Eighteen studies claimed the Sonopet® was safer to use in surgically tight spaces compared to traditional drills. Four studies found decreased bone dust generation by the Sonopet® compared to conventional cutting devices. No studies reported an increase in postoperative complications due to the device. The most commonly cited disadvantage was the cost of the device, however, the majority of authors believed the benefits of the device outweighed the increase in cost. Conclusions: There is a dearth of research investigating the use of the Sonopet® in craniofacial surgery. Available studies emphasize the ergonomic and safety benefits of the Sonopet® and encourage expanded use of the device despite its cost.

First‐principles study on the surface properties and floatability of magnesite tailings and its main gangue

AbstractThe accumulation of magnesite tailings (MT) poses challenges such as resource wastage, land occupation, dust generation, and environmental pollution, thereby jeopardizing both physical and mental health. Urgent attention is required for the proper treatment of this solid waste material. An in‐depth investigation into enhancing the flotation processes of MT is essential. A comprehensive comprehension of the surface properties of MT and its principal gangue minerals assumes paramount importance in facilitating the desilication and decalcification of MT via flotation. In this investigation, a first‐principles study grounded in density functional theory was employed to scrutinize the surface properties, as well as the similarities and differences in flotability, of four minerals‐quartz, magnesite, dolomite, and calcite. The findings reveal that quartz's primary cleavage plane is (1 0 1), whereas that of magnesite, dolomite, and calcite is (1 0 4). The surfaces of magnesite, dolomite, and calcite exhibit chemical similarities, with Ca atoms demonstrating higher reactivity than Mg atoms. The hydrogen bonding between dodecylamine and quartz emerges as the most robust, while adsorption energies with the three carbonate minerals exhibit minimal disparity. The ongoing focus lies on the selection and optimization tests of decalcification reagents. A moderate quantity of dodecylamine manifests a certain desilication effect. However, excessive dosage compromises selectivity. The first‐principles approach offers guiding significance for elucidating the surface properties of MT and its primary vein minerals, along with investigating the adsorption mechanisms of flotation regents.

Measurement and analysis of airborne dust generation and dispersion from low-profile dump truck haulage in underground metalliferous mines

Exposure to harmful dust increases the risk of respiratory diseases among miners. This study employed high-resolution aerosol spectrometers to investigate the generation and dispersion of airborne dust resulting from operating low-profile dump trucks (LPDT) in a fully mechanised underground metalliferous mine (FMUMM). The aim is to measure and analyse the generation-transport-exposure dynamics of airborne dust from five different real-life scenarios due to the movement of loaded and empty LPDT in decline. The dust generation and dispersion profiles of various particle sizes, viz. ≤1 μm (PM1), ≤2.5 μm (PM2.5), ≤5 μm, ≤10 μm (PM10), and ≤20 μm, and occupational dust types which are vital for dust suppression and occupational health hazards were analysed. The study revealed that the proportions of ≤1 μm, ≤2.5 μm, ≤5 μm and ≤10 μm dusts were in the range of 0.4–3.2 %, 0.9–6.1 %, 3.7–16.9 % and 15.1–38.8 %, respectively. Loaded LPDT generated 77 % and 213 % greater TAD than the empty LPDT in homotropal and antitropal ventilation scenarios, respectively. The morphological analysis revealed that the dust particles are angular and irregular in shape. The mine dust exhibited hydrophilic nature. The wetting of the decline floor reduced the aerosolisation of 0.23–5.0, 5–10, 10–15, 15–20, and >20 μm size dusts in the decline by 57 %, 62 %, 62 %, 67 %, and 72 %, respectively. The regular wet suppression application efficacy increases with particle size in the decline. The study utilised Ventsim software to create and simulate 3D decline model, providing insights into the transport and distribution of airborne particles of different sizes. The field measurement and simulation result imply that respirable particles (≤10 μm) settle slowly in the decline, indicating that dilution is an effective strategy for controlling dust exposure in FMUMMs.

