Characterization of Particulate From Fires Burning Silicone Fluids

2000 ◽  
Vol 123 (6) ◽  
pp. 1093-1097 ◽  
Author(s):  
Yudaya Sivathanu ◽  
Anthony Hamins ◽  
George Mulholland ◽  
Takashi Kashiwagi ◽  
Robert Buch
Keyword(s):  
Hydrocarbon Flame ◽  
Burner Surface ◽  
Hydrocarbon Flames ◽  
Volume Fractions ◽  
Multi Wavelength ◽  
Wavelength Absorption ◽  
Gravimetric Sampling ◽  
Dominant Part ◽  
Particulate Volume

The optical properties of particulate emitted from fires burning two distinct polydimethylsiloxane fluids (D4 and M2 or MM, where D=CH32SiO and M=CH33SiO2) were obtained using a transmission cell-reciprocal nephelometer in conjunction with gravimetric sampling. The specific absorption coefficient of particulate ash from fires burning D4 and MM is significantly lower than that of particulate soot from an acetylene (hydrocarbon) flame. Scattering is the dominant part of extinction in fires burning the silicone fluids. This is very different from extinction by soot particles in hydrocarbon fires, where absorption is approximately five times greater than scattering. Temperatures and particulate volume fractions along the axis of a silicone fire D4 were measured using multi-wavelength absorption/emission spectroscopy. The structure of the D4 flames is markedly different from hydrocarbon flames. The temperatures and particulate volume fractions very close to the burner surface are much higher than in comparably sized hydrocarbon flames.

scholarly journals Revealing soot maturity based on multi-wavelength absorption/emission measurements in laminar axisymmetric coflow ethylene diffusion flames

2021 ◽  
Vol 227 ◽  
pp. 147-161
Author(s):  
Jérôme Yon ◽  
Juan José Cruz ◽  
Felipe Escudero ◽  
José Morán ◽  
Fengshan Liu ◽  
...  
Keyword(s):  
Diffusion Flames ◽  
Multi Wavelength ◽  
Wavelength Absorption

scholarly journals The characterization of Taklamakan dust properties using a multi-wavelength Raman polarization lidar in Kashi, China

2020 ◽  
Author(s):  
Qiaoyun Hu ◽  
Haofei Wang ◽  
Philippe Goloub ◽  
Zhengqiang Li ◽  
Igor Veselovskii ◽  
...  
Keyword(s):  
Fine Particles ◽  
Depolarization Ratio ◽  
Taklamakan Desert ◽  
Multi Wavelength ◽  
Lidar Ratio ◽  
Linear Depolarization Ratio ◽  
Dust Events ◽  
532 Nm ◽  
Depolarization Ratios

Abstract. The Taklamakan desert is an important dust source for the global atmospheric dust budget and a cause of the dust weather in Eastern Asia. The characterization of the properties and vertical distributions of Taklamakan dust in the source region is still very limited. To fill this gap, the DAO (Dust Aerosol Observation) was conducted in Kashi, China in 2019. Kashi site is about 150 km to the west rim of the Taklamakan desert and is strongly impacted by desert dust aerosols, especially in spring time, i.e. April and May. Apart from dust, fine particles coming from local anthropogenic emissions or/and transported aerosols are also a non-negligible aerosol component. In this study, we provide the first profiling of the 2α + 3β + 3δ lidar profiles of Taklamakan dust based on a multi-wavelength Raman polarization lidar. Four cases, including two Taklamakan dust events (Case 1 and 2) and two polluted dust events (Case 3 and 4) are presented. The lidar ratio in the Taklamakan dust outbreak is found to be 51 ± 8–56 ± 8 sr at 355 nm and 45 ± 7 sr at 532 nm. The particle linear depolarization ratios are about 0.28 ± 0.04–0.32 ± 0.05 at 355 nm, 0.35 ± 0.05 at 532 nm and 0.31 ± 0.05 at 1064 nm. The observed polluted dust is commonly featured with reduced particle linear depolarization ratio and enhanced extinction and backscatter Angstrom exponent. In Case 3, the lidar ratio of polluted dust is about 42 ± 6 sr at 355 nm and 40 ± 6 sr at 532 nm. The particles linear depolarization ratios decrease to about 0.25, with a weak spectral dependence. In Case 4, the variability of lidar ratio and particle linear depolarization ratio is higher than in Case 3, which reflects the complexity of the nature of mixed pollutant and the mixing state. The results provide the first reference for the characteristics of Taklamakan dust measured by Raman lidar. The data could contribute to complementing the dust model and improving the accuracy of climate modeling.

