Mariano Sirignano

University of Naples Federico II | UNINA · Department of Chemical, Materials and Industrial Production Engineering

Carbon nanomaterials have been widely applied for cutting edge therapeutic applications as they offer tunable physio-chemical properties with economic scale-up options. Nuclear delivery of cancer drugs has been of prime focus since it controls important cellular signaling functions leading to greater anti-cancer drug efficacies. Better cellular dru...

The paper reports a detailed study on carbon particulate matter (PM) sampled in ethylene flames stabilized on a burner-stabilized stagnation (BSS) system, aiming to give more insights on the characteristics of particles produced in this peculiar flame configuration. The study employs various diagnostic tools to analyze PM collected on the stagnatio...

Despite their hazardous nature, carbonaceous particles (CPs) own very appealing properties, which make them a leading material in numerous applications. A systematic work on the properties of aqueous dispersions containing CPs, cetylpyridinium chloride (CPyCl), and sodium salicylate (NaSal) is here presented. Being CPs not soluble in water, an effe...

Wettability, typically estimated through the contact angle, is a fundamental property of surfaces with wide-ranging implications in both daily life and industrial processes. Recent scientific interest has been paid to the surfaces exhibiting extreme wettability: superhydrophobic and superhydrophilic surfaces, characterized by high water repellency...

Alternative synthetic fuels can be produced by renewable energy sources and represent a potential route for solving long-term energy storage. Among them, oxygenated fuels have the advantage of significantly reducing pollutant emissions and can therefore be used as carbon-neutral substitute fuels for transportation. In this work, the sooting propens...

The emissions of diesel engines in terms of particulate matter are limited all over the world. One possible solution for reaching the target imposed by the various regulations could be the adoption of a catalytic diesel particulate filter (CDPF). Nevertheless, the effect of CDPFs on the particle size distributions (PSDs) during the regeneration pro...

This work reports the implementation and the validation of the extrapolation method for thermocouple temperature measurements corrected from the radiation losses in sooting flames. This simple method relies on the use of thermocouples having different size diameters and enables a fast and direct determination of the flame temperature by extrapolati...

Carbon nanomaterials are an inventive class of materials with wide applications in state-of-the-art bioimaging and therapeutics. They allow a broad range of tunable and integrated advantages of structural flexibility, chemical and thermal stability, upright electrical conductivity, and the option of scale-up and mass production. In the context of n...

The reduction of carbon emissions is leading to alternative and renewable energy sources. Solar or wind sources can only be regulated to a limited extent and fluctuate considerably due to environmental conditions, which could be overcome by chemical energy storage solutions. Synthetic fuels are chemical energy carriers that can be produced using ex...

Flame synthesis could represent a controllable method for production of carbon dots (CDs) with tunable emission properties, alternative to process involving oxidation agents and wet chemistry processing. To control final properties of CDs, a thorough analysis of different reactor parameters has to be conducted. Here we investigate the effect of com...

Alternative synthetic fuels can be produced by renewable energy sources and represent a potential route for solving long-term energy storage. Among them, oxygenated fuels have the advantage of significantly reducing pollutant emissions and can therefore be used as carbon-neutral substitute fuels for transportation. In this work, the sooting propens...

Synthetic fuels, especially oxygenated fuels, which can be used as blending components, make it possible to modify the emission properties of conventional fossil fuels. Among oxygenated fuels, one promising candidate is oxymethylene ether-3 (OME 3 ). In this work, the sooting propensity of ethylene (C 2 H 4 ) blended with OME 3 is numerically inves...

A sectional scheme for soot formation is combined with a novel model for coagulation efficiency based on the thermal rebound concept and involves the minimisation of the Lennard-Jones potential energy between two colliding particles. Here, a novel generalisation of the interaction potential well depth is formulated for particles of any size or mate...

The reduction and control of particulate matter generated by fossil fuel combustion are among the main issues for actual and future combustion devices due to the increasingly stringent emission regulations. Recently, various fuels have been investigated as a potential substitute or additive for diesel and gasoline. This work focuses on how oxymethy...