A Numerical Simulation of the Coal Dust Migration Law in Directional Air Drilling in a Broken Soft Coal Seam

Abundant industrial experiences have shown that directional air drilling technology is effective for gas drainage when drilling broken and soft coal seams. In this paper, the Eulerian–Eulerian model was used to simulate the gas–solid two-phase flow behavior of compressed air transporting coal dust in broken soft coal seams. The relationship between the degree of coal dust deposition, annular air pressure law, transportation of coal dust, aforementioned factors of rotational speed, particle size, and air volume could be determined. The results indicate that the particle size plays a significant role in the transport capacity of coal dust. Smaller particle sizes and a higher airflow result in a lower deposition degree of coal dust. When the particle size of coal dust is 1.69 mm and the airflow is 300 m3/h, in the case of coal dust generation at a rate of 0.24 m3/h, the deflection angle of the coal dust collection zone is increased by 130% as the rotational speed of the drill rod is increased from 0 to 120 rpm. Similarly, the deflection angle of the coal dust collection zone is increased by 12.8% in a 500 m3/h airflow under the same condition. Additionally, fine particle-sized coal dust is transported in a spiral line. The coal dust with larger particle sizes tends to be in the middle and lower parts of the hole and move along a specific trajectory. Industrial experiences of medium-air-pressure drilling confirm that a rotary drilling speed between 80 and 120 rpm, with a minimum air volume of 400 m3/h and preferably 500 m3/h, can promote a smooth hole drilling effect and enhance the construction safety in the gas drainage process.

Wear of the 3D Printed Polylactic Acid Elements Sliding against the Synthetic Resins at the Higher Speed Friction

Since the requirement of high dust-free levels, it is necessary to develop the technologies with anti-wear and low dust generation for drive elements that can be quickly printed. Polylactic acid and synthetic resins are often paired with each other for the 3D printed driven elements. To achieve "smooth friction", the adhesion wear under dry friction conditions should be reduced. To achieve a "high dust-free level", the anti-wear of the paired elements under higher speed friction should be improved to reduce the generation of abrasive dust. Therefore, wear of the 3D printed polylactic acid elements sliding against the synthetic resins at the high speed friction are investigated in this paper.

Study on the mechanism of polymer inhibiting purplish soil fugitive dust at macro–micro scale in Southwest China

Polymers with good adhesion properties are typically used as soil fugitive dust suppressants in infrastructure construction. This study investigates the dust suppression effect of hydroxypropyl guar gum (HPG), polyacrylamide (PAM), and starch (STA), as well as analyses their bonding mechanism on soil fugitive dust surface via laboratory experiments and molecular simulations. Laboratory test results indicate that the viscosity of HPG solution is the highest. At a mass concentration of 0.35 %, the maximum viscosity recorded is 288.5 mPa∙s, which is 44.8 and 264.08 mPa∙s higher than those of PAM and STA solutions, respectively. The wind-erosion resistance rate of soil fugitive dust samples treated with HPG is 98.63 %, which is 2.66 %, 3.51 %, and 30.43 % higher than those of PAM, STA, and water, respectively. The water-erosion rate of soil fugitive dust samples treated with HPG is only 2.06 %, which is 0.52 %, 1.05 %, and 12.11 % lower than those of PAM, STA, and water, respectively. HPG exhibits excellent cohesiveness and effectively inhibits the generation of soil fugitive dust. Molecular simulation results show that the adsorption energy of HPG is 4.8 %–48.3 % and 3.2 %–54.8 % lower than those of PAM and STA, respectively, thus indicating the higher adsorption capacity of HPG. The distribution of HPG on the surface of soil fugitive dust components is the most concentrated. The self-diffusion coefficient of HPG is 0.3–6.7 and 1.2–12.4 times lower than those of PAM and STA, respectively; therefore, the structures of the HPG/soil fugitive dust component simulation systems are more stable. The radial distribution function shows that the van der Waals force is the primary force affecting the molecular dynamics behaviour, which signifies physical adsorption. The binding mechanism of polymers on the surface of soil fugitive dust is that the polymer approaches the surface of soil fugitive dust through van der Waals forces and eventually adsorbs onto the surface of soil fugitive dust to bond with it. This study provides a theoretical foundation for the development of more effective soil fugitive dust suppressants for infrastructure construction.

