The change of soot refractive index function along the height of premixed ethylene/air flame and its correlation with soot structure

2020 ◽  
Vol 126 (8) ◽  
Author(s):  
A. V. Eremin ◽  
E. V. Gurentsov ◽  
R. N. Kolotushkin
Keyword(s):  
Refractive Index ◽  
Index Function

scholarly journals A review on determining the refractive index function, thermal accommodation coefficient and evaporation temperature of light-absorbing nanoparticles suspended in the gas phase using the laser-induced incandescence

2018 ◽  
Vol 7 (6) ◽  
pp. 583-604 ◽  
Author(s):  
Evgeny Valerievich Gurentsov
Keyword(s):  
Refractive Index ◽  
Physical Properties ◽  
Laser Heating ◽  
Volume Fraction ◽  
Accommodation Coefficient ◽  
Nanosecond Laser ◽  
Index Function ◽  
Evaporation Temperature ◽  
Laser Induced Incandescence ◽  
Thermo Physical Properties

AbstractIn this review, the possibility of using pulsed, nanosecond laser heating of nanoparticles (NPs) is demonstrated, in order to investigate their thermo-physical properties. This approach is possible because the laser heating produces high NP temperatures that facilitate the observation of their thermal radiation (incandescence). This incandescence depends on the thermo-physical properties of the NPs, such as heat capacity, density, particle size, volume fraction and the refractive index of the particle material, as well as on the heat-mass transfer between the NPs and the surrounding gas media. Thus, the incandescence signal carries information about these properties, which can be extracted by signal analyses. This pulsed laser heating approach is referred to as laser-induced incandescence. Here, we apply this approach to investigate the properties of carbon, metal and carbon-encapsulated Fe NPs. In this review, the recent results of the measurements of the NP refractive index function, thermal energy accommodation coefficient of the NP surface with bath gas molecules and the NP evaporation temperature obtained using laser-induced incandescence are presented and discussed.

Size dependence of complex refractive index function of growing nanoparticles

2011 ◽  
Vol 104 (2) ◽  
pp. 285-295 ◽  
Author(s):  
A. Eremin ◽  
E. Gurentsov ◽  
E. Popova ◽  
K. Priemchenko
Keyword(s):  
Refractive Index ◽  
Size Dependence ◽  
Complex Refractive Index ◽  
Index Function

Optical Properties in the Visible of Overfire Soot in Large Buoyant Turbulent Diffusion Flames

2000 ◽  
Vol 122 (3) ◽  
pp. 517-524 ◽  
Author(s):  
S. S. Krishnan ◽  
K.-C. Lin ◽  
G. M. Faeth
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Turbulent Diffusion ◽  
Diffusion Flames ◽  
Complex Refractive Index ◽  
Mean Value ◽  
Index Function ◽  
Turbulent Diffusion Flames ◽  
Visible Wavelengths ◽  
Good Agreement

Nonintrusive measurements of the optical properties of soot at visible wavelengths (351.2–800.0 nm) were completed for soot in the overfire region of large (2–7 kW) buoyant turbulent diffusion flames burning in still air at standard temperature and pressure, where soot properties are independent of position and characteristic flame residence time for a particular fuel. Soot from flames fueled with gaseous (acetylene, ethylene, propylene, and butadiene) and liquid (benzene, cyclohexane, toluene, and n-heptane) hydrocarbon fuels were studied. Scattering and extinction measurements were interpreted to find soot optical properties using the Rayleigh-Debye-Gans/polydisperse-fractal-aggregate theory after establishing that this theory provided good predictions of scattering patterns over the present test range. Effects of fuel type on soot optical properties were comparable to experimental uncertainties. Dimensionless extinction coefficients were relatively independent of wavelength for wavelengths of 400–800 nm and yielded a mean value of 8.4 in good agreement with earlier measurements. Present measurements of the refractive index function for absorption, Em, were in good agreement with earlier independent measurements of Dalzell and Sarofim and Stagg and Charalampopoulos. Present values of the refractive index function for scattering, Fm, however, only agreed with these earlier measurements for wavelengths of 400–550 nm but otherwise increased with increasing wavelength more rapidly than the rest. The comparison between present and earlier measurements of the real and imaginary parts of the complex refractive index was similar to Em and Fm.[S0022-1481(00)02203-9]

