A Study of Airborne Wear Particles Generated From a Sliding Contact

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Ulf Olofsson ◽  
Lars Olander ◽  
Anders Jansson
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Urban Environments ◽  
Airborne Particles ◽  
Wear Particles ◽  
Coarse Particles ◽  
Sliding Velocity ◽  
Airborne Particle ◽  
Particle Generation ◽  
Pin On Disk

Recently, much attention has been paid to the influence of airborne particles in the atmosphere on human health. Sliding contacts are a significant source of airborne particles in urban environments. In this study airborne particles generated from a sliding steel-on-steel combination are studied using a pin-on-disk tribometer equipped with airborne-particle counting instrumentation. The instrumentation measured particles in size intervals from 0.01μm to 32μm. The result shows three particle size regimes with distinct number peaks: ultrafine particles with a size distribution peak around 0.08μm, fine particles with a peak around 0.35μm, and coarse particles with a peak around 2 or 4μm. Both the particle generation rate and the wear rate increase with increasing sliding velocity and contact pressure.

Particle emission of organic brake pad material: A review

2019 ◽  
Vol 234 (5) ◽  
pp. 1213-1223
Author(s):  
Santosh Kumar ◽  
Subrata Kumar Ghosh
Keyword(s):  
Composite Materials ◽  
Ultrafine Particles ◽  
Volume Fraction ◽  
Particle Emission ◽  
Airborne Particles ◽  
Wear Particles ◽  
Brake Pad ◽  
Scanning Mobility Particle Sizer ◽  
Particle Sizer ◽  
Near Future

Wear of a brake pad emits airborne particles and is a major environmental issue. This review paper deals with the analysis of different brake pad composite materials and their wear phenomenon. The volume fraction and size distribution of non-asbestos organic airborne particles emitted from the brake pad material with time, load and speed have also been discussed under different braking conditions. The airborne particles are measured by different aerosol instruments. TSI P-Trak, GRIMM aerosol spectrometer and scanning mobility particle sizer were used by different researchers for measuring ultrafine particles, micron-sized particles and aerodynamic nanoparticles, respectively. This paper shows that the wear particles emitted from the brake pad material vary in diameter between 10 nm and 10 μm under various loads and sliding velocities. These airborne particles such as coarse fine (diameters > 1 μm), fine (diameters between 100 nm and 1 μm) and ultrafine (diameters < 100 nm) particles are responsible for health hazards to the human respiratory system. This study has accumulated the data of different ingredients of the brake pad with airborne particle emission from various studies, which may be helpful for the evolution of new composite materials in the near future.

scholarly journals Effects of carbonaceous materials and particle size on oral and inhalation bioaccessibility of PAHs and OPEs in airborne particles

2021 ◽  
Author(s):  
Yuan Zeng ◽  
shejun Chen ◽  
Yun Fan ◽  
Qiqi Li ◽  
Yufeng Guan ◽  
...  
Keyword(s):  
Particle Size ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Airborne Particles ◽  
Coarse Particles ◽  
Strongly Correlated ◽  
Oral Bioaccessibility ◽  
Polycyclic Aromatic ◽  
Potential Factors ◽  
Scientific Attention

Abstract Bioavailability of environmental contaminants is attracting considerable scientific attention due to growing awareness of its importance for risk assessment. In this study, potential factors governing bioaccessibility of airborne particles-bound polycyclic aromatic hydrocarbons (PAHs) and organophosphorus esters (OPEs) in stimulated gastrointestinal and respiratory tracts were elucidated. Particle concentrations of PAHs and OPEs at the eight sites were 2.4−32.3 ng/m3 and 1.6−19.9 ng/m3, respectively. In fine particles (with aerodynamic diameter less than 2.5 µm), 4- to 6-ring PAHs were more strongly correlated with organic carbon (OC) than elemental carbon (EC); while 3- and 4-ring PAHs in coarse particles (2.5−10 µm) tended to associate with EC. OPEs mostly showed significant correlations with EC in both fine and coarse particles. OC and EC exerted a significantly restraining effect on the oral and inhalation bioaccessibility of most HOCs in fine particles due to sorption of HOC molecules to these components. Furthermore, the effects varied, which could depend either on the emission sources (for oral bioaccessibility of PAHs) or the physicochemical properties of HOCs (for bioaccessibility of OPEs and inhalation bioaccessibility of PAHs). Linear regression indicated that EC should play a more important role in the inhalation bioaccessibility than the oral bioaccessibility. Particle size of airborne particles is a relatively less significant factor determining the bioaccessibility.