Study on the influence of cross-section shape on the characteristics of wind flow field in heavy-daty railway tunnel

In order to reduce the coal dust pollution when the heavy train enters the tunnel and to ensure the safety of railroad operation, this paper adopts numerical simulation to study the characteristics of the wind flow field of the heavy train passing through different shapes of tunnels. The results show that the shape of the tunnel section has a significant effect on the piston wind characteristics of the train entering the tunnel. When the train passes through the tunnel, the value of the wind pressure and the gradient of the pressure on the surface of the carriages increase from horseshoe shape, high wall shape and high arch shape. The vortex structure generated at the entrance of the horseshoe tunnel is the smallest and the flow field is more stable, and the wind turbulence shows significant weakening effect; when the rear end of the car enters the tunnel, the range of the influence of the piston winds outside the tunnel is in order of smallest to largest for the horseshoe, high wall, and high arch tunnels; in the wake region, the central region of the strong vorticity zone in the horseshoe tunnel is more continuous, reducing the instability of the airflow in the tunnel. The results of this study are of great significance in understanding the characteristics of the wind flow field and the effect on dust generation when heavy trains pass through the tunnel.

Elemental (CNS) and isotopic (δ13C and δ15N) characterization of local sources to atmospheric dust at Trombay, Mumbai, using elemental analyzer–isotope ratio mass spectrometry

Particulate matter (PM) in the air has significant implications for human health and the environment, particularly in urban areas with high concentrations. This study focuses on the isotopic (δ13C and δ15N), elemental (CNS) as well as the total carbon to total nitrogen ratio (TC/TN) characterization of PM in Trombay, Mumbai. Monthly atmospheric dust samples were collected from 2016 to 2020 during the premonsoon and postmonsoon seasons. The average elemental concentrations for premonsoon samples were N (1.73% ± 0.25%), C (7.38% ± 0.72%), S (0.84% ± 0.13%), and TC/TN ratio (4.38 ± 0.86). For postmonsoon samples, the average elemental concentrations were N (1.47% ± 0.185%), C (6.95% ± 1.04%), S (0.84% ± 0.13%), and TC/TN ratio (4.80 ± 0.94). The average δ13C values for premonsoon and postmonsoon seasons were −24.31 ± 1.15‰ and −24.56 ± 1.20‰, respectively. The average δ15N values for premonsoon and postmonsoon seasons were 5.22 ± 1.92‰ and 4.57 ± 1.32‰, respectively. The results showed variations in elemental concentrations between the seasons, with higher values observed in premonsoon samples which can be attributed to increased dust generation from land and sea. Overall, this study provides insights into the local sources and characteristics of PM in the Trombay area and highlights the importance of long-term monitoring to understand the seasonal variations in PM composition.

