Morphology Of Particulate Matter Research Articles

습식 성장한 ULSD 입자상 물질의 물리적 및 화학적 특성 분석에 관한 연구

Condensation of water can affect the morphology of particulate matter (PM) produced from burning hydrocarbon fuel and thus their refractive index, eventually altering the light scattering properties of particles. Optical characteristics of PMs released in the air is an essential research to reduce uncertainty in terms of environmental and climate models. However, research results on the effect of hygroscopicity of particulate matter on optical properties are relatively insufficient. Therefore, in this study, optical characteristics were studied through physical and chemical analysis of Ultra Low Sulfur Diesel (ULSD) PM produced under different relative humidity conditions. While Transmission Electron Microscope(TEM) analysis was performed to confirm the physical shape, Raman spectra & total carbon analysis were performed to elucidate the degree of graphitization of carbon of PM. Results obtained from series of analyses clearly indicate that ULSD PM reacted with water to collapse the agglomerate structure into a compact form, thus resulting in an increase in the light scattering effect.

The microscopic characteristics of particle matter and image algorithm based on fractal theory

The effects of ash and sulfur content on the morphology of particulate matter (PM) in diesel particle filter (DPF) were investigated with five different components of lubricants. The aggregate morphology of primary particles in diesel were analyzed using transmission electron microscopy (TEM). The fractal dimensions of carbon particles were calculated by box-counting method (BCM), differential box-counting method (DBC), relative differential box-counting method (RDBC) and MAD-based box counting method (MAD-DBC), and the results were compared. The results showed that the microstructure of PM developed from chain-like structure to agglomerate structure with the increase of sulfur and ash content in lubricating oil. The fractal dimension of carbon particles increased with the increase of sulfur and ash content. The SSE of RDBC fitting results was smaller, and the R-square is larger. MAD-DBC fitting results had stronger anti-noise interference performance.

Extended filtration model for diesel particulate filter based on diesel particulate matter morphology characteristics

This study proposes an extended filtration model for diesel particulate filter based on diesel particulate matter morphology characteristics. This model introduces the parameter of variable effective density to modify the filtration model and develops the global filtration correction coefficient ϑp to consider the changes of PM morphological parameters. The specific calculation formulas of these two parameters are given in the paper. The filtration model proposed in this paper is based on the theory of spherical particles packed bed. Results show that the prediction error of the extended model can be as low as 0.66%, the average prediction error is 1.17%, and the prediction accuracy is improved by 34.08% compared with the former model. Filtration efficiency growth coefficient Egro exhibits a bimodal distribution, and the PM in the two particle size ranges of 110–140 nm and greater than 500 nm is more sensitive to the micro-changes in parameters caused by PM deposition in the porous substrate. In addition, the filtration time interval has the greatest influence on the growth rate, especially for the small and medium particle sizes ranging between 166.5 and 294.3 nm.

Influence of alternative fuels on combustion and characteristics of particulate matter morphology in a compression ignition diesel engine

The improvement of combustion and harmful emissions reduction has been driven by multiple factors; alternative fuels can be one of the important factors. In this study, Gas-to-Liquid (GTL) and Ethanol-RME-Diesel blend are used as an alternative fuels in a single cylinder diesel engine. The impact of alternative fuel on particulate matter (PM) characteristics and gaseous emissions were studied. These results reveal that ethanol blend increases the in-cylinder pressure and rate of heat release (ROHR) compared to the GTL and diesel fuel by 4% and 13% respectively. The particulate size distribution (PSD) was smaller from the combustion of ethanol blend compared to diesel and GTL fuel. The experimental results indicated that the ethanol blend produces smaller size of soot agglomerate and lower number of soot primary particles (npo) than to the rest of fuel. Furthermore, it can be observed that the soot particles emitted from ethanol blend has less spherical shape due to smaller fractal dimension (Df) than to the diesel and GTL fuel. It is found that the NOX emissions were lower from the combustion of GTL fuel than ethanol blend and diesel fuel.

