This study was conducted to investigate PM emissions and performance of SI engines fueled with butanol-methanol-gasoline during air dilution operation. Iso-butanol and methanol were blended with gasoline at volume concentrations of up to 40% (10, 20 vol% iso-butanol and methanol, respectively). The effects of lean mixture on engine performance and PM emissions with blends were investigated to find

A numerical analysis is presented of the neutralization of a dilute electrospray by a corona discharge of polarity opposite to that of the spray droplets in the gap between two parallel disks charged to different electric potentials. An Eulerian description of the spray is combined with a transport equation for the corona ions and mass and momentum conservation equations for the gas. Two configurations

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The article noted above presents and discusses results which have been already presented in a previously published article by the same authors: https://doi.org/10.3390/ecas2017-04131 and additionally contains identical passages to the same previously published article

The Differential Mobility Analyzer (DMA) is currently the most effective instrument for sizing sub-micrometer aerosol particles. An important requirement to ensure good performance in terms of sizing accuracy and resolution is that the flow field remains laminar and undisturbed along its classification zone. To achieve that, a flow straightener (or flow laminarizer) is employed at the sheath flow inlet

Analysis of the stable carbon isotope 13C in organic carbon (OC) can give insight into sources and atmospheric processing of carbonaceous aerosols, provided the 13C source signatures are known. However, only few data on 13C signatures of OC emitted by common sources of carbonaceous aerosol are available in Europe. We present and evaluate an improved version of a measurement method (1) to obtain δ13C

The activity size distributions of cosmogenic 7Be and the longer living radon progenies 210Pb and 210Po in urban aerosols were measured for summers and winters from, 2014 to the end of 2017.The average seasonal activity median aerosol diameters (AMADs) and mass median aerosol diameters (MMADs) calculated for summer ranged from 0.329 μm to 0.733 μm and were ordered AMADBe-7,

In silico methods can be used to estimate regional deposition of inhaled aerosols in regions of the lung that are inaccessible by direct measurements. Knowledge of deposited dose is important for assessing the efficacy of inhaled pharmaceutical aerosols or the impact from exposure to environmental pollutants. Although patient-specific geometries of the upper airways are widely used nowadays, insufficient

The application of standard online instrumentation, such as scanning mobility particle sizer (SMPS), centrifugal particle mass analyzer or aerosol particle mass analyzer (CPMA/APM), and electrical low-pressure impactor (ELPI+) to low-pressure processes is only possible with extensive modification of the devices and extensive calibrations. A low-pressure ejector is a suitable device to transfer aerosol

The role of the interaction of gas molecules with a surface on the diffusiophoretic force and velocity of a spherical aerosol particle is studied under the conditions of a free molecular regime. Expressions of these physical quantities are obtained for the arbitrary scattering kernels of different species of molecules. Calculations of the force and velocity of diffusiophoresis are carried out with

Spark discharge generators enable a fast, reliable, continuous, and highly reproducible production of nanoparticle aerosols along with a widely tunable size distribution. Graphite spark discharge generators have been particularly applied for studies of instrument calibration, filter testing, soot reactivity studies, and in toxicological risk evaluation of soot. Until now, it has been consensus that

A review of methodologies to measure the bipolar charge distribution of nanoparticles is completed, including their advantages/disadvantages and sequential development. This summary also provides context for a new development, which uses an Aerodynamic Aerosol Classifier (AAC) and Differential Mobility Analyzer (DMA) in tandem for a similar purpose. It is demonstrated that the tandem AAC-DMA system

The paper proposes a methodology to fill a gap in the context of mechanistic particle resuspension models related to the adhesion and lift force lever arms (a): to date, only one experimental observation exists from a centrifuge experiment with a specific particle/surface pair which found rP/a = 100 and assumed that the contact points were symmetric with respect to the particle center (Reeks, M.W.

Recent studies have shown that small expired droplets that contain pathogens may play a significant role in the transmission of respiratory diseases. However, there is little data on the generation of droplets from the bronchioles and their deposition in the lower airways during exhalation. We apply a computational fluid dynamics method to study expiratory air flow in a truncated model of the adult

The behavior of salt particles on a surface filter exposed to a high humidity gas flow and water droplets was studied to gain a better understanding of the influence of water content in its different states on the operational performance of such filters. Two sets of experiments were carried out: in both, polydisperse sodium chloride particles were filtered from a dry air stream onto hydrophobic filter

Aerosol filtration in fibrous filters is one of the principal methods of accurate removal of particulate matter from gas stream. The classical theory of depth filtration in fibrous structures is based on the assumption of existence of single fiber efficiency, which may be used for calculation of overall efficiency of the filter. There are several reasons for inappropriate estimation of the single fiber

Monopolar electrosurgical pencils are used extensively in surgical operations. With such pencils, electric current passes to the tissue, and as such, electrosurgical pencil operation generates a significant amount of thermal energy, which in turn leads to the generation of electrosurgical smoke (ES). The health risks of ES are dependent on the size distributions as well as the morphologies of the produced

