Francesca Migliorini

• PhD
• Researcher at Institute of Condensed Matter Chemistry and Technologies for Energy, Italian National Research Council

The effect of laser irradiation on carbon nanoparticles of different maturity sampled from a premixed flame is investigated. To this purpose, extinction and laser-induced incandescence measurements are carried out on pristine and pre-irradiated nanoparticles. From extinction measurements, a spectral trend of the absorption coefficient of the partic...

We develop a thermoelectric generator based on catalytic combustion and operating in the low power range (up to 10 W). Considering the target of small-scale thermoelectric generators, the additive technique was chosen as an enabling technology to customize the different parts of the presented device. The generator consists of a hexagonal shaped com...

The effect of rapid laser irradiation on the optical properties of mature soot particles is investigated by performing wavelength-resolved extinction measurements in the visible spectral region. In particular, the spectral behavior of the absorption properties is explored during laser irradiation, at the peak of the incandescence signal (prompt LII...

We develop a thermoelectric generator based on catalytic combustion and operating in the low power range (up to 10 W). Considering the target of small-scale thermoelectric generators, the additive technique was chosen as an enabling technology to customize the different parts of the presented device. The generator consists of a hexagonal shaped com...

In this work cooled carbon nanoparticles are investigated with the aim of gaining knowledge on their properties. To this purpose, a double pulse experiment is employed consisting essentially of a modified Laser-Induced Incandescence (LII) approach. Before the conventional LII measurements, nanoparticles are additionally irradiated applying differen...

In this work, light absorption spectra of carbon nanoparticles sampled at different heights from an ethylene/air premixed flame were studied. The spectral behavior of the light absorption coefficient was analyzed in the high energy (Tauc) and low energy (Urbach) regions. In the Tauc region, information on the optical band gap can be retrieved, whil...

Nanostructured cobalt oxide powders as electro catalysts for the oxygen evolution reaction (OER) in an alkaline membrane electrolysis cell (AME) were prepared by flame spray synthesis (FS); an AME’s anode was then produced by depositing the FS prepared cobalt oxide powders on an AISI-316 sintered metal fiber by the electrophoretic deposition (EPD)...

In this work, the optical absorption properties of carbon nanoparticles are investigated by applying in-flow extinction and laser-induced incandescence measurements. Carbon nanoparticles are produced in an ethylene/air premixed flame and sampled at different heights above the burner. From extinction measurements, the absorption coefficient is obtai...

Oxide nanoparticles are widely studied because of their unique properties, including their crystalline phase, surface area, and porosity, which make them attractive for several applications. These properties are related to the increase in the surface/volume ratio when moving from the bulk to the nanoscale. For this reason, a diagnostic tool capable...

The large use of portable devices imposes a new interest in the development of power backup systems with constraints in terms of compactness and safety. Such systems have to match the use as battery backups as well as a self-standing operating. Thermoelectric generators (TEGs) allow access to new ways of power supply thanks to their long lifetimes,...

In this work, a set of four partially premixed ethylene–air laminar flames, characterized by different equivalent ratios, was studied. The aim was to investigate the effect of partial premixing on soot formation, which is a relevant parameter for real combustion devices. Quantitative and qualitative information on soot particles were obtained using...

Chemiluminescence and laser-induced breakdown spectroscopy (LIBS) measurements have been carried out in laminar ethylene/air partially premixed flames for real-time local equivalence ratio monitoring. OH* and CH* chemiluminescence measurements have been performed in the region where combustion processes mainly occur. Using LIBS measurements, the hy...

In this work, laser-induced breakdown spectroscopy (LIBS) is applied for quantitative measurements of Pb in aerosols. In order to investigate the carrier gas role and, in particular, the effect of O2 addition to the gas itself, measurements are carried out in nitrogen and air atmosphere. Aerosol particles are produced by nebulizing Pb(CH3COO)2 * 3H...

Real-time monitoring of local equivalence ratio is of primary importance for chemical combustion efficiency improvement. In this context chemiluminescence and LIBS measurements have been presented and performed in premixed and diffusion flames. The ratio of radicals chemiluminescence emission is proved to be related to equivalence ratio in premixed...