scholarly journals Reducing the nanoparticles generated at the wheel–rail contact by applying tap water lubricant at subway train operational velocities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
HyunWook Lee
Keyword(s):  
Water Vapor ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Tap Water ◽  
Slip Rate ◽  
Number Concentration ◽  
Particle Generation ◽  
Dry Conditions ◽  
Subway Train ◽  
Water Lubricant

AbstractThe formation characteristics and the reduction of nanoparticles emitted from wheel–rail contacts at subway-train velocities of 73, 90, and 113 km/h under dry and water-lubricated conditions (using tap water) were studied using a twin-disk rig. The resulting number concentration (NC) of ultrafine and fine particles increased with train velocity under both conditions. Particle generation varied with slip rate under both conditions in both the particle categories. Furthermore, the formation characteristics at 113 km/h under dry conditions showed a notable deviation from those under water-lubricated conditions in three aspects: (i) The maximum NC of ultrafine particles was higher than that of fine particles, (ii) the predominant peak diameter was in the ultrafine particles category, and (iii) the proportion of ultrafine particles was much higher than those of the fine particles. Applying water decreased the NC of ultrafine and fine particles significantly at all tested velocities (by 54–69% and 87–91%, respectively). Adding water increased the NC of particles ≤ 35 nm in diameter, possibly owing to the increase in water vapor and mineral crystals from tap water. Overall, this study provides a reference for researchers aiming to minimize nanoparticle formation at the wheel–rail contacts by applying a lubricant.

scholarly journals Reduction the Nanoparticles Generated at the Wheel–rail Contact by Applying Tap Water Lubricant at Subway Train Operational Velocities1

2021 ◽  
Author(s):  
HyunWook Lee
Keyword(s):  
Water Vapor ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Tap Water ◽  
Slip Rate ◽  
Number Concentration ◽  
Particle Generation ◽  
Dry Conditions ◽  
Subway Train ◽  
Water Lubricant

Abstract The formation characteristics and reduction of nanoparticles emitted from wheel–rail contacts at subway train velocities of 73, 90, and 113 km/h under dry and water-lubricated conditions (using tap water) were studied using a twin-disk rig. The resulting number concentration (NC) of ultrafine and fine particles increased with train velocity under both conditions. Particle generation varied with slip rate under both conditions in both the particle categories studied. Further, the formation characteristics at 113 km/h under dry conditions showed a notable deviation from those under water-lubricated conditions in three aspects: (i) the maximum NC of ultrafine particles was higher than that of fine particles, (ii) the predominant peak diameter was in the ultrafine particles category, and (iii) the proportion of ultrafine particles was much higher than those of fine particles. Applying water decreased the NC of ultrafine and fine particles significantly at all tested velocities (by 54%–69% and 87%–91%, respectively). Adding water increased the NC of particles ≤35 nm in diameter, possibly owing to the increase in water vapor and mineral crystals from tap water. Overall, this study provides a reference for researchers aiming to minimize nanoparticle formation at the wheel–rail contacts by applying a lubricant.

scholarly journals Assessment of mask efficiency for preventing transmission of airborne illness through aerosols and water vapor

