Michela Alfè - Academia.edu (original) (raw)

Papers by Michela Alfè

Research paper thumbnail of Measurements and Modeling of Carbon and Hydrocarbon Species Evolution at Soot Inception in Premixed Flames

Research paper thumbnail of Aromatic structures of carbonaceous materials and soot inferred by spectroscopic analysis

Carbon, 2004

UV-visible spectroscopy provides an extremely powerful methodology to investigate molecular struc... more UV-visible spectroscopy provides an extremely powerful methodology to investigate molecular structures of high molecular weight aromatic materials, not amenable to be characterized by analytical techniques as gas-chromatography, mass spectrometry, etc. However, the interpretation of UV-visible spectroscopic data relative to complex mixtures is extremely difficult and, when the technique is applied to solid samples, could lead to questionable results.

Research paper thumbnail of Aggregation and interactions of C60 and C70 fullerenes in neat N-methylpyrrolidinone and in N-methylpyrrolidinone/toluene mixtures

Chemical Physics Letters, 2005

... References. [1] B. Apicella, A. Ciajolo, R. Barbella, A. Tregrossi, TJ Morgan, AA Herod and R... more ... References. [1] B. Apicella, A. Ciajolo, R. Barbella, A. Tregrossi, TJ Morgan, AA Herod and R. Kandiyoti, Energy Fuels 17 (2003) (3), p. 565. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (11). [2] AA Herod ...

Research paper thumbnail of The effect of temperature on soot properties in premixed methane flames

Combustion and Flame, 2010

The effect of flame temperature on soot properties was studied in premixed methane/oxygen flames ... more The effect of flame temperature on soot properties was studied in premixed methane/oxygen flames burning at a constant mixture composition (C/O = 0.60, U = 2.4) and different cold-gas flow velocities (4 and 5 cm s À1 ). Temperature and concentration profiles of stable gases and condensed phases combustion products were measured along the flame axis. It was found that the high flame temperature conditions cause a larger decomposition of methane into hydrogen and C 2 -C 4 hydrocarbons, thereby reducing the formation of benzene and condensed phases including condensed species and soot. Soot properties were studied by UV-Visible absorption spectroscopy, thermogravimetry and H/C elemental analysis. A description of soot nanostructural organization was also performed by means of high-resolution transmission electron microscopy. Different properties and nanostructures were found to develop in the soot, depending on the temperature and on soot aging associated. Soot dehydrogenation occurred to a larger extent in the high flame temperature conditions. As soot dehydrogenates the mass absorption coefficients of soot exhibited an increasing trend along the flame axis. However, mature soot retained a relatively high H/C ratio and low absorption coefficients with respect to other less hydrogenated fuels even in high temperature conditions. This indicates that the aromatization/dehydrogenation of soot in premixed flames is more dependent on the fuel characteristics rather than on the flame temperature.

Research paper thumbnail of Advantages and Shortcomings of Mass Spectrometric Techniques for the Analysis of Aromatic Compounds Relevant in Combustion

Research paper thumbnail of Distribution of Soot Molecular Weight/Size along Premixed Flames as Inferred by Size Exclusion Chromatography

Energy & Fuels, 2007

The evolution of size/molecular weight (MW) of soot from inception to mature soot was studied by ... more The evolution of size/molecular weight (MW) of soot from inception to mature soot was studied by means of size exclusion chromatography (SEC) coupled with on-line UV-visible spectroscopy of soot sampled along the flame axis of ethylene, hexane, and benzene premixed flames. Polystyrene calibration and microfiltration were used for the evaluation of the soot MW and size, respectively. Overall, soot exhibited a wide MW/size distribution peaking in two main regions, well detached from each other. The first corresponds with particles/ aggregates having MW > 20 000 u, here called the "particle-size region", and the second one corresponds with molecules in the 100-5000 u MW range called the "molecular-size region". The components in the particle-size regions dominated, particularly downstream of the flames and everywhere in the benzene flame. Two classes of components were evident in the particle-size region: one with d > 20 nm (MW > 59 500 u) and the second class well below 20 nm discriminated by SEC, coupled with microfiltration. Meaningful differences in the relative contributions of these two classes were found to occur along the flames, affected by the fuel aromaticity, and they were signatures of the soot growth process and of the different soot inception mechanisms in aliphatic and benzene flames respectively.

