scholarly journals Characterization of Airborne Particles Emitted During Application of Cosmetic Talc Products

2019 ◽  
Vol 16 (20) ◽  
pp. 3830 ◽  
Author(s):  
Pat Rasmussen ◽  
Christine Levesque ◽  
Jianjun Niu ◽  
Howard Gardner ◽  
Gregory Nilsson ◽  
...  
Keyword(s):  
Particle Size ◽  
Consumer Products ◽  
Airborne Particles ◽  
Aerodynamic Diameter ◽  
Breathing Zone ◽  
Direct Reading ◽  
Detailed Characterization ◽  
Adult Body ◽  
Reading Instruments

A pilot study was undertaken to characterize the concentration, duration and particle size distribution of the talc cloud that forms in the personal breathing zone (PBZ) during application of certain talc-containing cosmetics. Multiple direct-reading instruments were employed to simultaneously monitor PM4 concentrations (particulate matter with aerodynamic diameter < 4 µm; mg/m3) at different distances from each of three subjects while they applied talc products. Results indicated that the purpose and method of applying the talc product, combined with behavioral and physical differences amongst subjects, all strongly influenced airborne talc concentrations and the duration of the cloud. Air concentrations of talc in the PBZ averaged around 1.0 mg/m3, and the duration of exposure varied from less than one minute to more than ten minutes. The real-time monitors captured the occasional formation of secondary clouds, likely caused by resuspension of talc particles from skin or other surfaces. Measurements of aerosolized baby powder, face powder, and two adult body powders indicated that the median aerodynamic diameter of the talc cloud ranged from 1.7 to 2.0 µm. These direct-reading approaches were valuable for providing detailed characterization of short duration exposures to airborne talc particles, and will be useful to support future exposure assessments of talc and other powders in consumer products.

Size distribution and single particle characterization of airborne particulate matter collected in a silicon carbide plant

2019 ◽  
Vol 21 (3) ◽  
pp. 564-574 ◽  
Author(s):  
Torunn Kringlen Ervik ◽  
Nathalie Benker ◽  
Stephan Weinbruch ◽  
Yngvar Thomassen ◽  
Dag G. Ellingsen ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Particulate Matter ◽  
Size Range ◽  
Airborne Particulate Matter ◽  
Aerodynamic Diameter ◽  
Particle Characterization ◽  
Airborne Particulate ◽  
Detailed Characterization

A detailed characterization of particles as a function of particle size in the size range of 10 nm to 10 µm (aerodynamic diameter) collected from a silicon carbide plant in Norway.

Direct characterization of airborne particles associated with arsenic-rich mine tailings: Particle size, mineralogy and texture

2011 ◽  
Vol 26 (9-10) ◽  
pp. 1639-1648 ◽  
Author(s):  
M.C. Corriveau ◽  
H.E. Jamieson ◽  
M.B. Parsons ◽  
J.L. Campbell ◽  
A. Lanzirotti
Keyword(s):  
Particle Size ◽  
Mine Tailings ◽  
Airborne Particles

scholarly journals Characterization of Aerosol Nebulized by Aerogen Solo Mesh Nebulizer

2020 ◽  
Vol 328 ◽  
pp. 01006
Author(s):  
Ondrej Misik ◽  
Milan Maly ◽  
Ondrej Cejpek ◽  
Frantisek Lizal
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Aerodynamic Diameter ◽  
Jet Nebulizers ◽  
Mass Median

Nebulizers are commonly used devices for inhalation treatment of various disorders. There are three main categories of medical nebulization technology: jet nebulizers, ultrasound nebulizer, and mesh nebulizer. The mesh nebulizers seem to be very promising since this technology should be able to produce aerosol with precisely determined particle size and is easy to use as well [1]. Aerosol generated from the mesh nebulizer Aerogen Solo was measured in this work. Particle size distribution with a mass median of aerodynamic diameter (MMAD) was determined by two different methods.

scholarly journals Workplace Emissions and Exposures During Semiconductor Nanowire Production, Post-production, and Maintenance Work

2019 ◽  
Vol 64 (1) ◽  
pp. 38-54 ◽  
Author(s):  
Christina Isaxon ◽  
Karin Lovén ◽  
Linus Ludvigsson ◽  
Sudhakar Sivakumar ◽  
Anders Gudmundsson ◽  
...  
Keyword(s):  
Arc Discharge ◽  
Number Concentration ◽  
Breathing Zone ◽  
Direct Reading ◽  
Potential Health ◽  
Semiconductor Nanowire ◽  
Wide Range ◽  
Work Tasks ◽  
Post Production ◽  
Reading Instruments