2021 ◽  
Vol 5 ◽  
pp. 105
Author(s):  
Coral N. Ringer ◽  
Rebecca J. Engberg ◽  
Kristen E. Carlin ◽  
Kellie J. Micheletti ◽  
Dianna L. Shankland ◽  
...  
Keyword(s):  
Water Vapor ◽  
Fine Particles ◽  
Filter Material ◽  
Airborne Particles ◽  
Lung Model ◽  
Coarse Particles ◽  
Test Lung ◽  
Testing Conditions ◽  
The Face ◽  
Coarse Aerosol

Background: Currently the Center for Disease Control has advised the use of face coverings to prevent transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to those who are unvaccinated. This study seeks to evaluate if cloth masks have increased efficiency with the addition of a filter material. Methods: An adult airway and test lung model were exposed to nebulized ‘coarse’ aerosol droplets (0.5-11 µm) and humidified ‘fine’ water vapor particles (0.03-0.05 µm). Aerosol was quantified based on particles deposited on the face, airway and lung model. Tracheal humidity levels characterized fine particle permeability. Both phases of testing were conducted by evaluating the following testing conditions: 1) no mask; 2) cloth mask; 3) cloth mask with Swiffer™ filter; 4) cloth mask with Minimum Efficiency Reporting Value (MERV) 15 filter; 4) cloth mask with PM2.5 filter 5) surgical mask and 6) N95 respirator. Results: All mask conditions provided greater filtration from coarse particles when compared to no mask (P<0.05). All cloth mask with filter combinations were better at stopping fine particles in comparison to no mask. A cloth mask without a filter and surgical mask performed similarly to no mask with fine particles (P<0.05). The cloth mask with MERV 15 filter and the surgical mask performed similarly to the N95 with course particles, while the cloth mask with Swiffer™ performed similarly to the N95 with the fine particles (P<0.05). Conclusions: Respiratory viruses including SARS-CoV-2 and influenza are spread through exposure to respiratory secretions that are aerosolized by infected individuals. The findings from this study suggest that a mask can filter these potentially infectious airborne particles.

Studies of copper selenide ultrafine particles by newly developed gas evaporation method

1990 ◽  
Vol 48 (4) ◽  
pp. 306-307
Author(s):  
Chihiro Kaito ◽  
Yoshio Saito
Keyword(s):  
Crystal Structure ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Production Method ◽  
Atmospheric Temperature ◽  
Copper Selenide ◽  
Quartz Boat ◽  
Selenium Vapor ◽  
Ar Gas ◽  
Ultra Fine Particles

The direct evaporation of metallic oxides or sulfides does not always given the same compounds with starting material, i.e. decomposition took place. Since the controll of the sulfur or selenium vapors was difficult, a similar production method for oxide particles could not be used for preparation of such compounds in spite of increasing interest in the fields of material science, astrophysics and mineralogy. In the present paper, copper metal was evaporated from a molybdenum silicide heater which was proposed by us to produce the ultra-fine particles in reactive gas as shown schematically in Figure 1. Typical smoke by this method in Ar gas at a pressure of 13 kPa is shown in Figure 2. Since the temperature at a location of a few mm below the heater, maintained at 1400° C , were a few hundred degrees centigrade, the selenium powder in a quartz boat was evaporated at atmospheric temperature just below the heater. The copper vapor that evaporated from the heater was mixed with the stream of selenium vapor,and selenide was formed near the boat. If then condensed by rapid cooling due to the collision with inert gas, thus forming smoke similar to that from the metallic sulfide formation. Particles were collected and studied by a Hitachi H-800 electron microscope.Figure 3 shows typical EM images of the produced copper selenide particles. The morphology was different by the crystal structure, i.e. round shaped plate (CuSe;hexagona1 a=0.39,C=l.723 nm) ,definite shaped p1 ate(Cu5Se4;Orthorhombic;a=0.8227 , b=1.1982 , c=0.641 nm) and a tetrahedron(Cu1.8Se; cubic a=0.5739 nm). In the case of compound ultrafine particles there have been no observation for the particles of the tetrahedron shape. Since the crystal structure of Cu1.8Se is the anti-f1uorite structure, there has no polarity.