Size-resolved composition and morphology of particulate matter during the southwest monsoon in Metro Manila, Philippines

Abstract. This paper presents novel results from size-resolved particulate matter (PM) mass, composition, and morphology measurements conducted during the 2018 southwest monsoon (SWM) season in Metro Manila, Philippines. Micro-orifice uniform deposit impactors (MOUDIs) were used to collect PM sample sets composed of size-resolved measurements at the following aerodynamic cut-point diameters (Dp): 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.32, 0.18, 0.10, and 0.056 µm. Each sample set was analyzed for composition of the water-soluble fraction. Analysis for mass was carried out on two sample sets, whereas black carbon (BC) and morphology analysis were analyzed on a single sample set. The bulk of the PM mass was between 0.18 and 1.0 µm with a dominant mode between 0.32 and 0.56 µm. Similarly, most of the black carbon (BC) mass was found between 0.10 and 1.0 µm, peaking between 0.18 and 0.32 µm. These peaks are located in the Greenfield gap, or the size range between 0.10 and 1.0 µm, where wet scavenging by rain is relatively inefficient. In the range between 0.10 and 0.18 µm, BC constituted 78.1 % of the measured mass. Comparable contributions of BC (26.9 %) and the water-soluble fraction (33.4 %) to total PM were observed and most of the unresolved mass, which amounted to 39.6 % in total, was for diameters exceeding 0.32 µm. The water-soluble ions and elements exhibited an average combined concentration of 8.53 µg m−3, with SO42-, NH4+, NO3-, Na+, and Cl− as the major contributors. Positive matrix factorization (PMF) was applied to identify the possible aerosol sources and estimate their contribution to the water-soluble fraction of collected PM. The factor with the highest contribution was attributed to “aged aerosol” (48.0 %), while “sea salt” (22.5 %) and “combustion” emissions (18.7 %) had comparable contributions. “Vehicular/resuspended dust” (5.6 %) and “waste processing” emissions (5.1 %) were also identified. Microscopy analysis highlighted the ubiquity of nonspherical particles regardless of size, which is significant when considering calculations of parameters such as single scattering albedo, the asymmetry parameter, and the extinction efficiency. The significant influence from aged aerosol to Metro Manila during the SWM season indicates that local sources in this megacity do not fully govern this coastal area's aerosol properties. The fact that the majority of the regional aerosol mass burden is accounted for by BC and other insoluble components has important downstream effects on the aerosol hygroscopic properties, which depend on composition. The results are relevant for understanding the impacts of monsoonal features on size-resolved aerosol properties, notably aqueous processing and wet scavenging. Finally, the results of this work provide contextual data for future sampling campaigns in Southeast Asia such as the airborne component of the Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex) planned for the SWM season in 2019.

Impact of bio-alcohol fuels combustion on particulate matter morphology from efficient gasoline direct injection engines

The requirements for controlling particulate emissions in gasoline direct injection (GDI) engines, particularly in hybrid vehicles (where frequent cold-start event impact on both, particles characteristics and catalytic aftertreament efficiency), nesesitates the need for understanding their formation mechanism and their morphological characteristics. The findings described in this investigation have significance in the design of efficient Gasoline Particulate Filters (GPFs) and the development of computational models that predict particle filtration and oxidation processes.Morphological analysis of the particulate emissions from the combustion of commercial gasoline and two bio-alcohol blends: of 25% v/v ethanol in gasoline and 33% v/v butanol and 67% v/v gasoline, in a modern GDI engine has been carried out using a transmission electron microscopy. The primary particle size distribution from the combustion of butanol-gasoline blend was slightly smaller compared to gasoline, while the mean primary particle diameter was 3 nm smaller from the combustion of ethanol-gasoline fuel. This decrease in primary particle size for ethanol-gasoline blend was also reflected in a reduction of the mean radius of gyration and mean number of primary particles per agglomerate.The combustion of butanol-gasoline blend induced improved particle oxidation rates during the combustion process and post-oxidation stage, and led in 80% and 60% reduction in particle concentration in the engine exhaust when compared to the combustion of gasoline and ethanol-gasoline blend, respectively. Additionally, the estimation of the particle fractal dimension through the use of fractal equation, minimum bonding rectangle method and root form factor showed comparable results for butanol-gasoline and gasoline, with the particle agglomerates being more compact than the ethanol-gasoline fuel, where more chain like particles are seen. Therefore, particles emitted from the combustion of ethanol-gasoline fuel are easier to be trapped (lower fractal dimension) and present a higher reactivity (high surface/volume ratio) compared to particles emitted from gasoline combustion.