A detailed experimental characterization of the particle emissions of a EURO 5 light-duty Diesel engine, equipped with a wall flow Diesel Particulate Filter (DPF), is presented. Particle Size Distributions (PSDs) in the range from 4.5 up to 160 nm have been measured at the engine exhaust by means of a Scanning Mobility Particle Sizer, during both D...

There is a need to better understand particle size distributions (PSDs) from turbulent flames from a theoretical, practical and even regulatory perspective. Experiments were conducted on a sooting turbulent non-premixed swirled ethylene flame with secondary (dilution) air injection to investigate exhaust and in-burner PSDs measured with a Scanning...

The effect on soot formation of carbon dioxide addition as diluent in ethylene/O2/Ar laminar counter flow diffusion flames has been examined both experimentally and with the help of a multi-sectional kinetic model. Different concentrations of CO2 have been used in the oxidizer stream to replace argon, whereas the amount of oxygen has been kept cons...

Soot particle size distribution (PSD) evolution in an ethylene lab-scale swirl Rich-Quench-Lean (RQL) combustor is investigated using a detailed physicochemical sectional soot model coupled with the Conditional Moment Closure turbulent combustion model and Large Eddy Simulation. The aim is to develop predictive capability for the local soot PSD and...

In this work soot formation was studied in a series of laminar premixed flames fueled with binary heptane-toluene mixtures. The equivalence ratio (φ = 2), the cold gas velocity and the total carbon flow rate were kept constant changing accordingly the oxygen content and the diluent (N2) concentration. A very similar temperature up to 80% of toluene...

The reduction and control of particulate matter generated by fossil fuel combustion are among the main issues for actual and future combustion devices due to the increasingly stringent emission regulations. Recently, various fuels have been investigated as a potential substitute or additive for diesel and gasoline. This work focuses on how oxymethy...

Coupling of traditional combustion technologies with solar thermal energy is fundamental to enlarge the field of applicability and to lower the costs of renewable energy sources. A possible solution is represented by direct irradiation of a flame with concentrated solar energy, so as to increase its temperature thanks to the high absorption coeffic...

In this paper, we estimate the degree of crosslinking within soot particles making use of reactive molecular dynamics simulations of mechanical properties of crosslinked polycyclic aromatic hydrocarbons (PAH). Representative systems of PAH (pyrene, coronene, ovalene and circumpyrene) with a density similar to soot and with varying degrees of crossl...

reactor synthesis approach in which the key tunable parameter is the fuel composition. Specifically, the properties of CNP including fluorescent nanocarbons could be varied by fueling a premixed flame with mixtures ranging from ethylene to benzene. CNP characterizationwas carried out through Raman and UV eVisible spectroscopy defining their in-plan...

This paper focuses on the soot inception region in laminar coflow diffusion flames of methane and ethylene stabilised on the Yale diffusion burner. Earlier studies of these flames have focused on the downstream regions where soot has already developed. Laser-induced fluorescence (LIF) and elastic scattering measurements from 266 nm excitation are c...

Background: Air pollution is becoming a threatening issue for human health. Many epidemiological studies relate air pollution index to adverse effects in terms of disease incidence and/or disease exacerbation. In our previous studies, we found air pollutants can induce the release of pro-inflammatory cytokines from human peripheral blood cells. To...

Soot evolution in an ethylene lab-scale Rich-Quench-Lean (RQL) combustor is investigated using a sectional model coupled with the Conditional Moment Closure turbulent combustion model with detailed chemistry and Large Eddy Simulation. The focus is on developing capability for capturing particle size distributions (PSD) locally and as function of th...

In this work soot formation was studied in laminar premixed flames of binary ethylene-benzene mixtures varying throughout the composition range from pure ethylene to pure benzene keeping constant the equivalence ratio (φ = 2) and obtaining a very similar maximum temperature (Tmax around 1750 K). In such way, it was possible to study for the first t...

The effect of the butanol isomers on carbon particulate matter formation was studied by substituting up to 20% of the total carbon of ethylene, fed to premixed flames with different equivalence ratios, with the four butanol isomers. Soot and condensed-phase nanostructures were tracked by means of particle size distribution (PSD) measurements and la...

A detailed gas-phase kinetic model coupled with a multi-sectional approach for the particle phase was used for inferring the effect of toluene addition on the sooting structure of a fuel-rich laminar premixed methane flame. Premixed methane flames at different C/O ratios established the reference environments to gain insight on the influence of tol...

