Abrasive Dust Research Articles

Effect of “black carbon” on antimony accumulation in traffic-loaded topsoil

Traffic-loaded areas have been of increasing concern due to the potential risk of carcinogenic pollutants, including antimony (Sb), which accumulates mostly in atmospheric particles (PM) and can interact with soil organic matter (Corg). The stability of Sb in topsoils was studied via the adsorption mechanism using standard soils and Corg-reach vehicle-produced particles as the unique source of “traffic” Sb. The mixed adsorbents were prepared from loamy sand and clay standard soils, and braking abrasion dust and diesel engine soot as Sb sources in atmospheric PM. Whereas the black carbon (BC), as part of Corg, disposes of exceptional adsorption properties compared to the other Corg, all adsorption experiments were performed identically on the adsorbents prepared from the original standard soils and Sb source materials and on the adsorbents prepared from the same materials annealed at 375 °C to ensure only BC participation in adsorption processes. The concentration of the Sb model solution corresponded to the average Sb content in rainwater from traffic-loaded localities. In addition to Sb, the Corg and iron (Fe) were monitored. The sorbability of Sb on the loamy sand soil mixtures increased up to 90% compared with the pure soil due to new active surface sites for Sb binding created due to the Corg added with the source material. The clay soil mixture containing 10 times more Corg compared with the loamy sand soil accumulated the Corg from the source material, which resulted in blocking active sites and a decline in Sb sorbability by up to 20%. The processes performed identically with original and annealed materials showed the same trends and confirmed the key role of BC and soil quality in the accumulation and stability of Sb in traffic-loaded topsoils. The participation of Fe in Sb surface interactions was not observed.

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.

Arc Fault Protection of the High-Current Busbar Assembly of an Ore Furnace

The design features of high-power ore furnaces are the transformer’s secondary winding made of 4–8 isolated splits and a busbar assembly made of the same number of paired bifilar bus tubes, spaced 20–40 mm apart. Only an arc fault (AF) can occur between paired bus tubes in such an assembly, during which the assembly with currents of 35–150 kA can be completely destructed. To protect against AFs, these bus tubes are wrapped in several layers of gluey fiberglass cloth. However, such cloth is abraded under the impact of airborne abrasive dust particles during furnace operation, and coal dust in the air creates the conditions for an AF. A new current protection with a magnetic current transformer (MCT), which prevents busbar assembly destruction, is suggested. Its design is based on the analysis of the distribution of busbar assembly magnetic fields. The choice of MCT position is justified, and parameters of its windings are determined; MCT construction and fastening are described, and a technique for reliable MCT output signal transmission under strong magnetic fields and with a specified protection threshold is suggested. These protections are currently the simplest and cheapest tool for preventing the complete destruction of an expensive busbar assembly in events of AFs during it.

Non-exhaust particulate pollution in Asian countries: A comprehensive review of sources, composition, and health effects

Recent regulations on exhaust emissions have led to an increase in non-exhaust emissions, which now surpasses exhaust emissions. Non-exhaust emissions are mainly generated from brake and tire particle abrasion, road wear, and re-suspended road dust. In Asia, non-exhaust emissions have increased significantly over the past 50 years, resulting in almost 92% of the population breathing polluted air, which accounts for 70% of air pollution related-deaths. Most Asian countries with poor air quality are developing or underdeveloped. Taking this into consideration, the current study aims to shed light on particulate pollution from non-exhaust emissions in the Asian context to assess the current status and its health consequences and provides technological solutions. The study is based on an in-depth analysis of existing reviews and research concerning non-exhaust emissions and their health impacts in Asia to pinpoint knowledge gaps. The study found that particulate pollutants had exceeded WHO's standards in many Asian countries, bringing deleterious health consequences among children and the elderly. The findings underscore the significance of future researchers' efforts to devise solutions that curtail non-exhaust emissions, ultimately reducing air pollution, augmenting air quality, fostering better health outcomes, and paving way for a more sustainable future before it is too late.