Research paper thumbnail of Advantages and limitations of laser desorption/ionization mass spectrometric techniques in the chemical characterization of complex carbonaceous materials

International Journal of Mass Spectrometry, 2010

Laser desorption/ionization techniques coupled with mass spectrometry analyzers have evolved rapi... more Laser desorption/ionization techniques coupled with mass spectrometry analyzers have evolved rapidly in the recent years and are currently capable of providing valuable information about the chemical composition and structure of very high molecular weight species, mainly biopolymers or synthetic polymers.

Research paper thumbnail of Similarities and dissimilarities in n-hexane and benzene sooting premixed flames

Proceedings of the Combustion Institute, 2007

The flame structure of atmospheric-pressure sooting premixed flames of aliphatic and aromatic hyd... more The flame structure of atmospheric-pressure sooting premixed flames of aliphatic and aromatic hydrocarbons with the same carbon atom number (hexane and benzene) were studied at similar temperatures and C/O ratios by sampling and chemical and spectroscopic analysis. The differences in the oxidation mechanism of hexane and benzene in fuel-rich conditions were found to produce a different chemical environment in the

Research paper thumbnail of Mass spectrometric analysis of large PAH in a fuel-rich ethylene flame

Proceedings of the Combustion Institute, 2007

Research paper thumbnail of Effect of fuel/air ratio and aromaticity on the molecular weight distribution of soot in premixed n-heptane flames

Proceedings of the Combustion Institute, 2009

Research paper thumbnail of Structure–property relationship in nanostructures of young and mature soot in premixed flames

Proceedings of the Combustion Institute, 2009

A structural description of young and mature soot sampled from methane, ethylene, cyclohexane and... more A structural description of young and mature soot sampled from methane, ethylene, cyclohexane and benzene premixed flames, burning in fuel-rich conditions, was performed by means of high-resolution transmission electron microscopy (HRTEM). HRTEM image analysis was carried out to achieve semiquantitative information about the soot organization. Different nanostructures were found to develop in the soot, depending on the fuel and on soot aging.

Research paper thumbnail of Vibrationally resolved high-resolution NEXAFS and XPS spectra of phenanthrene and coronene

The Journal of chemical physics, Jan 28, 2014

We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption ... more We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption Fine-Structure (NEXAFS) spectroscopy and X-ray Photoelectron Spectroscopy in the gas phase of two polycyclic aromatic hydrocarbons (phenanthrene and coronene), typically formed in combustion reactions. In the NEXAFS of both molecules, a double-peak structure appears in the C1s → LUMO region, which differ by less than 1 eV in transition energies. The vibronic coupling is found to play an important role in such systems. It leads to weakening of the lower-energy peak and strengthening of the higher-energy one because the 0 - n (n > 0) vibrational progressions of the lower-energy peak appear in nearly the same region of the higher-energy peak. Vibrationally resolved theoretical spectra computed within the Frank-Condon (FC) approximation and linear coupling model agree well with the high-resolution experimental results. We find that FC-active normal modes all correspond to in-plane vibrati...

Research paper thumbnail of Characterization of carbon particulate matter relevant in combustion

Research paper thumbnail of Size/molecular weight distribution in the nucleation mode of flame-generated soot

Research paper thumbnail of Soot nanostructure evolution in premixed flames by High Resolution Electron Transmission Microscopy (HRTEM)

Proceedings of the Combustion Institute, 2015

ABSTRACT HRTEM fringe analysis by means of our “Analyse Plan” (AP) tool and a new HRTEM image ana... more ABSTRACT HRTEM fringe analysis by means of our “Analyse Plan” (AP) tool and a new HRTEM image analysis procedure, based on mathematical morphological analysis (MA), was applied to soot sampled along the axis of sooting premixed benzene and ethylene flames. The layer length obtained by means of MA approach was found to be higher in respect to the layer length derived from AP method, as it better accounts for their local curvature and distortion. The mean layer length obtained by the MA method was then proved to agree well with the data evaluated by Raman spectroscopy. Moreover, the MA method was useful for extracting other soot nanostructural parameters related to the geometry of individual fringes as layer length, tortuosity, and local curvature radii, in turn correlated with the defective nature of soot structure. Some parameters provided by the MA method appeared to be more sensitive and informative about structural changes occurring as soot is formed. In particular, the percentage of fringes with high tortuosity and the percentage of nearly-straight fragments were found to decrease and increase, respectively, throughout the soot formation region. These trends suggested a better stacking of longer and more planar layers testifying the structural order improvement with soot aging. It was also observed that the soot nanostructural ordering occurred faster for benzene with respect to ethylene soot in agreement with H/C and absorption coefficients trends. The distributions of carbon in differently-sized aromatic structures were evaluated on the basis of the fringe length distribution to follow the aromatic growth. The method assigned aromatic sizes to the extracted HRTEM fringes, assuming that the fringes are in the shape of parallelograms. The distributions were found to evolve toward larger size aromatic systems demonstrating the occurrence of aromatic growth during soot formation.