scholarly journals Contribution of Fine Particles to Air Emission at Different Phases of Biomass Burning

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 278 ◽  
Author(s):  
Niloofar Ordou ◽  
Igor E. Agranovski
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Fine Particles ◽  
Combustion Process ◽  
Coarse Particles ◽  
Biomass Smoke ◽  
Smoke Particles ◽  
Air Emission ◽  
Entire Duration ◽  
Diffusion Properties

Particle size distribution in biomass smoke was observed for different burning phases, including flaming and smouldering, during the combustion of nine common Australian vegetation representatives. Smoke particles generated during the smouldering phase of combustions were found to be coarser as compared to flaming aerosols for all hard species. In contrast, for leafy species, this trend was inversed. In addition, the combustion process was investigated over the entire duration of burning by acquiring data with one second time resolution for all nine species. Particles were separately characterised in two categories: fine particles with dominating diffusion properties measurable with diffusion-based instruments (Dp < 200 nm), and coarse particles with dominating inertia (Dp > 200 nm). It was found that fine particles contribute to more than 90 percent of the total fresh smoke particles for all investigated species.

Vaporization and Ultra-Fine Particle Generation during the Plasma Spraying Process

1997 ◽  
Author(s):  
K.A. Gross ◽  
P. Fauchais ◽  
M. Vardelle ◽  
J. Tikkanen ◽  
J. Keskinen
Keyword(s):  
Fine Particles ◽  
High Concentration ◽  
Thermal Spray Process ◽  
Particle Generation ◽  
Spray Process ◽  
Ultra Fine Particle ◽  
Fast Cooling ◽  
Ultra Fine Particles ◽  
Plasma Spraying Process ◽  
Very High

Abstract The thermal spray process melts powder at very high temperatures and propels the molten material to the substrate to produce a coherent deposit. This heating produces a certain amount of vaporization of the feedstock. Upon exiting the plasma plume the fast cooling conditions lead to condensation of the vapor. An electrical low pressure impactor was used to monitor the concentration of ultra-fine particles at various radial and axial distances. Metal, namely iron powder, showed very high concentration levels which increase with distance. Ultra-fine particles from ZrO2-8Y2O3 reached a peak concentration at 6 cm. Use of an air barrier during spraying decreases the population of ultra-fine particles facilitating the production of a stronger coating.

scholarly journals Study of the Lubricating Ability of Protic Ionic Liquid on an Aluminum–Steel Contact

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 66 ◽  
Author(s):  
Akshar Patel ◽  
Hong Guo ◽  
Patricia Iglesias
Keyword(s):  
Ionic Liquid ◽  
Friction And Wear ◽  
Constant Load ◽  
Economic Losses ◽  
Contact Friction ◽  
Wear Volume ◽  
Sliding Velocity ◽  
Protic Ionic Liquid ◽  
Wear Reduction ◽  
Pin On Disk

Contact friction between moving components leads to severe wear and failure of engineering parts, resulting in large economic losses. The lubricating ability of the protic ionic liquid, tri-[bis(2-hydroxyethylammonium)] citrate (DCi), was studied as a neat lubricant and as an additive in a mineral oil (MO) at various sliding velocities and constant load on an aluminum–steel contact using a pin-on-disk tribometer. Tribological tests were also performed at different concentrations of DCi. When DCi was used as an additive in MO, friction coefficient and wear volume were reduced for each sliding velocity, with a maximum friction and wear reduction of 16% and 40%, respectively, when 2 wt % DCi was added to MO at a sliding velocity of 0.15 m/s. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were also applied to analyze the wear mechanism of the interface lubricated by MO and DCi as additive.

Sign in / Sign up

Export Citation Format

Share Document