Research on polishing aluminum alloy optical elements with a new solid flexible bonnet tool

As a common optical element material, aluminum alloy has been widely used because of its high reflectivity, easy lightweight design and other advantages. However, due to the soft texture and large plasticity of aluminum alloy, the surface is prone to mechanical damage during processing. In order to improve the surface quality and processing efficiency, this paper designs a new type of solid flexible bonnet tool to polish aluminum alloy optical elements. Then the finite element analysis method is used to compare the performance of several bonnet tools. Finally, the aluminum alloy polishing experiment is carried out, and the material removal mechanism and the factors affecting the polishing surface quality are analysed. The results show that the new solid flexible bonnet tool has good deformation stability, good fit with the workpiece, and can achieve high efficiency and precision polishing of aluminum alloy optical elements. According to the pressure distribution in the contact area, the abrasive particles in the sliding state are divided into three removal modes: micro-cutting, micro-plowing and micro-rubbing. At the same time, the hard particles in aluminum alloy have an important influence on the surface morphology after polishing. Due to the strong plasticity and viscosity of aluminum alloy, the abrasive dust is easy to adhere to the surface of the workpiece, reducing the surface roughness.

44 Dual Proteomic Exploration of the Mechanisms Underlying Brake Dust-Induced Impairment of Phagocytic Capacity in Macrophages

Abstract Exposure to brake abrasion dust (BAD) reduces the phagocytic capacity of macrophages, possibly contributing to increased risk of airway infections in polluted regions. The mechanisms that underlie this toxicity remain to be characterised and, considering that pre-exposure of respiratory bacteria to alternative traffic-related particulates enhances their dissemination into the lungs of mice, may include changes in the virulence of pathogens themselves. Dual proteomic screening (TMT-labelled UPLC-MS) was performed for RAW 264.7 monocyte-derived macrophages and S.aureus (USA300) following 24h exposures to BAD (0-16 ug/ml). In S.aureus, expression of agr-regulated, anti-leukocytic virulence factors (lipases, staphopains, hemolysins) increased in a dose-dependent manner as well as proteins required for epithelial invasion (serine proteases) and antibiotic resistance. RAW 264.7 exhibited a predominantly adaptive response following exposures, enhancing expression of proteins required for metal homeostasis, NFkB-mediated inflammation and endosomal maturation. However, disrupted expression of proteins required for electron transport chain activity and Fe-S cluster synthesis accompanied significant dose-dependent reductions in ATP production (60-82%, p< 0.001) while transition electron microscopy (TEM) detected disrupted mitochondrial membrane morphology. TEM also identified reductions in pseudopodia length in exposed macrophages (54% shorter than control, p< 0.05), highlighting a mechanism by which BAD exposure may decrease the incidence of host-pathogen interactions. These data highlight dual mechanisms by which BAD emissions could impair bacterial phagocytosis and enhance susceptibility to airway infections. Through avoidance and suppression of host anti-microbial mechanisms by the bacteria and, as actin polymerisation depends on ATP availability, loss of mitochondrial function and downstream pseudopodia projection in macrophages.

Analysis of Electric Transmission Failure Induced by Electrostatic Migration and Deposition of Abrasive Dusts in SADA

The electric transmission failure induced by the electrostatic migration and deposition of the friction-pair-produced abrasive dusts in the Solar Array Drive Assembly (SADA) is studied for the first time by integrating experiments and Finite Element Method (FEM) simulation. Particle morphology and composition are characterized by SEM and X-ray EDS, respectively. The size, distribution and average charge of the abrasive dusts are characterized by PSDA as well as the home-made particle charge measurement device. The results show that the dusts’ sizes are in the range of 10–40 μm, and the dusts are primarily composed of Ag and a small amount of Cu and S. Sliced abrasive dusts with an average diameter of 30 μm and a charge of 85 e are used for the FEM prediction of particle trajectory, which is consistent with the theoretical calculation results. The electromagnetic field distribution in the SADA and the electrostatic migration and deposition of abrasive dusts are predicted and analyzed by adopting the FEM method. The experimentally observed dusts’ trajectories in a vacuum chamber with 0.02 Pa vacuum degree are consistent with the simulation results, which qualitatively verifies the accuracy of the FEM model. The predicted results show that the irradiation-induced conductivity increase in polyimide material has little influence on the electric field distribution and the migration and deposition of the abrasive dusts but has great influence on the local current density. Both the potential differences between the two adjacent conducting rings and the loose contact between the electric brush and the conducting rings have significant influence on the migration and deposition of the abrasive dusts, which may greatly increase the surface discharge risk and the electrical transmission instability in the SADA. This study is conducive to the safe and stable operation of the on-orbit spacecrafts.