Research paper thumbnail of Characterization of nanometric carbon materials by time-resolved fluorescence polarization anisotropy

Optics and Lasers in Engineering, 2006

Research paper thumbnail of Mass spectrometric analysis of large PAH in a fuel-rich ethylene flame

Proceedings of the Combustion Institute, 2007

Mass spectrometric analysis by laser desorption-time of flight-mass spectrometry (LDI-TOF-MS) was... more Mass spectrometric analysis by laser desorption-time of flight-mass spectrometry (LDI-TOF-MS) was exploited to extend the detection of flame-formed polycyclic aromatic hydrocarbons (PAH) up to the mass limit of the first soot particles (>2000 Da) in the soot formation region of a premixed fuel-rich (C/O = 1) ethylene flame. The typical decreasing intensity of PAH ion peaks with increasing mass was found in the mass range m/z 500-1700 although a slight enrichment in the heavier part of PAH could be observed to occur along the flame axis. The separation by means of size exclusion chromatography (SEC) into two different classes of PAH followed by UV-visible spectroscopy corroborated the mass spectral identification of large mass PAH. Critical examination of mass spectral features and SEC separation was the starting point for speculation about the changes occurring in PAH growth from planar to concave structures which could be important for soot inception mechanisms.

Research paper thumbnail of Analysis of the Impact of the Dual-Fuel Ethanol-Diesel System on the Size, Morphology, and Chemical Characteristics of the Soot Particles Emitted from a LD Diesel Engine

SAE Technical Paper Series, 2014

Research paper thumbnail of Diesel exhaust particle exposure in vitro impacts T lymphocyte phenotype and function

Particle and Fibre Toxicology, 2014

Background: Diesel exhaust particles (DEP) are major constituents of ambient air pollution and th... more Background: Diesel exhaust particles (DEP) are major constituents of ambient air pollution and their adverse health effect is an area of intensive investigations. With respect to the immune system, DEP have attracted significant research attention as a factor that could influence allergic diseases interfering with cytokine production and chemokine expression. With this exception, scant data are available on the impact of DEP on lymphocyte homeostasis. Here, the effects of nanoparticles from Euro 4 (E4) and Euro 5 (E5) light duty diesel engines on the phenotype and function of T lymphocytes from healthy donors were evaluated. Methods: T lymphocytes were isolated from peripheral blood obtained from healthy volunteers and subsequently stimulated with different concentration (from 0.15 to 60 μg/ml) and at different time points (from 24 h to 9 days) of either E4 or E5 particles. Immunological parameters, including apoptosis, autophagy, proliferation levels, mitochondrial function, expression of activation markers and cytokine production were evaluated by cellular and molecular analyses.

Research paper thumbnail of Chemico-physical features of soot emitted from a dual-fuel ethanol–diesel system

ABSTRACT The paper describes an experimental study aimed to characterize the impact of the dual-f... more ABSTRACT The paper describes an experimental study aimed to characterize the impact of the dual-fuel ethanol–diesel combustion system on size, number and chemical characteristics of the emitted carbonaceous particles. The tests were conducted on a single cylinder research engine provided with a modern architecture and properly modified in a dual-fuel (DF) configuration. In particular, the experimental campaign was aimed to evaluate in detail the effect of the use of the ethanol as port injected fuel in diesel engine on the size distribution function, morphology, reactivity and chemical features of the exhaust emitted soot particles. The engine tests were chosen properly in order to represent actual working conditions of an automotive light-duty diesel engine. The morphological and chemical features of soot particles were studied in dependence of the ethanol–diesel substitution rate by analyzing the soot collected at the engine exhaust. Results indicated a significant effect of ethanol fumigation on the concentration of the emitted particles but not on the average size, as well as, a negligible impact of ethanol premixed charge on the soot nanostructural features.

