scholarly journals Combining NSAM and CPC concentrations to determine airborne nanoparticle count median diameter: Application to various laboratory and workplace aerosols

2018 ◽  
Vol 15 (6) ◽  
pp. 492-501
Author(s):  
S. Bau ◽  
R. Payet ◽  
A. Toussaint ◽  
O. Witschger ◽  
A.M. Todea ◽  
...  
Keyword(s):  
Median Diameter ◽  
Count Median Diameter ◽  
Airborne Nanoparticle

Count Median Diameter

2016 ◽  
Author(s):  
John H. Duffus ◽  
Monica Nordberg ◽  
Douglas M. Templeton
Keyword(s):  
Median Diameter ◽  
Count Median Diameter

Alveolar clearance in dogs after inhalation of an iron 59 oxide aerosol

1962 ◽  
Vol 17 (3) ◽  
pp. 429-432 ◽  
Author(s):  
F. R. Gibb ◽  
P. E. Morrow
Keyword(s):  
Standard Deviation ◽  
Respiratory Tract ◽  
Clearance Rate ◽  
Geometric Standard Deviation ◽  
Probe Type ◽  
Half Time ◽  
Average Value ◽  
Biological Half Time ◽  
Median Diameter ◽  
Count Median Diameter

Six dogs each received two 60-min exposures, 6 months apart, to an aerosol of iron 59 oxide, having an average count median diameter of 0.09 μ and a geometric standard deviation of 1.8. The concentration of iron 59 in the inspired air ranged between 0.004–0.017 μc/liter. Lung measurements were made immediately after each exposure and up to 30 days postexposure. This procedure was followed in both initial and repeat exposures of each dog. A probe-type scintillation detector fitted with a focusing collimator was used to limit the measurements to specific respiratory tract positions on each dog. The biological half-time for alveolar clearance in the 12 studies ranged from 44 to 82 days with an average value of 62 days (sd 8.8 days). This consistency suggests the probability of a normal clearance rate and the possibility of its use as a functional test. Submitted on July 11, 1961

Supramicron-sized particle clearance from alveoli: route and kinetics

1990 ◽  
Vol 69 (4) ◽  
pp. 1302-1308 ◽  
Author(s):  
E. G. Langenback ◽  
E. H. Bergofsky ◽  
J. G. Halpern ◽  
W. M. Foster
Keyword(s):  
Lymphatic Drainage ◽  
Lung Lavage ◽  
Tracheobronchial Tree ◽  
Scintillation Camera ◽  
Balance Study ◽  
Whole Lung Lavage ◽  
Particle Clearance ◽  
Median Diameter ◽  
Count Median Diameter ◽  
Kinetics Of

Particles inhaled and deposited in the alveoli of the lung, i.e., distal to the tracheobronchial mucociliary escalator, may theoretically be cleared by several routes, including solubilization, lymphatic drainage, and the mucociliary pathway. We studied the clearance routes and kinetics of an inert insoluble carbonized polystyrene particle of supramicron size (2.85 micron count median diameter) tagged with 57Co (half-life 270 days) in the adult unanesthetized sheep. The rate of particle clearance, assessed by gamma scintillation camera of the whole lung, showed a three-exponential function, comprising a rapid initial phase in the first 44 h of clearance for tracheobronchial deposition followed by a slower phase of mostly alveolar clearance in the next 30 days and a final phase of very slow relatively pure alveolar clearance. A balance study of particle route during clearance and autopsy of regional thoracic lymph nodes, blood, liver, and spleen demonstrated that this supramicron-sized particle cleared from alveoli predominantly via the mucociliary escalator of the tracheobronchial tree. Whole-lung lavage studies showed particle and macrophage recovery rates suggesting a sequestered state for alveolar-deposited particles, which may partly account for their slow clearance rates. The failure to find interstitial penetration by alveolar-deposited particles indicates that the macrophages engulfing these particles, at low particle burdens, travel normally in only one direction, i.e., from interstitium to alveolus and then to the mucociliary escalator.

Count Median Diameter

2016 ◽  
Author(s):  
Monica Nordberg ◽  
John H. Duffus ◽  
Douglas M. Templeton
Keyword(s):  
Median Diameter ◽  
Count Median Diameter

scholarly journals Biomass burning aerosol emissions from vegetation fires: particle number and mass emission factors and size distributions

2009 ◽  
Vol 9 (4) ◽  
pp. 17183-17217 ◽  
Author(s):  
S. Janhäll ◽  
M. O. Andreae ◽  
U. Pöschl
Keyword(s):  
Particle Number ◽  
Combustion Efficiency ◽  
Emission Factors ◽  
Fuel Type ◽  
Vegetation Fires ◽  
Fitting Procedures ◽  
Median Diameter ◽  
Count Median Diameter ◽  
Biomass Burning Aerosol ◽  
Aerosol Emissions