PREVENTION OF THE SPREAD OF DUST FROM POLYMETALLIC WASTES WITH A DOUBLE-BARRIER DUST PROTECTION SYSTEM

Waste from the metallurgical industry contains many harmful impurities. If improperly handled and stored in open landfills, small particles of this waste can be picked up by the wind, carried over long distances and harm human health and pollute the environment. Lead production waste is especially dangerous. Such objects must be handled well, and various dust protection systems must be used to prevent the spread of dust. It is not a trivial task in the case of large sizes of such objects. The lead waste pile formed by the polymetallic plant near the city of Shymkent, Republic of Kazakhstan, is a huge conical mountain with a base diameter of 240 m and a height of more than a 20-story skyscraper. This pile is not managed at all. The pile produces a large amount of lead waste dust, which is carried by the wind to the city and surrounding areas. A numerical study of the wind flow around a hazardous pile was carried out. The dust generation area for an unprotected pile reaches 6,318.68 m&lt;sup&gt;2&lt;/sup&gt;. This dust generation area affects human health and pollutes the environment near the pile. The barrier dust protection system can significantly reduce the power of harmful dust formation. For the first time, analysis and optimization of a dust protection system consisting of two concentric barriers, where heights are significantly less than the height of the object the system handles, was carried out. The results of the research show that installing this fairly simple system around the lead waste pile reduces the formation of air pollutants by 538 times or 99.81&amp;#37; compared to an unprotected object. In addition, the remaining dust particles that can be picked up by the airflow rise to a height of &amp;#62; 140 m above the Earth's surface when using such a protection system and therefore do not affect human health.

Characteristics of Suspended Road Dust According to Vehicle Driving Patterns in an Urban Area and PM10 Content in Silt

Characterizing the influence factors of exhaust gas based on the suspended road dust on paved roads, according to the number of vehicles and their distance with regard to driving pattern, is important in order to provide a coefficient for driving patterns to find a model equation. This has been a limitation of previous studies, in which this was difficult to carry out in a large area reflecting various driving patterns because some sections were selected according to empirical measurement results, and only one vehicle measurement was used to find the level of road dust. This study measured the concentration of suspended road dust that could occur, depending on the vehicle’s driving patterns, on an experimental road in Yongin, South Korea, from May to July 2023. The study was conducted to determine the degree of the effect of exhaust gas, according to the concentration of suspended road dust generated, by determining the separation distance based on real-time measurements. This study attempted to determine the changes in suspended road dust based on driving patterns in urban areas and factor in the concentration of suspended road dust with regard to emission characteristics in terms of exhaust gas and particulate matter with a diameter of 10 microns or less (PM10). This was in accordance with conditions evaluated using mobile laboratories, based on suspended-PM10-concentration-measuring equipment. This study mainly focused on the following main topics: (1) increasing the level of suspended particulate matter at less than 10 m intervals produced by exhaust gas; (2) decreasing the level of suspended road dust with an increase in the number of vehicles, with the area measured at a distance of three cars in front showing the lowest level of suspended road dust in the air and a low level for the rear vehicle; (3) demonstrating that PM10 is effective in measuring the generation of suspended road dust; and (4) evaluating suspended road dust levels by road section. Based on the results, this research is necessary to more appropriately set the focus of analyses that aim to characterize suspended road dust according to exhaust gas and PM10 content in silt.

TRANSPORT SUPPORT OF METALLURGICAL PRODUCTION WASTE RECYCLING

Purpose. One of the possible ways to improve the efficiency and environmental friendliness of metallurgy is processing and reuse in production as raw material of iron-containing dusty waste. At the same time, an integral component of such waste recycling is the transportation of iron-containing dust from the sources to the granulation areas, where it is processed. However, existing technological solutions for dust transportation are characterized by significant dust generation both during loading-unloading operations and during transportation. In this regard, the paper considers dust-free transportation technology for dusty waste using tank containers. Methodology. During the research, methods of geospatial analysis of transportation routes, taking into account dimensional and weight restrictions, methods of planning the operation of motor vehicles on routes, methods of the theory of shunting work on railway transport were used. Results. The work on the application of one of the metallurgical enterprises presents the methodology for determining the required fleet of vehicles and the main technical and technological parameters of schemes for the iron-containing dust transportation in tank containers by road and rail transport. Scientific novelty. The obtained research results on transport process parameters allow to perform scientific and economic justification of choosing a technological scheme for the transportation of dust waste. Practical significance. The presented technological schemes can be used as solutions for the transportation support of recycling iron-containing dusty waste in metallurgical production.