Research paper thumbnail of Measurements and Modeling of Carbon and Hydrocarbon Species Evolution at Soot Inception in Premixed Flames

Research paper thumbnail of Aromatic structures of carbonaceous materials and soot inferred by spectroscopic analysis

Carbon, 2004

UV-visible spectroscopy provides an extremely powerful methodology to investigate molecular struc... more UV-visible spectroscopy provides an extremely powerful methodology to investigate molecular structures of high molecular weight aromatic materials, not amenable to be characterized by analytical techniques as gas-chromatography, mass spectrometry, etc. However, the interpretation of UV-visible spectroscopic data relative to complex mixtures is extremely difficult and, when the technique is applied to solid samples, could lead to questionable results.

Research paper thumbnail of Aggregation and interactions of C60 and C70 fullerenes in neat N-methylpyrrolidinone and in N-methylpyrrolidinone/toluene mixtures

Chemical Physics Letters, 2005

... References. [1] B. Apicella, A. Ciajolo, R. Barbella, A. Tregrossi, TJ Morgan, AA Herod and R... more ... References. [1] B. Apicella, A. Ciajolo, R. Barbella, A. Tregrossi, TJ Morgan, AA Herod and R. Kandiyoti, Energy Fuels 17 (2003) (3), p. 565. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (11). [2] AA Herod ...

Research paper thumbnail of The effect of temperature on soot properties in premixed methane flames

Combustion and Flame, 2010

The effect of flame temperature on soot properties was studied in premixed methane/oxygen flames ... more The effect of flame temperature on soot properties was studied in premixed methane/oxygen flames burning at a constant mixture composition (C/O = 0.60, U = 2.4) and different cold-gas flow velocities (4 and 5 cm s À1 ). Temperature and concentration profiles of stable gases and condensed phases combustion products were measured along the flame axis. It was found that the high flame temperature conditions cause a larger decomposition of methane into hydrogen and C 2 -C 4 hydrocarbons, thereby reducing the formation of benzene and condensed phases including condensed species and soot. Soot properties were studied by UV-Visible absorption spectroscopy, thermogravimetry and H/C elemental analysis. A description of soot nanostructural organization was also performed by means of high-resolution transmission electron microscopy. Different properties and nanostructures were found to develop in the soot, depending on the temperature and on soot aging associated. Soot dehydrogenation occurred to a larger extent in the high flame temperature conditions. As soot dehydrogenates the mass absorption coefficients of soot exhibited an increasing trend along the flame axis. However, mature soot retained a relatively high H/C ratio and low absorption coefficients with respect to other less hydrogenated fuels even in high temperature conditions. This indicates that the aromatization/dehydrogenation of soot in premixed flames is more dependent on the fuel characteristics rather than on the flame temperature.

Research paper thumbnail of Advantages and Shortcomings of Mass Spectrometric Techniques for the Analysis of Aromatic Compounds Relevant in Combustion

Research paper thumbnail of Distribution of Soot Molecular Weight/Size along Premixed Flames as Inferred by Size Exclusion Chromatography

Energy & Fuels, 2007

The evolution of size/molecular weight (MW) of soot from inception to mature soot was studied by ... more The evolution of size/molecular weight (MW) of soot from inception to mature soot was studied by means of size exclusion chromatography (SEC) coupled with on-line UV-visible spectroscopy of soot sampled along the flame axis of ethylene, hexane, and benzene premixed flames. Polystyrene calibration and microfiltration were used for the evaluation of the soot MW and size, respectively. Overall, soot exhibited a wide MW/size distribution peaking in two main regions, well detached from each other. The first corresponds with particles/ aggregates having MW > 20 000 u, here called the "particle-size region", and the second one corresponds with molecules in the 100-5000 u MW range called the "molecular-size region". The components in the particle-size regions dominated, particularly downstream of the flames and everywhere in the benzene flame. Two classes of components were evident in the particle-size region: one with d > 20 nm (MW > 59 500 u) and the second class well below 20 nm discriminated by SEC, coupled with microfiltration. Meaningful differences in the relative contributions of these two classes were found to occur along the flames, affected by the fuel aromaticity, and they were signatures of the soot growth process and of the different soot inception mechanisms in aliphatic and benzene flames respectively.

