Rapid Identification of High Particle Number Emitting On-Road Vehicles and Its Application to a Large Fleet of Diesel Buses

2007 ◽  
Vol 41 (14) ◽  
pp. 5022-5027 ◽  
Author(s):  
E. R. Jayaratne ◽  
L. Morawska ◽  
Z. D. Ristovski ◽  
C. He
Keyword(s):  
Particle Number ◽  
Rapid Identification ◽  
Road Vehicles ◽  
High Particle ◽  
Diesel Buses

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.

Sub-23nm exhaust particle number emissions from latest Euro 6 passenger road vehicles

2020 ◽  
Author(s):  
Zisimos Toumasatos ◽  
Andersson Jonathan ◽  
Leonidas Ntziachristos ◽  
Mamakos Athanasios ◽  
Klug Andreas ◽  
...  
Keyword(s):  
Particle Number ◽  
Road Vehicles

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 DPF retrofit program in Israel – effects of diesel particle filters on performance of in-use buses

2017 ◽  
Vol 170 (3) ◽  
pp. 176-178
Author(s):  
Leonid TARTAKOVSKY ◽  
Rafael FLEISCHMAN
Keyword(s):  
Engine Performance ◽  
Cost Effective ◽  
Pilot Project ◽  
Economic Incentives ◽  
Particulate Emissions ◽  
Heavy Duty ◽  
Effective Measure ◽  
High Particle ◽  
Diesel Buses ◽  
Heavy Duty Diesel

A long service life of heavy-duty diesel vehicles results in a large number of older-technology trucks and buses of various types running on roads nowadays. Cleaning up exhaust gases of these older vehicles gives an opportunity to improve air quality at affordable costs. Retrofitting older buses with diesel particulate filters (DPF) is a cost-effective measure to quickly and efficiently reduce particulate matter (PM) emissions and contribute to mitigation of air pollution in urban conglomerates. In this paper, the milestones on a way to wide-scale retrofitting of heavy-duty vehicles with DPF are discussed on the example of Israel DPF retrofit program. Crucial importance of a balanced governmental approach combining regulation and economic incentives, together with collaboration of government, academia and vehicle operators, is underlined. Main results of the one-year pilot project focused on urban and intercity buses are discussed. Impact of DPF retrofitting on particulate emissions and engine performance and maintenance aspects of in-use diesel buses is analyzed. Very high particle filtration efficiency (in average, about 97%) together with relatively low fuel economy penalty (0.6–1.8%, depending on the bus type) are proved. Vital importance of careful monitoring and correct maintenance of DPF-equipped vehicles is underlined.

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.

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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