Fugitive Dust Associated with Scrap Metal Processing

Fugitive dust (FD) is a nuisance and potential health issue, particularly in environmental justice communities that can experience high levels of contaminated FD. This community-initiated study examined FD from a scrap metal processor in Detroit, Michigan, to determine whether the FD was contaminated, how it migrated through the community, whether wipe or composite road dust samples were preferable, and whether literature profiles adequately characterized this source. The study was motivated by community concerns, as well as a massive subsidence/upheaval event resulting from excessive accumulation of mill scale, which is a type of scrap metal, at the facility. We collected 57 wipe samples from windows and other surfaces, and 20 composite road dust and surface soil samples, which were analyzed by X-ray fluorescence. Concentrations were expressed using the fraction of the reconstructed mass. We also compared results to air quality monitoring data and calculated pollution indices and enrichment factors. Samples collected near the processor had high levels of Cr, Cu, Fe, Ni, Sr, and Zn compared with background soils, and levels remained elevated in residential areas several blocks distant. Composite road dust/sediment samples appeared preferable to wipe samples for chemical characterization. The available chemical profiles did not match the FD composition, suggesting the need for local profiles. The high level of Fe, which is consistent with mill scale, was a novel finding and caused the road dust to exceed health protection screening levels. Numerous metal scrap facilities operate locally and nationally, and our results show the need to improve controls to limit or eliminate FD emissions from industrial sources using enforced policies that reduce dust generation and truck track-out.

Effect of spatial and temporal “drought legacy” on dust sources in adjacent ecoregions

AbstractDrought affects the occurrence and intensity of aeolian dust events in many ecoregions. This study investigated the effects of “drought legacy” (the cumulative temporal persistence of drought's consequences on the earth system) on dust generation, a topic which had not previously been evaluated. We investigated the potential dust/drought legacy relationship in the USA's Southern Great Plains and Chihuahuan Desert ecoregions over 14 years, including the 2011–2012 extreme drought, at spatial distances up to 100 km around dust point sources and for up to 5 years' drought history. At every temporal and spatial scale, drought levels associated with dust initiation points in the two ecoregions were significantly different. Chihuahuan Desert dust sources concentrated in areas of severe to extreme drought, while those in the Southern Great Plains, which experiences greater land use, spanned wider ranges of drought conditions. At short temporal scales of drought (1 week and 1 year), dust initiation in the Chihuahuan Desert was associated strongly with severe to exceptional drought conditions at all spatial extents, while Southern Great Plains dust sources were linked to lower drought intensities. For longer drought histories (the past 2 and 5 years), Chihuahuan Desert dust sources were connected with moderate to severe drought, while Southern Great Plains dust sources were linked to moderate drought, at all spatial extents. Drought's legacies, extending over multiple years and kilometer scales, are shown to have roles in subsequent dust events at regional scales, though they can be regionally modulated by land use practices and ecosystem characteristics.

Evolutionary mechanism and particle characterization analysis of dust produced by wet-mix shotcrete in tunnels

Wet-mix shotcrete, an essential form of concrete support, has been widely applied in underground constructions such as tunnels and mines. This study analyzed the gas jet structure and particle velocity differential equations in the wet-mix shotcrete process and physicochemically characterized collected dust samples. Based on field measurements and laboratory analyses, we established an experimental platform and a numerical simulation model for wet-mix shotcrete to investigate dust generation characteristics. The results showed the following: 1) The particles generated during wet-mix shotcrete primarily consisted of cement particles, exhibiting a spherical and blocky shape with a relatively regular morphology. However, their surfaces possessed numerous burrs and pores, resulting in poor wettability. 2) Suspended aerosol particles mainly comprised particles below 10 µm, exhibiting a unimodal particle size distribution. Smaller particles showed a higher abundance, with particles below 2 µm accounting for over 95% of the total particles. 3) The dust generation during wet-mix shotcrete was significantly influenced by the compressed gas flow rate and material viscosity. An increase in the gas flow rate or material viscosity led to higher production of fine particles. This study elaborated the mechanisms underlying particle generation during wet-mix shotcrete, providing valuable insights for wet-mix shotcrete dust control techniques.