Research paper thumbnail of Advantages and limitations of laser desorption/ionization mass spectrometric techniques in the chemical characterization of complex carbonaceous materials

International Journal of Mass Spectrometry, 2010

Laser desorption/ionization techniques coupled with mass spectrometry analyzers have evolved rapi... more Laser desorption/ionization techniques coupled with mass spectrometry analyzers have evolved rapidly in the recent years and are currently capable of providing valuable information about the chemical composition and structure of very high molecular weight species, mainly biopolymers or synthetic polymers.

Research paper thumbnail of Similarities and dissimilarities in n-hexane and benzene sooting premixed flames

Proceedings of the Combustion Institute, 2007

The flame structure of atmospheric-pressure sooting premixed flames of aliphatic and aromatic hyd... more The flame structure of atmospheric-pressure sooting premixed flames of aliphatic and aromatic hydrocarbons with the same carbon atom number (hexane and benzene) were studied at similar temperatures and C/O ratios by sampling and chemical and spectroscopic analysis. The differences in the oxidation mechanism of hexane and benzene in fuel-rich conditions were found to produce a different chemical environment in the

Research paper thumbnail of Mass spectrometric analysis of large PAH in a fuel-rich ethylene flame

Proceedings of the Combustion Institute, 2007

Research paper thumbnail of Effect of fuel/air ratio and aromaticity on the molecular weight distribution of soot in premixed n-heptane flames

Proceedings of the Combustion Institute, 2009

Research paper thumbnail of Structure–property relationship in nanostructures of young and mature soot in premixed flames

Proceedings of the Combustion Institute, 2009

A structural description of young and mature soot sampled from methane, ethylene, cyclohexane and... more A structural description of young and mature soot sampled from methane, ethylene, cyclohexane and benzene premixed flames, burning in fuel-rich conditions, was performed by means of high-resolution transmission electron microscopy (HRTEM). HRTEM image analysis was carried out to achieve semiquantitative information about the soot organization. Different nanostructures were found to develop in the soot, depending on the fuel and on soot aging.

Research paper thumbnail of Vibrationally resolved high-resolution NEXAFS and XPS spectra of phenanthrene and coronene

The Journal of chemical physics, Jan 28, 2014

We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption ... more We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption Fine-Structure (NEXAFS) spectroscopy and X-ray Photoelectron Spectroscopy in the gas phase of two polycyclic aromatic hydrocarbons (phenanthrene and coronene), typically formed in combustion reactions. In the NEXAFS of both molecules, a double-peak structure appears in the C1s → LUMO region, which differ by less than 1 eV in transition energies. The vibronic coupling is found to play an important role in such systems. It leads to weakening of the lower-energy peak and strengthening of the higher-energy one because the 0 - n (n > 0) vibrational progressions of the lower-energy peak appear in nearly the same region of the higher-energy peak. Vibrationally resolved theoretical spectra computed within the Frank-Condon (FC) approximation and linear coupling model agree well with the high-resolution experimental results. We find that FC-active normal modes all correspond to in-plane vibrati...

Research paper thumbnail of Characterization of carbon particulate matter relevant in combustion

Research paper thumbnail of Size/molecular weight distribution in the nucleation mode of flame-generated soot

Research paper thumbnail of Soot nanostructure evolution in premixed flames by High Resolution Electron Transmission Microscopy (HRTEM)

Proceedings of the Combustion Institute, 2015

ABSTRACT HRTEM fringe analysis by means of our “Analyse Plan” (AP) tool and a new HRTEM image ana... more ABSTRACT HRTEM fringe analysis by means of our “Analyse Plan” (AP) tool and a new HRTEM image analysis procedure, based on mathematical morphological analysis (MA), was applied to soot sampled along the axis of sooting premixed benzene and ethylene flames. The layer length obtained by means of MA approach was found to be higher in respect to the layer length derived from AP method, as it better accounts for their local curvature and distortion. The mean layer length obtained by the MA method was then proved to agree well with the data evaluated by Raman spectroscopy. Moreover, the MA method was useful for extracting other soot nanostructural parameters related to the geometry of individual fringes as layer length, tortuosity, and local curvature radii, in turn correlated with the defective nature of soot structure. Some parameters provided by the MA method appeared to be more sensitive and informative about structural changes occurring as soot is formed. In particular, the percentage of fringes with high tortuosity and the percentage of nearly-straight fragments were found to decrease and increase, respectively, throughout the soot formation region. These trends suggested a better stacking of longer and more planar layers testifying the structural order improvement with soot aging. It was also observed that the soot nanostructural ordering occurred faster for benzene with respect to ethylene soot in agreement with H/C and absorption coefficients trends. The distributions of carbon in differently-sized aromatic structures were evaluated on the basis of the fringe length distribution to follow the aromatic growth. The method assigned aromatic sizes to the extracted HRTEM fringes, assuming that the fringes are in the shape of parallelograms. The distributions were found to evolve toward larger size aromatic systems demonstrating the occurrence of aromatic growth during soot formation.