PREPARATION FOR THE DISPOSAL OF SLUDGE FROM THE INDUSTRIAL WASTEWATER TREATMENT PLANTS

Due to the lack of local facilities for recycling, neutralization and treatment of wastewater at many metallurgical enterprises the wastewater is mixed; surface wastewater, blowdown of recycled water supply cycles, chemically polluted wastewater, spent cooling and washing liquids. As a result of the joint processing of the mentioned waste waters in sewage treatment plants, the specific sediments containing compounds of heavy metals and toxic substances are formed. The data on metal content in a solid phase of mixed sediments of different metallurgical enterprises is presented. It is noted that toxicity of sediments can be reduced by excluding the discharge of used concentrated solutions into the sewerage system, by regeneration of used technological and detergent solutions at the place of their formation. The scheme of sludge processing, which provides for their flocculation, gravitational thickening and mechanical dewatering, is proposed. It is shown, that the most efficient flocculant for treatment of sludge of mixed composition is a high-molecular-weight anionic flocculant with the content of ionogenic groups up to 10 %. The effective dosage is 5‒7 kg/t dry solids of sludge. For mechanical dewatering of flocculated sludge, chamber, membrane and belt filter presses as well as screw centrifuges (decanters) can be applied. Depending on the metal content, the dewatered sludge can be used for technical remediation of disturbed areas or for processing in the cement industry. Present study shows a schematic diagram for the preparation of mixed sewage sludge and dry industrial wastes of a metallurgical plant for technical remediation of disturbed lands. For processing sludge with water content between 65‒75 % in cement industry it is recommended to mix the mechanically dewatered sludge with dry wastes, such as abrasive dust and grinding powders, waste core mixtures for casting and other similar wastes.

Efficiency of dusted gas cleaning using a slotted filter

The cleaning of industrial gases from dust is one of the most significant current environmental protection problems. The search for new, more advanced and effective ways to clean dust gases and dust collector designs is based on the diversity of technological conditions for dust formation, the physicochemical properties of gases and trapped particles, and an increase in technical and economic requirements for cleaning processes. When cleaning hot or chemically aggressive gases and capturing abrasive dust, the use of electrostatic precipitators, bag, fibrous and granular filters is often associated with difficulties in protecting the devices from harmful factors or ensuring sufficient cleaning efficiency. The design features of slotted filters permit their use in solving such problems. An engineering method for calculating slotted filters developed on the basis of theoretical ideas and experimental studies is used to model and design slotted filters with specified performance indicators to ensure high cleaning efficiency and low hydraulic resistance. This technique is based on theoretical patterns of filtration using basic dust particle deposition mechanisms on isolated cylinders in relation to the stationary stage of the filtration process. A computer program that simulates the process of cleaning dusty gases in slotted filters has been developed. This makes it possible to determine the optimal operating parameters, design dimensions and regeneration conditions of slotted filters based on a specified cleaning efficiency and hydraulic resistance, taking into account the properties of dust and gas during prolonged continuous operation of the filter.

Gas Dedusting by Slotted Filter

A new deduster is proposed, in which a slotted filter screen with perforated frame wire wound in several layers is used to collect dust, with specific sizes of slots between the coils and layers of wire. The filter is equipped with an efficient regeneration system and can be used to clean hot, aggressive gases, as well as abrasive dust. A stationary filtration method on various dusts with high (98–99% or more) or target cleaning efficiency and acceptable wall friction is developed and studied. The calculation method, which enables cleaning simulations and determination of optimal performance parameters and dimensions of the slotted filter structure, is presented.

