Soot and nanoparticle formation in laminar and turbulent flames

Commodo, M.
Violi, S.
D'Anna, A.
D'Alessio, A.
Allouis, Christophe Gerard
Beretta, F.
Minutolo, P.
A new optical diagnostic method has been developed based on the interaction of a pulsed UV laser source with combustion-generated aerosols. This method allows characterization of nanoparticles of organic carbon (NOC) and soot by point measurements. Fluorescence and incandescence measurements induced by the fifth harmonic of a Nd-YAG laser at 213 nm are used for the determination of the volume fractions of particulates in a laminar premixed flame and in a turbulent non-premixed flame of ethylene/air. The selected light source enhances the fluorescence of NOC, which exhibit a large absorption band between 200 and 250 nm and also heats up soot particles to give incandescent emission. Ultraviolet emission signals are correlated with NOC extinction coefficients, while LII signals are correlated with extinction coefficients in the visible region. Laser light scattering measurements are used to estimate the mean sizes of both classes of particles.


3D-graphene-laser patterned p-type silicon Schottky diode
Orhan, Elif Oz; Efil, Esra; Bayram, Ozkan; Kaymak, Nuriye; Berberoğlu, Halil; Candemir, Ozun; Pavlov, Ihor; Ocak, Sema Bilge (Elsevier BV, 2021-01-01)
© 2020 Elsevier LtdThe influence of the laser patterning (LP) process on the quality of graphene (Gr) film and Schottky diode characteristics was researched in this study. First of all, p-type silicon (Si) was patterned by homemade femtosecond laser source. To compare the resulting effect, non-patterned n-Si and p-Si were used as substrates. To achieve vertically oriented three-dimensional (3D) Gr nanosheets (VGNs) onto the laser patterned p-type Si, non-patterned n-Si, and p-Si substrates, we used Radio-Fr...
Ultralow Threshold One-Photon- and Two-Photon-Pumped Optical Gain Media of Blue-Emitting Colloidal Quantum Dot Films
Guzelturk, Burak; Keleştemur, Yusuf; Akgul, Mehmet Zafer; Sharma, Vijay Kumar; Demir, Hilmi Volkan (2014-07-01)
Colloidal quantum dots (QDs) offer advantageous properties as an optical gain media for lasers. Optical gain in the QDs has been shown in the whole visible spectrum, yet it has been intrinsically challenging to realize efficient amplified spontaneous emission (ASE) and lasing in the blue region of the visible spectrum. Here, we synthesize large-sized core/gradient shell CdZnS/ZnS QDs as an efficient optical gain media in the blue spectral range. In this Letter, we demonstrate for the first time that two-pho...
Thin Lens Narcissus Model in Infrared Lens Design with Cooled Detectors
Aslan, Serhat; Yerli, Sinan Kaan (2022-01-01)
A mathematical model of the narcissus effect in infrared lenses with cooled detectors is discussed. The proposed model enables optical designers to take the narcissus performance of infrared lenses into consideration in the thin lens predesign stage. Third order thin lens aberration theory is the basis for the newly proposed narcissus analysis. Two narcissus metrics are defined in terms of structural parameters of the infrared lens to be designed. The metrics provide an indirect way of controlling narcissus...
Magnetohydrodynamic flow imaging of ionic solutions using electrical current injection and MR phase measurements
Eroglu, Hasan H.; Sadighi, Mehdi; Eyüboğlu, Behçet Murat (Elsevier BV, 2019-06-01)
In this study, a method is proposed to image magnetohydrodynamic (MHD) flow of ionic solutions, which is caused by externally injected electrical current to an imaging media, during MRI scans. A multi-physics (MP) model is created by using the electrical current, laminar flow, and MR equations. The conventional spoiled gradient echo MRI pulse sequence with bipolar flow encoding gradients is utilized to encode the MHD flow. Using the MP model and the MRI pulse sequence, relationship between the MHD flow rela...
Nano-scale phase separation and glass forming ability of iron-boron based metallic glasses
Aykol, Muratahan; Akdeniz, Mahmut Vedat; Department of Metallurgical and Materials Engineering (2008)
This study is pertinent to setting a connection between glass forming ability (GFA) and topology of Fe-B based metallic glasses by combining intimate investigations on spatial atomic arrangements conducted via solid computer simulations with experimentations on high GFA bulk metallic glasses. In order to construct a theoretical framework, the nano-scale phase separation encountered in metallic glasses is investigated for amorphous Fe80B20 and Fe83B17 alloys via Monte Carlo equilibration and reverse Monte Ca...
Citation Formats
M. Commodo et al., “Soot and nanoparticle formation in laminar and turbulent flames,” COMBUSTION SCIENCE AND TECHNOLOGY, pp. 387–400, 2007, Accessed: 00, 2021. [Online]. Available: