Absolute measurement of high particle number concentrations by simultaneous observation of extinction and scattered laser light

1990 ◽  
Author(s):  
Wladyslaw W. Szymanski ◽  
Paul E. Wagner
Keyword(s):  
Particle Number ◽  
Laser Light ◽  
Absolute Measurement ◽  
Simultaneous Observation ◽  
High Particle

Spectral Element Simulation of Complex Particulate Flows

2013 ◽  
Vol 404 ◽  
pp. 318-323 ◽  
Author(s):  
Don Liu ◽  
Yi Fan Wang ◽  
Hai Bo Zhang
Keyword(s):  
Particle Number ◽  
Computational Cost ◽  
Salient Feature ◽  
Spectral Element ◽  
Particle Number Density ◽  
Particulate Flows ◽  
Two Phase ◽  
Variable Source ◽  
High Particle ◽  
Element Simulation

This paper uses a mathematical model Virtual Identity Particles, developed by the author, to simulate conjugated motion of complex particles in a fluid. Assimilated the advantages of Eulerian and Lagrangian approaches, this model treats each particle as a variable source term to the fluid and is designed for simulating numerous particles in two-phase flows. The economic formulation in this model is the salient feature. Considering both precision and computational cost, this model maintains an excellent balance between accuracy and efficiency in modeling particulate flows with complex particles. Simulation results demonstrate that this model is viable for investigating complex particulate flows, especially at a moderately high particle number density.

scholarly journals Iron Kα Spectra from an Atomic Modeling Perspective

2005 ◽  
Vol 13 ◽  
pp. 630-632
Author(s):  
Duane A. Liedahl
Keyword(s):  
Particle Number ◽  
Collisional Excitation ◽  
X Ray ◽  
Atomic Models ◽  
High Particle ◽  
Diagnostic Capability

AbstractIn order to upgrade the diagnostic capability associated with Fe Kα spectra, we have calculated detailed atomic models that include the effects of inner-shell photoionization, autoionization, collisional excitation at relatively high particle number densities, and photoexcitation in plasmas with high X-ray and/or UV energy densities. I discuss some of the potential uses of these models in the context of compact X-ray sources.

scholarly journals Critical Analysis of High Particle Number Emissions from Accelerating Compressed Natural Gas Buses

2010 ◽  
Vol 44 (10) ◽  
pp. 3724-3731 ◽  
Author(s):  
E. R. Jayaratne ◽  
N. K. Meyer ◽  
Z. D. Ristovski ◽  
L. Morawska ◽  
B. Miljevic
Keyword(s):  
Natural Gas ◽  
Critical Analysis ◽  
Particle Number ◽  
Compressed Natural Gas ◽  
High Particle

scholarly journals Investigations of nanoparticle emissions of two gasoline cars MPI & DI at stationary part load operation

2014 ◽  
Vol 158 (3) ◽  
pp. 3-11
Author(s):  
Jan CZERWIŃSKI ◽  
Pierre COMTE ◽  
Alejandro KELLER ◽  
Andreas MAYER
Keyword(s):  
Particle Size ◽  
Particle Number ◽  
Direct Injection ◽  
Ultrafine Particle ◽  
Size Distributions ◽  
Particle Count ◽  
Particle Size Fractions ◽  
High Particle ◽  
Injection Technology ◽  
20 Nm

Starting from Euro 6 not only for diesel but also for gasoline vehicles, with direct injection technology (GDI) a solid particle number emissions limit of 6 × 1011 #/km becomes effective. The limit was temporary extended for GDI to 6 x 1012 #/km. Nuclei of metals as well as organics are suspected to significantly contribute especially to the ultrafine particle size fractions, and thus to the particle number concentration. In the project GasOMeP (Gasoline Organic & Metal Particulates) metal-nanoparticles (including sub 20 nm) from gasoline cars are investigated for different engine technologies. In the present paper some results of basic investigations of nanoparticles from two gasoline cars – an older one with MPI and a never one with DI – are represented. The measurements were performed at vehicle tailpipe, with varying sampling conditions and with different SMPS-systems, which enabled the mobility scanning in different size ranges. The results show that the older vehicle with MPI emits high particle count concentrations. The size distributions are decisively bimodal with high numbers in nuclei mode. In this case, the particle counting below 10 nm yields important information. The emissions of the newer vehicle with DI show no typical uniform shape of particle size distributions and are at lower level, than for the older vehicle. There is no visible nuclei mode and the ultrafine particle concentrations below 10 nm are insignificant. A sampling with a strongly increased primary dilution has a clear influence on the indicated (higher) particle concentrations.

Chronic Laser Exposure Effects on Rabbit Retina

1972 ◽  
Vol 30 ◽  
pp. 54-55
Author(s):  
Burton B. Silver ◽  
Theodore Lawwill
Keyword(s):  
Laser Irradiation ◽  
Laser Light ◽  
Broad Band ◽  
Argon Laser ◽  
Atropine Sulfate ◽  
Ultrastructural Changes ◽  
Laser Exposure ◽  
Rabbit Retina ◽  
Histological Changes ◽  
Threshold Doses

Dutch-belted 1 to 2.5 kg anesthetized rabbits were exposed to either xenon or argon laser light administered in a broad band, designed to cover large areas of the retina. For laser exposure, the pupil was dilated with atropine sulfate 1% and pheny lephrine 10%. All of the laser generated power was within a band centered at 5145.0 Anstroms. Established threshold for 4 hour exposures to laser irradiation are in the order of 25-35 microwatts/cm2. Animals examined for ultrastructural changes received 4 hour threshold doses. These animals exhibited ERG, opthalmascopic, and histological changes consistent with threshold damage.One month following exposure the rabbits were killed with pentobarbitol. The eyes were immediately enucleated and dissected while bathed in 3% phosphate buffered gluteraldehyde.

Unbiased estimation of particle number and sizes using the new stereological tools: the disector, the fractionator, the selector, and the nucleator — or just point-sampled intercepts

1988 ◽  
Vol 46 ◽  
pp. 428-429
Author(s):  
H.J.G. Gundersen
Keyword(s):  
Particle Number ◽  
Small Distance ◽  
Parallel Plane ◽  
Unbiased Estimation ◽  
Severe Problem ◽  
New Era ◽  
Size And Shape ◽  
Distinct Property ◽  
Sectioned Tissue

Previously, all stereological estimation of particle number and sizes were based on models and notoriously gave biased results, were very inefficient to use and difficult to justify. For all references to old methods and a direct comparison with unbiased methods see recent reviews.The publication in 1984 of the DISECTOR, the first unbiased stereological probe for sampling and counting 3—D objects irrespective of their size and shape, signalled the new era in stereology — and give rise to a number of remarkably simple and efficient techniques based on its distinct property: It is the only known way to obtain an unbiased sample of 3-D objects (cells, organelles, etc). The principle is simple: within a 2-D unbiased frame count or sample only cells which are not hit by a parallel plane at a known, small distance h.The area of the frame and h must be known, which might sometimes in itself be a problem, albeit usually a small one. A more severe problem may arise because these constants are known at the scale of the fixed, embedded and sectioned tissue which is often shrunken considerably.

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