Two-color laser-induced incandescence (LII) measurements are carried out in diffusion flames and at the exhaust of a homemade soot generator, both fueled with ethylene and methane. Two-color prompt LII signals, their ratio and the corresponding temperature have been analyzed as a function of laser fluence. In particular, the effect of fuel, soot lo...

The study of micropollutants formation and characterization has received particular attention by the research community for different aspects such as the global climate change, environmental pollution and the effects on human health. Air pollution is mainly due to exhaust gases from vehicles, heating systems, power plants, factories, incineration p...

Spectral, grey-scale and colour chemiluminescence measurements of C2* and CH* radicals' emission are carried out on the flame front of a methane─air premixed flame at different equivalence ratios. To this purpose, properly spatially resolved optical equipment has been implemented in order to reduce the background emission from other burned gas regi...

A portable instrument based on two-color laser-induced incandescence (LII) technique has been designed and developed for the detection of carbonaceous particles for environmental applications. The instrument has been calibrated by performing LII measurements at the exhaust of a home-made soot generator. The incandescence signal from particles sampl...

The effect of hydrogen addition to fuel in soot formation and growth mechanisms is investigated in a rich ethylene/air premixed flame. To this purpose, three-angle scattering and extinction measurements are carried out in flames with different hydrogen contents. By applying the Rayleigh–Debye–Gans theory and the fractal-like description, soot conce...

We report a new method for automated identification and measurement of primary particles within soot aggregates as well as the sizes of the aggregates and discuss its application to high-resolution transmission electron microscope (TEM) images of the aggregates. The image processing algorithm is based on an optimized Hough transform, applied to the...

The optical properties of soot, in particular the propensity of soot to absorb and scatter light as a function of wavelength, are key parameters for the correct interpretation of soot optical diagnostics. An overview of the data available in the literature highlights the differences in the reported optical properties of aging soot. In many cases, t...

Theoretical papers predict that prompt LII signals are weakly dependent on the soot size due to the fact that larger particles reach higher temperatures during the heating process by nanosecond laser pulses. This question is of crucial importance for establishing LII as a practical technique for soot volume fraction measurements. In this work two-c...

McKenna burners are widely used in the combustion community for producing “flat” premixed flames. These flames are considered as standards for the development and calibration of optical techniques. Rich premixed flames produced by McKenna burners are frequently investigated in order to understand soot formation processes both by optical and by samp...

The two-color laser-induced incandescence (2C-LII) technique can be used for soot volume fraction measurements with no use of a reference flame of known soot concentration. In this work we have exploited the 2C-LII technique with the development of a two-dimensional imaging arrangement. By utilizing an IR pulsed laser, a laser sheet with sharp edge...

A numerical iterative procedure is presented for the evaluation of the effect of signal absorption in two-color laser-induced incandescence measurements. The correction process is applied to our experimental data in an axisymmetric flame [Appl. Opt. 44, 7414 (2005)]. The influence of signal trapping on peak soot temperature and on soot volume fract...

In order to understand the processes involved in the laser-induced incandescence (LII) technique, the value of soot temperature at the peak of the incandescence signal has been studied. To this purpose, an absolute two-color LII technique has been applied on ethylene and methane diffusion flames, based on the comparison with a calibrated tungsten r...

In this work we extend the concepts of the well known two-color emission technique for the realization of a two-color LII arrangement in order to perform soot volume fraction measurements with no use of a reference soot measurements carried out in other ways. Maximum soot temperatures around 4050 K were measured for fluences in the range 300 – 600...

Improving fuel economy and reduction of exhaust emissions have become the major concerns in the combustion community. Due to low pollutant emission and superior combustion characteristics hydrogen/hydrocarbon blends have received increased attention as alternative fuels for numerous power generation applications. The combustion chemistry of hydroca...

The present work has been focused on combustion generated soot, small nanoparticles and large PAHs. The investigation has been performed on laminar premixed ethylene/H 2 /air flames by applying laser-induced incandescence and laser-induced fluorescence techniques. Experimental data have been compared with modeling results in order to clarify the ro...

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