Fuel formulation effects on the soot morphology and diesel particulate filter regeneration in a future optimized high-efficiency combustion system

The focus of research is shifting toward development of new engine fuels for optimized combustion systems. The altered chemical structure of these new fuels may impact their thermal decomposition chemistry during the ignition process and hence the in-cylinder conditions for particulate formation and post oxidation. This work fundamentally focuses on the influence of the fuel properties on particulate matter morphology and, thereby, the regeneration behavior of diesel particulate filters. The experiments for particulate analysis were conducted with a single-cylinder diesel research engine designed for future passenger car applications. A detailed analysis of soot characteristics and its consequences on diesel particulate filter behavior were studied at part-load engine operation at EU 6 engine-out nitrogen oxide level. Next to standard EN590 diesel, a paraffinic fuel was investigated as non-oxygenated biofuel candidate. A blend of the 2-methyltetrahydrofuran and di-n-butylether was studied as tailor-made oxygenated biomass-derived fuel candidate. With all fuels, samples of state-of-the-art diesel particulate filter were loaded at the research engine. In succession, the regeneration of the filters was investigated at a laboratory gas bench. Furthermore, the primary particle size, the total number concentration, and size-based number distribution were investigated in detail by means of a transmission electron microscope, condensation particle counter, and Engine Exhaust Particle Sizer™, respectively. Furthermore, the graphitic character of the soot structure was analyzed by optical measurements such as absorption coefficient. It was found that the soot oxidation temperature was decreased by ∼10 °C and ∼65 °C with the paraffinic fuel and the blend of 2-methyltetrahydrofuran and di-n-butylether, respectively, compared to conventional diesel fuel. Overall, the results indicate that with specific tailored fuels not only the total particle mass and number could be reduced but, with altering the soot structure and composition, also the energy requirement for diesel particulate filter regeneration can be reduced.

Particulate matter mass concentrations produced from pavement surface abrasion

According to the latest findings particulate matter belong to the most significant pollutants in Europe together with ground-level ozone O3 and nitrogen dioxide NO2. Road traffic is one of the main sources of particulate matter. Traffic volume has unpleasant impact on longevity of the pavements and also on the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The paper deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The paper offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

Laboratory Measurements of Particulate Matter Concentrations from Asphalt Pavement Abrasion

AbstractThe issue of emissions from road traffic is compounded by the fact that the number of vehicles and driven kilometres increase each year. Road traffic is one of the main sources of particulate matter and traffic volume is still increasing and has unpleasant impact on longevity of the pavements and the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The contribution deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures of wearing courses are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The contribution offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

Impact of exhaust gas fuel reforming and exhaust gas recirculation on particulate matter morphology in Gasoline Direct Injection Engine

Modern Gasoline Direct Injection (GDI) engines offer increased power output, improved fuel economy and reduced CO2 emissions. However, the increased particulate matter (PM) emission level still remains a challenging task. Understanding PM features such as morphological and microstructural parameters through transmission electron microscopy can provide information about their formation, filtration and soot oxidation processes in the gasoline particulate filters and their impact on human health. This research article characterises PM emitted from a 2L 4-cylinder GDI engine at two injection timings: (i) ECU settings which produces PM with high volatile content and (ii) advanced injection timing to increase soot formation rate. Primary particle size distributions formed by volatile nature PM, present a higher standard deviation than for the sooty PM, while the former ones presented higher fractal dimension. In addition, five different methods of estimating PM fractal dimension reported in the GDI literature have also been compared and it was concluded that the arising trends were in agreement. The effect of high percentages of exhaust gas recirculation (EGR) and reformate gas combustion on PM characteristics have been analysed. EGR does not have a significant effect in PM morphology. On the other hand, reformate combustion reduces the size of the primary particle and the agglomerates as well as increasing the fractal dimension.