Abstract. Aerosol emissions from vegetation fires have a large impact on air quality and climate. In this study, we use published experimental data and different fitting procedures to derive dynamic particle number and mass emission factors (EFPN, EFPM) related to the fuel type, burning conditions and the mass of dry fuel burned, as well as characteristic CO-referenced emission ratios (PN/CO, PM/CO). Moreover, we explore and characterize the variability of the particle size distribution of fresh smoke, which is typically dominated by a lognormal accumulation mode with count median diameter around 120 nm (depending on age, fuel and combustion efficiency), and its effect on the relationship between particle number and mass emission factors. For the particle number emission factor of vegetation fires, we found no dependence on fuel type and obtained the following parameterization as a function of modified combustion efficiency (MCE): EFPN=34·1015×(1-MCE) kg−1±1015 kg−1 with regard to dry fuel mass (d.m.). For the fine particle mass emission factors (EFPM) we obtained (86–85×MCE) g kg−1±3 g kg−1 as an average for all investigated fires; (93–90×MCE) g kg

An Experimental Study on the Particle Concentration and Size Distribution of Smoke Generated by Flaming N-Heptane

2013 ◽  
Vol 391 ◽  
pp. 61-65 ◽  
Author(s):  
Yao Dong Li ◽  
Du Chen ◽  
Feng Wang ◽  
Wei Yuan ◽  
Qi Xing Zhang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Size Distribution ◽  
Particle Concentration ◽  
Particle Number ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
Buoyant Plume ◽  
Change Rate ◽  
Median Diameter ◽  
Count Median Diameter

The particles of smoke generated by flaming n-heptane was measured by Fast Particulate Spectrometer (DMS500), and the particle number concentration and size distribution were recorded and analyzed for investigating the smoke dynamic characteristics. The experimental results indicated that the particle number concentrations of buoyant plume above the flame approximately decrease with the height. At the center of ceiling, there is an approximate linear relationship between the particle number concentration and heat release rate. The count median diameter (CMD) varies with time and the change rate of CMD varies with particle concentration. In these experiments, the CMD is a constant in a few minutes after burning extinction.

A magnetic super lattice

1987 ◽  
Vol 45 ◽  
pp. 360-361 ◽  
Author(s):  
M.D. Bentzon ◽  
J. v. Wonterghem ◽  
A. Thölén
Keyword(s):  
Thermal Decomposition ◽  
Oleic Acid ◽  
Magnetic Fluid ◽  
Magnetic Particles ◽  
Carbon Film ◽  
Thick Layer ◽  
Amorphous Iron ◽  
Super Lattice ◽  
Carrier Liquid ◽  
Median Diameter

We report on the oxidation of a magnetic fluid. The oxidation results in magnetic super lattice crystals. The “atoms” are hematite (α-Fe2O3) particles with a diameter ø = 6.9 nm and they are covered with a 1-2 nm thick layer of surfactant molecules.Magnetic fluids are homogeneous suspensions of small magnetic particles in a carrier liquid. To prevent agglomeration, the particles are coated with surfactant molecules. The magnetic fluid studied in this work was produced by thermal decomposition of Fe(CO)5 in Declin (carrier liquid) in the presence of oleic acid (surfactant). The magnetic particles consist of an amorphous iron-carbon alloy. For TEM investigation a droplet of the fluid was added to benzine and a carbon film on a copper net was immersed. When exposed to air the sample starts burning. The oxidation and electron irradiation transform the magnetic particles into hematite (α-Fe2O3) particles with a median diameter ø = 6.9 nm.

Assessment of Duodenal Diverticula: Computed Tomography Findings

2019 ◽  
Vol 15 (10) ◽  
pp. 948-955
Author(s):  
Erdem Yilmaz ◽  
Osman Kostek ◽  
Savas Hereklioglu ◽  
Muhammet Goktas ◽  
Nermin Tuncbilek
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Ampulla Of Vater ◽  
Common Type ◽  
Radiological Features ◽  
New Findings ◽  
Duodenal Diverticula ◽  
Median Diameter ◽  
Colonic Diverticula

Aims: To demonstrate the prevalence, accompanying pathologies, imaging and follow up findings of Duodenal Diverticula (DD) with Multidetector Computed Tomography (MDCT). Materials and Methods: Consecutive 2910 abdominal MDCTs were retrospectively reviewed on axial, coronal and sagittal planes. DD were evaluated for prevalence, location, number, size, contents, diverticular neck, accompanying pancreaticobiliary pathologies, jejunal and colonic diverticula, respectively. Results: DD were diagnosed in 157 cases (5.4%) and found mostly in the second part of the duodenum. Juxta-ampullary DD was the most common type (78.3%) and mostly located ventral (n:86, 69.9%) to the ampulla of Vater. DD was solitary in 123 patients (78.3%) and more than one in 34 patients (21.7%). The median diameter of DD was 2.5 cm (range 1.5-3.6 cm) in the long-axis. The lumen of DD contains air and contrast agent (n:96, 61.1%); air, contrast agent and debris (n:42, 26.7%) in most cases. Colonic diverticula (n:36, 22.9%), cholelithiasis (n:32, 20.4%), choledocholithiasis (n:7, 4.4%), and biliary dilatation (n:8, 5.1%) were the most common additional findings. Median follow-up time was 23 months (range 11 to 41 months). In three cases, new findings (cholelithiasis, n:3, choledocholithiasis, n:1) were detected. Conclusion: Accompanying pathologies with DD diagnosis are valuable for physicians in order to manage the patients. Following clinical and radiological features of well-diagnosed DD might reduce the possible complications.

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