This study focuses on the effects of carbon dioxide (CO2) dilution on the formation of soot and soot precursors in oxygen enhanced environment. Four axi-symmetric laminar coflow diffusion flames stabilized on a Yale burner are studied. CO2 is injected either in the jet stream, or co-flow stream, or both streams. Ultraviolet and Infrared range pulse...

This study highlights the effects of coflow oxygen concentration on soot and soot precursors in axi-symmetric laminar coflow diffusion flames stabilized on a Yale laminar coflow diffusion burner. Ultraviolet and Infrared range pulsed lasers are utilised to excite soot-precursors and soot particles respectively. Time-resolved laser induced fluoresce...

Particle size distributions (PSDs) are measured at the exhaust of a diesel engine burning a sulphur-free diesel fuel and a blend of the fuel with a rapeseed methyl-ester. Different operating conditions of load and engine speed are analyzed. Particles with sizes ranging from few nanometers up 1 µm are generated during combustion in the engine. Opera...

A coordinate measurement approach using remote sensing and near surface instruments has been carried out in the Campania region of Italy with the aim to understand as the anthropogenic sources linked to urban activities (waste disposal, vehicle traffic, and domestic heating) can influence the values of airborne particulate matter (PM) measured at g...

Recently improved knowledge about key processes for the formation and growth of soot particles lead to very extensive soot models describing several kinetic pathways for particle nucleation and growth in detail. One of these models has been proposed by D'Anna and coworkers (D'Anna et al., 2010, Sirignano et al., 2010). In these original studies, th...

Particle size distributions are measured at the exhaust of a passenger-car diesel engine burning a Sulphur-free diesel oil. Different operating conditions of loads and engine speed, representative of low-loads are analyzed. Particles with sizes ranging from few nanometers up 1 µm are generated during diesel combustion. Operating conditions strongly...

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 paper, we propose a semi-physical model for the burning of vegetation in a wildland fire. The main physical-chemical processes involved in fire spreading are modelled through a set of ordinary differential equations, which describe the combustion process as linearly related to the consumption of fuel. The water evaporation process from leav...

Stacking of polycyclic aromatic hydrocarbons is recognized as a key step in particle inception process in hydrocarbon-rich combustion. A conclusive description of the process is not reached, indeed uncertainties remain on the molecules involved in the process and on their intermolecular potential function. A study of the evolution of coronene (C24H...

Chronic obstructive pulmonary disease (COPD) is considered the fourth-leading causes of death worldwide; COPD is caused by inhalation of noxious indoor and outdoor particles, especially cigarette smoke that represents the first risk factor for this respiratory disorder. To mimic the effects of particulate matter on COPD, we isolated peripheral bloo...

The stimulation of healthy non-smoker [white bars (A)], smoker [dotted bars (B)], and chronic obstructive pulmonary disease [black bars (C)] with coronene (10 pg/ml) or pyrene (10 pg/ml) induced the release of IL-18. Control (CTR) represents untreated cells. Data are presented as the means ± SEM (n = 7). Statistically significant differences were d...

The sooting tendency of three C9H12 isomers, specifically n-propylbenzene, iso-propylbenzene and 1,3,5-trimethylbenzene (also known as mesitylene), was studied in atmospheric pressure, counter-flow diffusion flames of ethylene, whose fuel stream was doped with C9H12 isomers, added such that 10%, 20% and 30% of the total carbon was fed as aromatic c...

Ultrafine particles (UFP) generated by combustion processes are often associated with adverse health effects. However, little is known about the inflammatory processes generated by UFP that may underlie their toxicological activity. Murine macrophages (J774.1 cells) and human peripheral blood mononuclear cells (PBMCs) were used to evaluate the mole...

Soot formation in combustion represents a complex phenomenon that strongly depends on several factors such as pressure, temperature, fuel chemical composition, and the extent of premixing. The effect of partial premixing on soot formation is of relevance also for real combustion devices and still needs to be fully understood. An improved version of...