Characterization of 10 nm – 10 μm coal dust particles generated by simulated different cutting and drilling parameters: mass concentration distribution, number concentration distribution, and fractal dimension

Nano-to-micron-sized coal dust can cause coal workers’ pneumoconiosis (CWP), and cutting and drilling are the main coal dust-generating processes. Based on a self-developed simulated coal cutting and drilling dust generation system, the effects of cutting parameters (tooth tip cone angle, impact angle, roller rotary speed, cutting speed) and drilling parameters (drill bit diameter, drilling speed) on the mass concentration distribution, number concentration distribution and fractal dimension of 10 nm – 10 μm coal dust were investigated. Results show that the mass concentration of 10 nm – 10 μm coal dust generated by cutting/drilling peak at 5.7 – 7.2 μm, while the number concentrations during cutting and drilling respectively peak at 60 – 90 nm and 20 – 30 nm. During both cutting and drilling processes, the generated coal dust particles in 10 – 300 nm account for > 90% of the total 10 nm – 10 μm coal particles, while PM2.5 in PM10 is generally below 18%. It is also found that smaller tooth tip cone angle, larger impact angle, lower roller rotary speed, smaller drill bit diameter, or lower drilling speed can reduce the generation of 10 nm – 10 μm coal dust with a fractal dimension of 0.94 – 1.92. This study reveals the distribution characteristics of nano- to micron-sized coal dust particles under different cutting and drilling parameters, and the research results can serve as reference for adjusting cutting and drilling parameters to lower down the 10 nm – 10 μm coal dust generation and thus prevent the CWP.

Analysis of the Functions of Cosmology Dust in Galaxy Formation

The physical laws related to star formation in galaxies are the key to understanding the formation and evolution of galaxies. The dust in the interstellar medium has a significant effect on both the star formation and the observational properties of the galaxy. Understanding the properties, effects, and evolution of cosmology dust in galaxies is an essential part of a complete picture of galaxy formation and evolution. In this study, the background of interstellar dust research in galaxy formation will be summarized. Some basic concepts and physical properties of galaxies are introduced. The definition, classification and evolution of galaxies will be discussed. It then states the properties of cosmology dust in galaxies, including the basic concepts of physics, properties, generation, and evolution of dust. It will then focus on the role of interstellar dust in galaxies, including its basic concepts and background. These results shed light on guiding better understanding of the functions of cosmology dust in galaxy formation.

Development and experimental study of a scaled model for dust dispersion in fully-mechanized mining face

Model experiment is one of the research methods for the fundamental theory of coal mine dust control. To address the current deficiencies in experiment development for research on dust migration rules, a scaled model for dust dispersion in a fully-mechanized mining face was constructed based on the design prototype of the 25211 mining face at the Hongliulin mine, using a similar theory. The model includes a mining face, a return airway, a haulage roadway, and a subsidiary roadway constructed using aluminum alloy profiles and tempered glass. The model uses U-shaped exhaust ventilation. The shearer, hydraulic support, and reverse loader are equipped with dust sources, and each dust source operates independently with distinct dust generation processes that do not interfere with each other. An experimental plan for dust diffusion during shearer dust generation was designed with a wind speed of 1.0 m/s. Preliminary model experiment was conducted based on this model. The results showed that the farther away from the dust source, the lower the dust concentration. The relative mass distribution and cumulative mass distribution of falling dust particles also showed that the farther away from the dust source, the smaller the particle size of the falling dust particles. The maximum size distribution decreased from 51.4 μm to 27.9 μm, and the average particle size decreased from 34.9 μm to 20.6 μm. The test model results were validated by field tests, indicating that the constructed model has good reliability. Finally, the critical areas for future research based on this model were proposed. The development of the model provides valuable experimental support for the theory of multi-source dust transportation in the airflow on the fully-mechanized mining face.