Frictional wear characteristics of nickel-based alloy and reactor material in pressure vessel reactor

Abstract The reactor pressure vessel was contact sealed with a double-channel O-ring made of Inconel 718 alloy and nuclear power material SA508. The fretting wear characteristics of Inconel 718 O-tube and SA508 plate friction pair were tested by fretting wear testing machine to explore the failure mechanism of reactor pressure vessel seal system. The test conditions are as follows: normal temperature, normal loads of 10, 20, and 40 N, displacement amplitude of 600 μm, the number of cycles of 10,000, and frequency of 4 Hz. Results show that the coefficient of friction (COF) increased with increasing normal force. Significant material losses were detected during the relative sliding of the contact surface of SA508. A large number of abrasive dust accumulated at the edge of the contact zone, forming a large number of oxides. During the friction of Inconel 718 O-ring, plastic deformation occurred, and a plastic flow layer was formed. The plastic deformation flow at the contact point formed an adhesive connection point, producing adhesive wear and oxidative wear. The wear mechanism was characterized by the combination of oxidative wear and abrasive wear.

Impact of Thermal Stress on Abrasive Dust from a Carbon Fiber-Reinforced Concrete Composite

Recently, a novel corrosion-resistant construction material, Carbon Concrete Composite (C3), consisting of coated carbon fibers embedded in a concrete matrix, was introduced. However, thermal exposure during domestic fires may impact the release of organic pollutants and fibers during abrasive processing and/or demolition. Consequently, the objective of this study was to explore the emission characteristics of toxic compounds and harmful fibers during the dry-cutting after exposure to 25–600 °C (3 h, air). These parameters mimic the abrasive machining and dismantling after a domestic fire event. Mass spectrometry and chromatography served as analytical methodologies, and no organic pollutants for exposure temperatures ≥ 400 °C were found. In contrast, significant amounts of pyrolysis products from the organic fiber coating were released at lower temperatures. Studying the morphology of the released fibers by electron microscopy revealed a decrease in fiber diameter for temperatures exceeding 450 °C. At ≥550 °C, harmful fibers, according to the World Health Organization (WHO) definition, occurred (28–41 × 103 WHO fibers/m3 at 550–600 °C). This leads to the conclusion that there is a demand for restraining and protection measures, such as the use of wet cutting processes, suction devices, particle filtering masks and protective clothing, to handle thermally stressed C3.

Effects of abrasive dust and metal exposure among dental technicians

Effects of abrasive dust and metal exposure among dental technicians

Safety considerations for SPIcDER: Spacesuit integrated carbon nanotube dust ejection/removal system

This paper presents a multi-tier safe implementation of the Spacesuit Integrated Carbon Nanotube Dust Ejection/Removal (SPIcDER) system. SPIcDER mitigates dust contamination of spacesuits and flexible surfaces during surface exploration of Moon and Mars. SPIcDER has Carbon nanotube (CNT) fibers embedded within the spacesuit outerlayer. These are energized using high voltage, low power, Alternating Current (AC) signals (∼350–1000 V). Laboratory experiments show the time-varying electric fields produced by SPIcDER repel the dust.This system mitigates astronaut exposures to lunar dust, and protects spacesuits and flexible surfaces from dust abrasion, wear and tear, and reduction in thermal performance. The adherence of lunar dust, and its entry into the habitable volume of habitats/landers, which was a major problem during Apollo missions, is also minimized.In this study, we review the primary health and safety aspects of SPIcDER for astronauts operating in these spacesuits. Simulation using ANSYS Maxwell® and preliminary experimental investigations were performed to conduct safety analysis and provide recommendations for implementation of SPIcDER for lunar mission operations.

Modelling and estimation of Wide Wheel abrasion values of building stones by multivariate regression and artificial neural network analyses

The Wide Wheel is a recent abrasion test method (WA) proposed for building stones. The WA test is carried out by special equipment using abrasive dust on prismatic building stone samples. The purpose of this study is providing a methodology for practical estimation of the WA values from dry unit weight (γ), open porosity (PO), P-wave velocity (VP) and uniaxial compressive strength (UCS) values. In the study, test data from previous studies were compiled. Multivariate regression analyses (MLR), Feed Forward Back Propagated (FFBP) and Generalized Regression Neural Networks (GRNN) algorithms of Artificial Neural Networks (ANNs) were employed in the analyses. Equations by MLR analyses to estimate the WA values for 5 models were proposed. Then, FFBP and GRNN analyses were performed, and their prediction performance results were assessed. All five models were determined to be strong enough to be used in practice, although FFBP and GRNN are found to be stronger in prediction capability than the MLR method.