Prospects for a Multi-Wavelength Characterization of Cepheid Envelopes

2009 ◽  
Vol 38 ◽  
pp. 143-149
Author(s):  
P. Kervella ◽  
A. Mérand
Keyword(s):  
Multi Wavelength

ACTRIS efforts for Sentinel 5 Precursor validation

2020 ◽  
Author(s):  
Lucia Mona ◽  
Nikolaos Papagiannopoulus ◽  
Gelsomina Pappalardo ◽  
Ulla Wandinger ◽  
Giuseppe D'Amico ◽  
...  
Keyword(s):  
State Of The Art ◽  
Aerosol Layer ◽  
Additional Information ◽  
Cloud Radar ◽  
Vertical Profiling ◽  
First Results ◽  
Multi Wavelength ◽  
Spatio Temporal ◽  
Aerosol Type

<p>The Sentinel 5 Precursor products, call for an accurate validation. Europe can be nowadays regarded as a leader in ground-based vertical profiling observations. ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) is an EC funded infrastructure integrating European ground-based stations equipped with advanced atmospheric equipment. Among these, EARLINET (European Aerosol Research Lidar NETwork) and Cloudnet are well-established networks providing vertical profiles of aerosol and clouds with high vertical and temporal resolution. A network of ground-based stations has the ability to provide the spatio-temporal development of aerosol and cloud fields and offers a unique opportunity for the validation of observations from space. In this project, state-of-the-art instrumentations for observing aerosol and clouds will be used for validation purposes: multi-wavelength lidar (EARLINET) and Doppler cloud radar (Cloudnet).</p><p>Characterization of aerosol and cloud fields over the stations is provided by the use of EARLINET and Cloudnet data. Additional information is provided by AERONET data where available. Differences will be reported as a function of aerosol load, aerosol and cloud height, aerosol type, cloud type and underneath surface.</p><p>First results of validation efforts performed within ACTRIS in terms of a quantitative evaluation of the accuracy of S5P aerosol and cloud products will be reported. This activity is done under the EC-ACTS: Earlinet and Cloudnet - Aerosol and Clouds Teams for Sentinel-5P Validation unfunded project, which comprises 3 EARLINET/Cloudnet stations [Potenza (IT), Leipzig (DE) and Cabauw (NL)]; 3 EARLINET stations [Granada (ES), Athens (GR) and Bucharest (RO)] and 2 Cloudnet sites [Mace Head (IE) and Sodankylä (FI)].</p><p>In particular, the first results will be about the S5P Aerosol Layer Height (mandatory product) and Aerosol Optical Depth (optional product) and whenever available the AAI-based columnar Aerosol Type product.</p>

scholarly journals Comparison of different Aethalometer correction schemes and a reference multi-wavelength absorption technique for ambient aerosol data

2017 ◽  
Vol 10 (8) ◽  
pp. 2837-2850 ◽  
Author(s):  
Jorge Saturno ◽  
Christopher Pöhlker ◽  
Dario Massabò ◽  
Joel Brito ◽  
Samara Carbone ◽  
...  
Keyword(s):  
Wavelength Dependence ◽  
Absorption Coefficients ◽  
Multiple Wavelength ◽  
Filter Loading ◽  
Multi Wavelength ◽  
Online Measurements ◽  
Loading Effects ◽  
Wavelength Absorption ◽  
Absorption Photometer ◽  
Absorption Measurements

Abstract. Deriving absorption coefficients from Aethalometer attenuation data requires different corrections to compensate for artifacts related to filter-loading effects, scattering by filter fibers, and scattering by aerosol particles. In this study, two different correction schemes were applied to seven-wavelength Aethalometer data, using multi-angle absorption photometer (MAAP) data as a reference absorption measurement at 637 nm. The compensation algorithms were compared to five-wavelength offline absorption measurements obtained with a multi-wavelength absorbance analyzer (MWAA), which serves as a multiple-wavelength reference measurement. The online measurements took place in the Amazon rainforest, from the wet-to-dry transition season to the dry season (June–September 2014). The mean absorption coefficient (at 637 nm) during this period was 1.8 ± 2.1 Mm−1, with a maximum of 15.9 Mm−1. Under these conditions, the filter-loading compensation was negligible. One of the correction schemes was found to artificially increase the short-wavelength absorption coefficients. It was found that accounting for the aerosol optical properties in the scattering compensation significantly affects the absorption Ångström exponent (åABS) retrievals. Proper Aethalometer data compensation schemes are crucial to retrieve the correct åABS, which is commonly implemented in brown carbon contribution calculations. Additionally, we found that the wavelength dependence of uncompensated Aethalometer attenuation data significantly correlates with the åABS retrieved from offline MWAA measurements.

Evaluation of Very High Resolution Multi-Wavelength Raman Spectroscopy for In-Line Characterization of Patterned Epitaxial Si1-xGex Layers on Si(100) Wafers

2019 ◽  
Vol 35 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Victor Vartanian ◽  
Takeshi Ueda ◽  
Toshikazu Ishigaki ◽  
Kitaek Kang ◽  
Woo Sik Yoo
Keyword(s):  
Raman Spectroscopy ◽  
High Resolution ◽  
Multi Wavelength ◽  
Very High
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