Solid or liquid particles within a carrier gas may be deposited on solid surfaces exposed to the gas stream and, in some practical applications, these aerosol deposits have deleterious effects. In order to mitigate these effects, particle repulsive fields may be applied near the surface to reduce the deposition rate. A current blowing through the exposed surface may play this repulsion role with such

Electrostatic charging and deposition of a liquid nano-aerosol was studied in dry air and in technical (3.6 % O2) nitrogen. The experiments have shown that electronic charging of aerosols can be important in technical scale electrostatic precipitators (ESPs). Already at operation voltages just slightly above the corona onset voltage, the contribution of the free electrons to the overall current is

Drift tubes (DT) are prominent tools to classify small ions in the gas phase. This is in contrast with its limited use in the aerosol field at atmospheric pressures where the differential mobility analyzer (DMA) has been the tool of choice. While the DMA has been successful, it does not normally achieve the resolution of a common DT. On the other hand, the size range of the DT is limited as well as

In this study, the unsteady airflow field in a realistic model of human upper airways during the breathing cycle and the fibrous particle transport and deposition were investigated using the CFD method. An anatomically realistic model of airway passage including vestibule to the end of the trachea was constructed from the CT images of a 24-year-old healthy woman. Several user-defined functions (UDFs)

Based on the prior work of Chahl and Gopalakrishnan (2019) to infer particle-ion collision time distributions using a Langevin Dynamics (LD) approach, we develop a model for the non-dimensional particle-ion diffusion charging collision kernel βi or H that is applicable for 0≤ΨE≤60,0≤ΨIΨE≤1,KnD≤2000 (defined in the main text). The developed model for βi for attractive Coulomb and image potential interactions

The generation of a secondary aerosol after impact, consisting of smaller droplets at a given velocity and mass flow, is relevant for various applications. Thus far, the investigations and modelling approaches on spray impact are based on extrapolation of the single-droplet impingement or empirical correlations. The validity of the models presented is limited to the given experimental setup and conditions

Bipolar charging and neutralization of aerosol particles with diameter below 10 nm in a circular tube with uniform ion-pair generation have been studied theoretically to determine the conditions required to reach the stationary charge distribution. In order to reach the stationary distribution the initial ion-to-aerosol number concentration ratio, Nin/nin, and the Ninτ product (τ is the mean aerosol

We studied the effect of gravitational sedimentation on the dispersion of 0.5 and 1 micrometer-diameter particle boluses within a two-dimensional symmetric six-generation model of the human acinus. Boluses were introduced at the beginning of a 2-s inspiration immediately followed by a 4-s expiration, in normal gravity (1 G) and in the absence of gravity (0 G). The flow corresponded to a flow rate at

A prototype instrument has been constructed to measure individual airborne particles based on their aerodynamic size and their intrinsic fluorescence at selected excitation and emission wavelength bands. The instrument combines features of an aerodynamic particle sizing device with capabilities similar to those of a liquid flow cytometer. The goal of the instrument is to provide real-time data indicative

We introduce a deep learning method to simulate the chaotic motion of particles trapped in the recirculation zone of a buoyancy-opposed flame. The Lagrangian trajectories of particles in flame were captured using a high-speed camera and subsequently reconstructed in a 3-dimensional cylindrical space. These experimentally determined trajectories were next used to train the two most widely adopted deep

To study the impact of dust aerosol particles through their role as ice nuclei (IN) on the development of cloud microphysics and electrification, as well as on their contribution to the precipitation formation, we used a 1.5D detailed microphysics model to conduct sensitivity analysis of the Cooperative Convective Precipitation Experiment (CCOPE) case on 19 July 1981 in Miles City, Montana, USA. The

The purpose of this study is to develop an experimental methodology with relevant space and time resolutions to track the velocity properties responsible for the resuspension of microparticles during the acceleration stage of a fan start. Microparticles release is investigated over a time period of several seconds, i.e. at short time. This methodology involves velocity signal measurements thanks to

Understanding of the droplet detachment behavior from rough hydrophilic surfaces is important in many biological and industrial applications such as biomedicine, surface coating, and pathogen-laden aerosol resuspension. Due to the partial detachment of the droplet on hydrophilic surfaces, leaving behind some droplet residues, the adhesion behavior is extremely complicated. Here we reveal a new adhesion

As the particulate-matter (PM) emission standards in China become increasingly rigorous (their upper limit has decreased to 10 mg/m3 in the power industry), considerable attention has been paid to PM emissions from coal-fired power plants. However, there is a large amount of water vapour in flue gas from power plants, which poses a great challenge to the measurement of the PM mass concentration via

Accurate assessment and effective mitigation of the impacts of non-volatile Particulate Matter (nvPM) emissions from aircraft turbine engines require a detailed understanding of its morphological properties. This review summarizes the state of knowledge for the key morphological properties of nvPM emitted from aircraft turbine engines, i.e., aggregate structure, primary particle size, aggregate size