Experimental investigation of µ-abrasive jet machining with dust collection mechanism

Micro abrasive jet machining process is an advanced machining process used for the production of micro holes, micro channels and machining of different type of brittle materials. It is a non contact type machining process, were highly pressurized air and abrasive particles are mixed using a mixing chamber and directed towards the work piece. The material is removed by means of mechanical erosion. During the machining time, there are lot of abrasive particles expelled out and it may cause environmental pollution. To avoid this problem an abrasive dust collector mechanism with liquid film is used in the current work. In this experiment the work piece is placed in the liquid chamber and three input process parameters such as mass flow rate, standoff distance, motor speed and there effects on the output responses such as material removal rate, radial overcut and area of frosted zone is discussed. The process parameters are optimized using Taguchi method and utility concept in Minitab statistical software.

EDEM Investigation and Experimental Evaluation of Abrasive Wear Resistance Performance of Bionic Micro-Thorn and Convex Hull Geometrically Coupled Structured Surface

Procambarus clarkii was found to have excellent anti-wear performance against abrasive materials. To improve the wear resistance performance of the soil-engaging component of agricultural machinery, in this study, the micro-thorn and convex hull coupled geometrical structured surfaces inspired from the cephalothorax exoskeleton of the Procambarus clarkii was selected as the bionic prototype. By adopting bionic engineering techniques, three types of novel geometrical structured surfaces were proposed, which were bionic single, double and triple micro-thorn coupled convex hull surfaces (Bionic Type 2, 3 and 4, respectively). The anti-abrasive wear properties of these proposed geometrical surfaces were compared with a conventional bionic convex hull structured surface (Bionic Type 1) and a surface without any structures (smooth). Abrasive wear tests were conducted by using a rotational abrasive wear testing system. The accumulative test time was 80 h and the total wear distance was 6.09 × 105 m. By adopting the EDEM software (discrete element modeling), the Archard Wear model was selected to simulate the wear behavior of five different surfaces. In addition, the wear mechanisms of different surfaces were investigated. The results showed that the smooth surface suffered the most severe abrasive were, the abrasion loss reached 194.1 mg. The anti-abrasive properties of bionic geometric structured non-smooth surfaces were greatly improved; the reduction in terms of abrasion losses ranged between 20.4% and 94.1%, as compared with the smooth surface. The wear resistance property of micro-thorn and convex hull coupled structured surfaces were greatly improved as compared with convex hull and smooth surface. Bionic Type 3 was found to have the best anti-abrasive wear property: the abrasion loss was 11.5 mg. The wear morphology was observed by a scanning electron microscope. Smooth surface was characterized with wide, large size of grinding debris, while the bionic non-smooth surface featured narrow and small size abrasive dust. The results obtained from EDEM simulation agreed well with those of the aforementioned real scenario tests. It was revealed that the wear areas of the micro-thorn and convex hull coupled structured surface were mainly concentrated on the edge of convex hull and micro-thorn that faced the coming direction of particle flow. The geometric structure of the convex hull had beneficial effects on changing the movement behavior of particles, which means the stream of particle flow could be altered from a sliding to rolling state. Consequently, the ploughing and cutting phenomena of particles that act on the surfaces were greatly mitigated. Moreover, after being coupled with micro-thorns, the anti-abrasive wear preparty of the bionic convex hull geometrical structured surface was further improved. The rebound angle of particle flow that contacted the bionic micro-thorn coupled convex hull structured surface was greater than that of the conventional convex hull surface. Therefore, the dispersion effect of particle flow was further enhanced, since the movement behavior of the subsequent impact particle flow was altered. As a result, the wear of the bionic non-smooth surface was further reduced. This biconically inspired novel micro-thorn and convex hull coupled structured surface could provide theatrical and technical references to enhance the wear resistance performance of the soil-engaging component of agricultural machinery and mitigate the problem of abrasive wear failure.