Modeling TiO2׳s refractive index function from bulk to nanoparticles

2015 ◽  
Vol 167 ◽  
pp. 105-118 ◽  
Author(s):  
Juho-Pertti Jalava ◽  
Veli-Matti Taavitsainen ◽  
Ralf-Johan Lamminmäki ◽  
Minna Lindholm ◽  
Sami Auvinen ◽  
...  
Keyword(s):  
Refractive Index ◽  
Index Function

scholarly journals Characteristics of Cμ2 derived from ultrasonic anemometer in an urban boundary layer

2019 ◽  
Vol 28 (1) ◽  
pp. 14-24
Author(s):  
Monim Al-Jiboori ◽  
Sundus Jaber
Keyword(s):  
Refractive Index ◽  
Atmospheric Stability ◽  
Ground Level ◽  
Fast Response ◽  
Turbulent Medium ◽  
Optical Wave ◽  
Index Function ◽  
Function Coefficient ◽  
Stable Conditions ◽  
Ultrasonic Anemometer

Fast-response observations of three components of wind and air temperature have been applied to calculate the refractive index function coefficient (Cμ2 ), which is needed to describe optical wave propagation in a turbulent medium. These were measured by 3D ultrasonic anemometer installed on the roof of the building of Atmospheric Science Department which is 19 m above ground level. Refractive index function coeffi cient was calculated for various periods of three seasons: winter, spring and summer.Diurnal variations of (Cμ2) have been made at the surface layer for these seasons. The results show that high values ofmean (Cμ2) occurred during the day time more than at night, also they occurred more in summer than in winter and spring. The results of (Cμ2) found to change with atmospheric stability, whereas they inversely decrease under unstable conditions, approximately constant at neutral cases, and increase under stable conditions. Values of (Cμ2) on average appears to be lower during the rainy and foggy weather cases compared to those of clear sky.

Evolution of the optical band gap in Titanium-based Oxy-(Hydroxy)-Fluorides series

2005 ◽  
Vol 891 ◽  
Author(s):  
Nicolas Penin ◽  
Nicolas Viadere ◽  
Damien Dambournet ◽  
Alain Tressaud ◽  
Alain Demourgues
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Electronic Structures ◽  
Optical Band Gap ◽  
Inorganic Compounds ◽  
Structural Features ◽  
Chemical Compositions ◽  
Index Function ◽  
Cationic Substitution ◽  
The One

ABSTRACTThe optical band gap related to the electronic structures as well as the refractive index function of the electronic polarizability of the network can be tailored by changing the nature and the number of anions into the vicinity of cations. New routes have been developed in order to prepare new divided Ti(IV)-based oxyfluorinated compounds. In these compounds, the optical absorptions appear at the UV-Vis frontier and the refractive index is always smaller than the one of equivalent oxides. The chemical bonding, the hybridation and the density of the network play key roles in the variation of the optical band gap and the refractive index. For this family of titanium-based oxyfluorides containing mixed anions, chemical compositions and structural features have been correlated to the optical band gap and the refractive index, i.e. the complex index of materials n(λ) + ik(λ). Several examples will be given in order to illustrate the potentialities of these new inorganic compounds by changing the F/Ti ratio and the cationic substitution.

Determination of the ratio of soot refractive index function E(m) at the two wavelengths 532 and 1064 nm by laser induced incandescence

2007 ◽  
Vol 89 (2-3) ◽  
pp. 417-427 ◽  
Author(s):  
E. Therssen ◽  
Y. Bouvier ◽  
C. Schoemaecker-Moreau ◽  
X. Mercier ◽  
P. Desgroux ◽  
...  
Keyword(s):  
Refractive Index ◽  
Index Function ◽  
Laser Induced Incandescence

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

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