Effect of Drive Cycle and Gasoline Particulate Filter on the Size and Morphology of Soot Particles Emitted from a Gasoline-Direct-Injection Vehicle.

The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, that is, the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions. The mean projected area-equivalent diameter of these aggregates is in the 78.4-88.4 nm range and the mean diameter of primary particles varies between 24.6 and 26.6 nm. Post-GPF particles emitted over the US06 cycle appear to have an amorphous structure, and a large number of nucleation-mode particles, depicted as low-contrast ultrafine droplets, are observed in TEM images. This indicates the emission of a substantial amount of semivolatile material during the US06 cycle, most likely generated by the incomplete combustion of accumulated soot in the GPF during regeneration. The size of primary particles and soot aggregates does not vary significantly by implementing the GPF over the FTP-75 cycle; however, particles emitted by the GPF-equipped vehicle over the US06 cycle are about 20% larger than those emitted by the stock-GDI vehicle. This may be attributed to condensation of large amounts of organic material on soot aggregates. High-contrast spots, most likely solid nonvolatile cores, are observed within many of the nucleation-mode particles emitted over the US06 cycle by the GPF-equipped vehicle. These cores are either generated inside the engine or depict incipient soot particles which are partially carbonized in the exhaust line. The effect of drive cycle and the GPF on the fractal parameters of particles, such as fractal dimension and fractal prefactor, is insignificant.

Characterization of Particulate Matter Morphology and Volatility from a Compression-Ignition Natural-Gas Direct-Injection Engine

The particulate matter (PM) emitted from a single-cylinder compression-ignition, natural-gas engine fitted with a High-Pressure Direct-Injection (HPDI) system distinctly different from a duel fuel engine was investigated, and characterized by size distribution, morphology, mass-mobility exponent, effective density, volatility, mixing state, and primary particle size using transmission electron microscopy (TEM), and tandem measurements from differential mobility analyzers (DMA) and a centrifugal particle mass analyzer (CPMA). Six engine conditions were selected with varying load, speed, exhaust gas recirculation (EGR) fraction, and fuel delivery strategy. An increase in engine load increased both the number concentration and the geometric mean diameter of the particulate. The fraction of the number of purely volatile particles to total number of particles (number volatile fraction, NVF) was found to decrease as load increased, although at the lower speed, partially premixed mode, the lowest NVF. All size d...

Comparative Study on Particles Formation in a Diesel Engine When Lubricating Oil Involved in Fuel Combustion

The effect of lubricating oil on the morphology of particulate matter (PM) was studied in a diesel engine fueled with pure diesel fuel and blended fuel containing 0.5% by weight of lubricating oil. Particulate matter emitted by diesel engines is formed primarily by soot agglomerates which are composed of primary particles. In this paper, particulate matter was collected with a thermophoretic sampling system, and a high-resolution transmission electron microscope (TEM) was used to investigate the primary particles. A Fast Particulate Spectrometer, DMS 500, was used to determine the particle size distributions. The TEM results indicated that the mean diameters of the primary particles increased after the oil was added into the fuel. Particle size distributions results showed that lubricating oil in the fuel gave rise to a higher concentration in nucleation mode.