Real-time monitoring of local equivalence ratio is of primary importance for chemical combustion efficiency improvement. Chemiluminescence and laser induced breakdown spectroscopy (LIBS) measurements can be powerful tools for sensing equivalence ratio. Radicals such as OH*, CH*, and C2* are chemically formed within the flame front and consequently...

This paper presents both in-situ and ex-situ measurements of nanostructures (also loosely referred to as nanoparticles) in laminar flames with the purpose of providing an understanding of their evolution to soot. Two laminar flame burners are studied covering a range of C/O ratios and hence different sooting propensities. Ex-situ measurements, util...

An ethylene\ethanol premixed flame has been investigated to elucidate the effect of ethanol addition onto particle morphology and chemical features in controlled flame conditions. In-situ optical techniques and ex-situ on-line particle size distribution measurements showed that soot formation is strongly reduced for effect of ethanol addition to et...

Particle nucleation remains one of the most intriguing steps in the process of particle formation in flames. Although stacking/clustering of polycyclic aromatic hydrocarbons (PAHs) has been identified as a key step in the nucleation process, uncertainties remain about the size of the PAHs undergoing clustering, the organisation of the PAHs in the f...

In this work, a detailed kinetic mechanism for soot formation and evolution (D'Anna et al. 2010) is implemented in a method of moments framework using the concept of ‘Conditional Quadrature Method of Moments’ (CQMOM) (Yuan and Fox, 2011). Particle nucleation and growth pathways are described in detail tracking moments of the number density function...

A point-wise, time-resolved optical technique is employed to track simultaneously the evolution of soot particles and soot precursors in a turbulent flame of ethylene/nitrogen (1/1 by vol.). A picosecond laser, 80 ps@266 nm is used to measure scattering and laser-induced fluorescence (LIF) in selected UV and visible bands while Laser-induced incand...

In this work soot oxidation induced-fragmentation is modeled by using a Multi-Sectional approach. The model has been developed previously and applied successfully, confirming the role of oxidation-induced fragmentation in soot burnout under different combustion conditions. The Multi-Sectional model was used without further modification to understan...

Furanic fuels have been recently investigated because they are considered possible fossil fuel substituents due to their high energy density, their renewable origin and consequently low green-house gas emissions. Few data are available about the behaviors of these fuels in laboratory flame reactors. We have recently studied their sooting tendency i...

Biofuels, as alternative source of energy to fossil fuels, when burned in retrofitted combustion devices, have to respect the emission standards in terms of gaseous and particulate by-product emissions. Experimental findings show that biofuels generally decrease the amount of particulate matter produced and emitted from combustion systems. However...

Carbon particulate matter formed in fuel-rich atmospheric pressure premixed flames of ethylene and ethylene doped with 2,5 dimethyl furan (DMF) (20%) was analyzed in order to investigate the effect of fuel-borne oxygen on soot nanostructure and chemical functionalities. Particles were thermophoretically sampled on quartz plates and analyzed by tech...

Combustion generated ultrafine particles are believed to have an effect on human health. Their presence in the atmosphere is mainly attributed to outdoor sources, but they may also form indoor. Gas cooking is a widely diffused indoor activity commonly considered environmentally clean, and without emissions of particulate matter. However, even bluis...

The sooting tendency of four C8H10 isomers, specifically ethylbenzene, ortho-, meta- and para-xylene, has been studied in atmospheric pressure, counter-flow diffusion flames of ethylene, whose fuel stream was doped with 10%, 20% and 30% of C8H10 isomers. In-situ spectroscopy, namely laser UV-induced emission, is used as diagnostic tool to detected...

Particle oxidation is one of the steps still not completely understood in combustion. Most of the approaches are based on semi-empirical reaction rates. Correct evaluation of oxidation is needed to predict the final emission of particles in diffusion flames. Fragmentation has recently been proposed to be a controlling step in determining global soo...

Furans have recently raised as possible transportation fuels which can be produced from biological sources and biotechnological methods. Their role on combustion-generated particle formation results quite unexplored. Few studies showed that dimethylfuran (DMF) among the other furanic hydrocarbons seems to have a great tendency to form soot precurso...