Investigation of Chemical Composition and Fiber-Occurrence in Inhalable Particulate Matter Obtained from Dry Cutting Processes of Carbon Fiber Reinforced Concrete Composite, Concrete and the Carbon Fiber Reinforcement Materials

The most commonly used construction material nowadays is steel-reinforced concrete which underlies corrosion and thus buildings are susceptible for structural collapses. Recently, a new construction material resistant to oxidation and with a higher tensile strength called carbon concrete composite (C3) was developed. The new material allows resource-saving constructions using carbon fiber instead of steel reinforcement materials embedded in a concrete matrix. C3 reinforcements consist of carbon fibers coated with an organic polymer matrix. In this study, abrasive dust from a dry cutting process of two C3 reinforcement materials, as well as a C3 material were investigated with respect to the occurrence of toxic fibers or harmful organic compounds in the inhalable particulate matter (PM) fractions PM2.5 and PM10. It could be shown that the ratio between elemental and organic carbon in PM10 is dependent on the shape of the C3 reinforcement material due to different mechanisms of PM formation. This could have an impact on the toxicity of different C3 reinforcement materials. Harmful fibers according to the World Health Organization (WHO) definition like they are found in asbestos concrete were not found. However, bisphenol A (BPA) as well as the PAHs phenanthrene, anthracene, fluoranthene and pyrene were found due to pyrolysis of the organic matrix material at the edge of the sawblade differentiating the Carcinogenic Equivalency (TEQ) of investigated materials and their PM fractions. Furthermore, derivatives of BPA occurred in abrasive dust from C3 reinforcement materials potentially leading to genotoxicity and reproductive toxicity.

Information Analytical Calculation and Construction of Dispersion Maps of Pollutants in the Surface Layer of the Atmosphere at a Specialized Facility

We carried out an environmental audit on the territory of a specialized facility of all sources of environmental pollution and, accordingly, we measured the concentration of polluting components embodied in the atmospheric background. As a result of the inventory of emission sources, we recorded the following picture for the total emissions of pollutants into the air zone of the facility: 1.647832 t/year, including 1.597435 t/year in the liquid and gaseous state, and 0.050397 t/year in the solid state. We present the calculation of pollution from generators of emissions of the air zone of the facility, which is recorded on the basis of the Unified Atmospheric Pollution Calculation Program (UAPCP) “Ecolog” (version 3.0). According to the feasibility study, the dispersion calculation was recognized as socially effective for site 2 (hangar) - for NO2, NO, kerosene, CO, SO2, and abrasive dust. We calculated the surface concentrations of harmful substances in the atmosphere and constructed dispersion maps for the object for the winter period. The implemented research showed that the accumulation of contaminants does not reach the standard values of concentrations at key points suitable for determination at the boundary of the sanitary protection zone and the residential area. The dispersion calculation indicators showed that the predominant fraction of all diffusing contaminants for the hangar in the sanitary protection zone is NO2 0.82 parts of the maximum permissible concentration with and without background 0.697, and in the residential area, 0.11 parts of MPC without background.

Research of abrasive properties separate dust to ensure the reliability of dusting systems in the production of building materials

The intensive development of the infrastructure of large cities, which took place in the second half of the twentieth century, led to the fact that enterprises specializing in the production of building materials and products were in close proximity to urban residential areas. This determines an increase in the requirements for the efficiency and reliability of dust removal systems designed, as is known, to ensure the standardized quality of the air environment of settlements and industrial premises. The dust generated in the production of building materials, in many cases, has abrasive properties, which leads to accelerated wear of the elements of dust cleaning systems. The experience of using such systems shows that dust collectors, as well as shaped parts of air ducts (bends, tees, etc.), through which the dust and gas mixture is transported to dust collectors, are most susceptible to abrasion. Abrasive wear of dust collectors during operation leads to an increase in dust leakage into the atmospheric air into the air of the working area. During operation of a dust-cleaning unit under pressure, damage to the walls of the air ducts also leads to knocking out the transported dust. The supercritical wear of the elements of the dust removal system leads to its failure. The article presents some results of studies of the dust properties of building materials that determine the process of abrasive wear.