Characterization of the Morphology of Particulate Matter inside Farm Houses Located near Biosolids-Applied Agricultural Fields

AbstractLand application of biosolids to improve the fertility of agricultural land is very common in the United States. Bioaerosols are airborne particulate matter (PM) aerosolized during various agricultural processes such as preapplication preparation, disking, application, and postapplication management. In recent years, there has been concern about the health of people living near the application sites even though these processes have been going on for decades. The focus of this study is to characterize PM inside households located near fields where biosolids have been applied. The PM was collected inside five houses on eight polytetrafluoroethylene (PTFE) filter papers using the GRIMM 1.108 dust monitor. Physical characteristics of PM were analyzed using the scanning electron microscope (SEM). The morphological properties of particles such as diameter, area, perimeter, aspect ratio, and shape factor of particles were determined using Image J software for the images captured using SEM. It was observe...

Urban Air Pollution by Nanoparticles in Ostrava Region

Air pollution harms human health and the environment. Ostrava's agglomeration and its immediate vicinity suffer regular exceeding of air pollution limits due to its geomorphologic location and present heavy industry. Maximum exceedances of air quality standards and especially PM10 which 24 hour limit value is in EU 50μg.m-3, must not be exceeded more than 35 days per year. This limit is being still often exceeded. In the year 2011 such as situation occurred 126 times. It is very important then for identify sources of air pollution to find out maximum information about air borne dust, like size distribution, chemical composition of individual size fractions, morphology of particulate matter together with other parameters like meteorological conditions, year season etc. Our measurement started two years ago. We focus on the critical situation when there are values of PM10 over a long period above the limit. In winter season it is so called inversion. By default, during the campaign it is measured size distribution of air born dust in range 5.6 nm −560nm by FMPS and using the sampler NanoId are collected samples in range 1nm – 35μm in 12 size fractions for chemical analysis and morphological observations. This contribution deals with results of size distributions only.

A lumped parameter model for diesel soot morphology evaluation and emission control

Diesel engine emission standards have become more and more severe in recent years. The use of diesel particulate filters (DPFs) is a consolidated technology to reduce the emission of particulate matter out of such engines. This work is aimed at presenting a global lumped parameter for onboard applications to estimate soot morphology and its effects on DPF performances. Starting from diesel soot production during combustion, soot morphology is evaluated in terms of fractal dimension and radii of gyration. The morphology of particulate matter influences the permeability of soot deposit inside the DPF: the growth of soot layer and the consequent pressure loss are evaluated during the loading phase in different sections of the trap. Finally, the temperature trend during regeneration is computed, as a function of the amount of soot accumulated in the different zones of the DPF. The results are compared to experimental measures from the literature and to 3D-computational fluid dynamics (3D-CFD) simulations.

Characterization of indoor and outdoor atmospheric pollutants impacting architectural monuments: the case of San Jerónimo Monastery (Granada, Spain)

Indoor and outdoor concentrations of atmospheric gaseous pollutants as well as composition, size, and morphology of particulate matter have been investigated at the monastery of San Jeronimo in Granada (Southern Spain). Complementary micro- and nano-analytical techniques were applied; elemental and mineralogical composition and morphological characteristics of particulate matter were investigated combining electron probe microanalysis at the single particle level, and bulk aerosol samples were analyzed using energy-dispersive X-ray fluorescence, X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray analyzer and transmission electron microscopy (TEM). Microclimatic conditions at the monastery were monitored, and gas concentrations were assessed by means of diffusion tubes subsequently analyzed with ion chromatography. Results revealed high abundances of soil dust particles (aluminosilicates, calcite, dolomite, quartz), salt aerosols (chlorides, sulfates and ammonium-rich salts), and NO2 and SO2 both outdoors and indoors. Amorphous black carbon particles had surprisingly high abundances for Granada, a non-industrialized city. The composition of indoor particles corresponds to severe weathering affecting the construction materials and artworks inside the church; moreover their composition promotes a feedback process that intensifies the deterioration. Chemical reactions between chloride-rich salts and pigments from paintings were confirmed by TEM analyses. Indoors, blackening of surface decorative materials is fostered by particle re-suspension due to cleaning habits in the monastery (i.e. dusting). This is the first air quality study performed in a monument in the city of Granada with the aim of developing a strategy for preventive conservation.