The role of dimethyl ether (DME) as substituent to ethylene on particulate formation has been evaluated in premixed and counter-flow diffusion flames. In the premixed flame, the equivalence ratio has been changed from 1.95 to 2.61 and dimethyl ether has been added from 2% to 30% of the total carbon fed. In the counter-flow diffusion flame, the addi...

Coagulation of combustion-generated particles has been investigated in low and intermediate temperature regimes in a tubular reactor with a residence time of 1.65 s. Particles, generated by premixed ethylene/air flames with equivalence ratios above the soot threshold limit, are fed to a tubular reactor, which can be operated at temperatures up to 6...

An advanced multi-sectional approach for modeling the gas-to-particle process in flames is presented. It follows the chemical evolution and the internal structure of particles formed in flames, fully coupled with the main pyrolysis and oxidation of the fuel. The multi-sectional method is included in a detailed mechanism of hydrocarbon pyrolysis and...

A detailed kinetic mechanism of aromatic growth, particulate formation, and oxidation is presented and is tested in nonpremixed laminar flames of methane and ethylene at atmospheric pressure. Model development is refined in strict connection with new experimental data on the formation and oxidation of high molecular mass compounds and incipient par...

In the present study a laminar premixed ethylene flame was doped with different amounts of ethanol in order to understand the influence on biofuels in the total amount of particulate matter and the size distribution functions of the formed carbonaceous particles. Four different flames were investigated: one of pure ethylene as reference and three w...

The role of ethanol, as substituent to ethylene, on the formation of particulate matter has been investigated in different flame configurations by using in situ optical techniques. Laser induced fluorescence and incandescence signals, correlated to small precursor nanoparticles and large soot particles, respectively, have been measured in premixed...

Different sampling apparatus have been proposed to withdraw particles from combustion systems. All of them induce perturbations, mostly on the temperature and the velocity field inside the flame. Generally, to avoid artifacts due to velocity field perturbation, the sampling system is set up to obtain isokinetic probing of the combustion products, a...

Spectral and time-resolved fluorescence and incandescence measurements are used to identify aromatic compounds and particles in an atmospheric-pressure opposed-flow flame of ethylene. The fourth harmonic radiation, at 266 nm, of a Nd–YAG laser is used to excite electronic transitions in aromatic intermediates resulting in different laser induced em...

The evolution of the molecular weight (MW) distribution and structural properties of carbon particulate formed in methane, ethylene and benzene fuel-rich premixed flames, burning in similar conditions of maximum flame temperature, was experimentally measured and modeled.Both solubility and chromatographic separation of the carbon particulate allowe...

A detailed model of particle inception is proposed to delve into the physical structure and chemistry of combustion-formed particles. A sectional method is used, from a previously developed kinetic mechanism of particle formation with a double discretization of the particle phase in terms of C and H atom number. The present model also distinguishes...

A kinetic modeling approach is proposed to delve into the nature and chemistry of combustion-produced particles. A sectional method is used for the first time on this purpose. It is based on modeling of gas-to-particle transitions by sections containing 125 lumped species with C numbers ranging from 24 to 4 × 108 and H/C ratio ranging from 0 to 1....

Syngas has gained increasing attention due to the possibility that it is produced by coal and biomass. In order to develop more efficient processes suitable for different combustion conditions, a study of the kinetic of syngas ignition was carried out. Several kinetic mechanisms present in the literature were compared with experimental data. Differ...

Measurements of ultrafine particles have been performed at the exhaust of a low emission microturbine for power generation. This device has been fuelled with liquid fuels, including a commercial diesel oil, a mixture of the diesel oil with a biodiesel and kerosene, and tested under different loads. Primarily attention has been focused on the measur...

New challenge in combustion is the extended use of "clean" fuels, such as methane, in "particle free" combustion devices. Although large efforts have been made, actual combustion systems burning methane are still source of particulate that might be emitted in the atmosphere. In this paper measurements of ultrafine particle emission from premixed la...

In the last years increased interest in pollution control focused on the particulate emission from real combustion systems. These particles are usually not relevant for the total mass of particulate emitted, but become predominant in a concentration number analysis. Measurements have been conducted at the exhaust of an EUR05 diesel engine, in order...

An experimental and numerical study on particles inception and growth is performed in opposed-flow diffusion flames of ethylene and air characterized by different sooti