Abstract Background Nanowires are a high-aspect-ratio material of increasing interest for a wide range of applications. A new and promising method to produce nanowires is by aerotaxy, where the wires are grown in a continuous stream of gas. The aerotaxy method can grow nanowires much faster than by more conventional methods. Nanowires have important properties in common with asbestos fibers, which indicate that there can be potential health effects if exposure occurs. No conclusive exposure (or emission) data from aerotaxy-production of nanowires has so far been published. Methods Different work tasks during semiconductor nanowire production, post-production, and maintenance were studied. A combination of direct-reading instruments for number concentration (0.007–20 µm) and filter sampling was used to assess the emissions (a couple of centimeter from the emission sources), the exposure in the personal breathing zone (max 30 cm from nose–mouth), and the concentrations in the background zone (at least 3 m from any emission source). The filters were analyzed for metal dust composition and number concentration of nanowires. Various surfaces were sampled for nanowire contamination. Results The particle concentrations in the emission zone (measured with direct-reading instruments) were elevated during cleaning of arc discharge, manual reactor cleaning, exchange of nanowire outflow filters, and sonication of substrates with nanowires. In the case of cleaning of the arc discharge and manual reactor cleaning, the emissions affected the concentrations in the personal breathing zone and were high enough to also affect the concentrations in the background. Filter analysis with electron microscopy could confirm the presence of nanowires in some of the air samples. Conclusions Our results show that a major part of the potential for exposure occurs not during the actual manufacturing, but during the cleaning and maintenance procedures. The exposures and emissions were evaluated pre- and post-upscaling the production and showed that some work tasks (e.g. exchange of nanowire outflow filters and sonication of substrates with nanowires) increased the emissions post-upscaling.

Influence of Hydrothermal Nanosilica on Mechanical Properties of Plain Concrete

2017 ◽  
Vol 744 ◽  
pp. 126-130 ◽  
Author(s):  
Natalya Valentinovna Makarova ◽  
Vadim V. Potapov ◽  
Andrey V. Kozin ◽  
Evgeniy Anatolievich Chusovitin ◽  
Andrey V. Amosov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Lower Energy ◽  
Volume Fraction ◽  
Concrete Strength ◽  
Hydrothermal Solution ◽  
Plain Concrete ◽  
Energy Requirements ◽  
Detailed Characterization

The production of nanosilica (NS) from natural hydrothermal solution is an alternative to the existing commercial fabrication methods because of the lower energy requirements. Here we provide a detailed characterization of the main properties of NS samples (e.g., shape and particle size) by different methods. The produced NS has a specific surface area between 60 m2/g and 500 m2/g and nanoparticles sizes between 5 nm and 135 nm. The aim of the present work is to evaluate the effect of the natural NS on compressive strengths of plain concrete. For this purpose, eight series of concrete specimens with different volume fraction of NS are studied. Experimental results reveal that with adding of NS, the concrete strength can be increased by 35% after 28 days, whereas strength characteristics of such concrete can be increased up to 84% after 3 days, and 93% after 7 days compared with a control concrete without NS.

Incorporation of micro/nanoparticles of PCL with essential oil of Cymbopogon nardus in bacterial cellulose

2018 ◽  
Vol 1 (2) ◽  
pp. 37
Author(s):  
Aline Krindges ◽  
Vanusca Dalosto Jahno ◽  
Fernando Morisso
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Essential Oil ◽  
Zeta Potential ◽  
Bacterial Cellulose ◽  
Culture Medium ◽  
Static Culture ◽  
Cymbopogon Nardus ◽  
Cellulose Membranes

Incorporation studies of particles in different substrates with herbal assets growing. The objective of this work was the preparation and characterization of micro/nanoparticles containing cymbopogon nardus essential oil; and the incorporation of them on bacterial cellulose. For the development of the membranes was used the static culture medium and for the preparation of micro/nanoparticles was used the nanoprecipitation methodology. The incorporation of micro/nanoparticles was performed on samples of bacterial cellulose in wet and dry form. For the characterization of micro/nanoparticles were carried out analysis of SEM, zeta potential and particle size. For the verification of the incorporation of particulate matter in cellulose, analyses were conducted of SEM and FTIR. The results showed that it is possible the production and incorporation of micro/nanoparticles containing essential oil in bacterial cellulose membranes in wet form with ethanol.

Intramolecular Proton Transfer in the Isomerization of Hydroxyacetone: A Detailed Characterization Based on Reaction Force Analysis and the Bond Fragility Spectrum

2020 ◽  
Author(s):  
Wallace Derricotte ◽  
Huiet Joseph
Keyword(s):  
Chemical Potential ◽  
Reaction Force ◽  
Intramolecular Proton Transfer ◽  
Intermediate Energy ◽  
Force Analysis ◽  
Activation Energy Barrier ◽  
Detailed Characterization ◽  
Proton Transfers ◽  
Reaction Force Constant

The mechanism of isomerization of hydroxyacetone to 2-hydroxypropanal is studied within the framework of reaction force analysis at the M06-2X/6-311++G(d,p) level of theory. Three unique pathways are considered: (i) a step-wise mechanism that proceeds through formation of the Z-isomer of their shared enediol intermediate, (ii) a step-wise mechanism that forms the E-isomer of the enediol, and (iii) a concerted pathway that bypasses the enediol intermediate. Energy calculations show that the concerted pathway has the lowest activation energy barrier at 45.7 kcal mol<sup>-1</sup>. The reaction force, chemical potential, and reaction electronic flux are calculated for each reaction to characterize electronic changes throughout the mechanism. The reaction force constant is calculated in order to investigate the synchronous/asynchronous nature of the concerted intramolecular proton transfers involved. Additional characterization of synchronicity is provided by calculating the bond fragility spectrum for each mechanism.

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