Research paper thumbnail of Characterization of nanometric carbon materials by time-resolved fluorescence polarization anisotropy

Optics and Lasers in Engineering, 2006

Research paper thumbnail of Mass spectrometric analysis of large PAH in a fuel-rich ethylene flame

Proceedings of the Combustion Institute, 2007

Mass spectrometric analysis by laser desorption-time of flight-mass spectrometry (LDI-TOF-MS) was... more Mass spectrometric analysis by laser desorption-time of flight-mass spectrometry (LDI-TOF-MS) was exploited to extend the detection of flame-formed polycyclic aromatic hydrocarbons (PAH) up to the mass limit of the first soot particles (>2000 Da) in the soot formation region of a premixed fuel-rich (C/O = 1) ethylene flame. The typical decreasing intensity of PAH ion peaks with increasing mass was found in the mass range m/z 500-1700 although a slight enrichment in the heavier part of PAH could be observed to occur along the flame axis. The separation by means of size exclusion chromatography (SEC) into two different classes of PAH followed by UV-visible spectroscopy corroborated the mass spectral identification of large mass PAH. Critical examination of mass spectral features and SEC separation was the starting point for speculation about the changes occurring in PAH growth from planar to concave structures which could be important for soot inception mechanisms.

Research paper thumbnail of Analysis of the Impact of the Dual-Fuel Ethanol-Diesel System on the Size, Morphology, and Chemical Characteristics of the Soot Particles Emitted from a LD Diesel Engine

SAE Technical Paper Series, 2014

Research paper thumbnail of Diesel exhaust particle exposure in vitro impacts T lymphocyte phenotype and function

Particle and Fibre Toxicology, 2014

Background: Diesel exhaust particles (DEP) are major constituents of ambient air pollution and th... more Background: Diesel exhaust particles (DEP) are major constituents of ambient air pollution and their adverse health effect is an area of intensive investigations. With respect to the immune system, DEP have attracted significant research attention as a factor that could influence allergic diseases interfering with cytokine production and chemokine expression. With this exception, scant data are available on the impact of DEP on lymphocyte homeostasis. Here, the effects of nanoparticles from Euro 4 (E4) and Euro 5 (E5) light duty diesel engines on the phenotype and function of T lymphocytes from healthy donors were evaluated. Methods: T lymphocytes were isolated from peripheral blood obtained from healthy volunteers and subsequently stimulated with different concentration (from 0.15 to 60 μg/ml) and at different time points (from 24 h to 9 days) of either E4 or E5 particles. Immunological parameters, including apoptosis, autophagy, proliferation levels, mitochondrial function, expression of activation markers and cytokine production were evaluated by cellular and molecular analyses.

Research paper thumbnail of Chemico-physical features of soot emitted from a dual-fuel ethanol–diesel system

ABSTRACT The paper describes an experimental study aimed to characterize the impact of the dual-f... more ABSTRACT The paper describes an experimental study aimed to characterize the impact of the dual-fuel ethanol–diesel combustion system on size, number and chemical characteristics of the emitted carbonaceous particles. The tests were conducted on a single cylinder research engine provided with a modern architecture and properly modified in a dual-fuel (DF) configuration. In particular, the experimental campaign was aimed to evaluate in detail the effect of the use of the ethanol as port injected fuel in diesel engine on the size distribution function, morphology, reactivity and chemical features of the exhaust emitted soot particles. The engine tests were chosen properly in order to represent actual working conditions of an automotive light-duty diesel engine. The morphological and chemical features of soot particles were studied in dependence of the ethanol–diesel substitution rate by analyzing the soot collected at the engine exhaust. Results indicated a significant effect of ethanol fumigation on the concentration of the emitted particles but not on the average size, as well as, a negligible impact of ethanol premixed charge on the soot nanostructural features.