This work investigates the effect of focused acoustic field on a stream of polydisperse micro water droplets generated by a nebulizer. The acoustic field is induced by a customized axially stepped-thickness piezoelectric circular cylindrical transducer. Exposure of the droplets to the acoustic field while passing through the transducer improves the relative movement between the air and droplets, which

Soot deposition on combustion chamber walls of a diesel engine is one of the key concerns among diesel engine manufacturers as it affects the durability and wear of the power cylinder components. The deposition of soot on the liner also gets scraped to the crank case and leads to soot in the lubrication oil. In this work, a modeling framework is presented to estimate the deposition of soot on the liner

Because of ethical and practical constraints, there are few experimental studies on the deposition of ultrafine particles (<100 nm; UFPs) in the respiratory tract of children. To address this deficiency, we developed a novel method based on a flow-through chamber bag inhalation system, which is capable of measuring in situ size-resolved and total deposition of ambient UFP in a large number of children

The presence of space charge can cause a non-negligible effect in some electrospray applications, which, however, was ignored in previous numerical studies. In the present study, the formation of the cone-jet in the electrospray process is investigated with considering the space charge effects. The governing equations of fluid flow and electrostatics are coupled in the numerical method. The charge

Black carbon (BC) aerosols were measured using a seven channel Aethalometer at a suburban site of Nanjing, East China from January 2015 to December 2016 to study its temporal variations and quantify the magnitude of BC from fossil fuel (BCff) and biomass burning (BCbb) sources. The mean BC mass concentration was observed to be 2200 ± 1309 ng/m3 at the sampling site during the entire observation period

A detailed population balance model is used to simulate titanium dioxide nanoparticles synthesised in a stagnation flame from titanium tetraisopropoxide (TTIP) precursor. A two-step simulation methodology is employed to apply the detailed particle model as a post-process to flame profiles obtained from a fully coupled simulation with detailed gas-phase chemistry, flow dynamics and a simple particle

A new technique to calibrate the sizing and counting characteristics of single-particle optical particle counters (OPCs) is presented. The method is not limited to a specific material for calibration, rather any material that can be aerosolized may be used for calibration. Examples of aerosols with real and complex refractive indices and spherical and non-spherical shapes are employed to demonstrate

The partitioning of semi-volatile organic compounds (SVOCs) between particle and gas phases is a primary focus in the study of the formation and lifetime of secondary organic aerosols (SOAs). To predict the temporal and spatial distribution of SOAs, it is essential to retrieve the fundamental parameters of SVOCs that govern the distribution of organic compounds between the condensed and gas phases

In recent years, liquefied natural gas (LNG) has become a popular alternative to heavy fuel oils for use in marine engines due to its low cost and increasingly stringent emissions regulations from the International Maritime Organization (IMO). While natural gas (NG) combustion produces substantially less soot than other fossil fuels, its soot emissions are not negligible and have not been morphologically

Despite its potential adverse health effects, black carbon (BC) has not received much attention from the perspective of managing indoor air quality at multi-purpose facilities. In this scenario, real-time measurements of indoor BC were performed in a classroom, in parking lots, and in airplane cabins. Results showed that the average typical indoor BC concentration in a classroom is approximately 1 μg/m³

Researchers studying the biological effects of combustion particles typically rely on suspending particles in de-ionized (DI) water, buffer, and/or media prior to in vitro or in vivo experiments. However, the hydrophobic nature of combustion particles makes it difficult to obtain well-suspended, evenly dispersed mixtures, which also makes it difficult to obtain equivalent dosing and endpoint comparisons

Exhaled breath aerosol (EBA) is an important non-invasive biological medium for detecting exogenous environmental contaminants and endogenous metabolites present in the pulmonary tract. Currently, EBA is typically captured as a constituent of the mainstream clinical tool referred to as exhaled breath condensate (EBC). This article describes a simpler, completely non-invasive method for collecting EBA

This study computationally explores the possibility of focusing charged aerosol nanoparticles using electrostatics, similar to focusing of electrons and ions. A non-dimensional electrostatic focusing parameter χe, defined as the ratio of electrostatic potential energy to the kinetic energy of an aerosol nanoparticle, significantly determines focusing performance. The focusing device considered here

Droplet generation through spray breakup is an unsteady and non-linear process which produces a relatively dense, highly polydisperse aerosol containing non-spherical droplets with sizes spanning several orders of magnitude. Such variability in size and shape can lead to significant sources of error for conventional measurements based on laser scattering. Although direct imaging of droplets can potentially

Laboratory investigations of aerosol physico-chemical properties are usually initiated by spray-drying processes. Morphology of the generated particles may vary largely under different spray-drying conditions, which may further affect the characterization of particle properties. However, only limited data is available on the morphology of nebulized submicron particles, particularly for protein particles

Microwave has been extensively applied to inactivate microorganisms in liquids, food, and surfaces. However, energy efficiency is a limiting factor for the environmental application. The utilization pathway and energy efficiency of the microwave in different media have not been investigated. In this study, the inactivation performance, energy utilization, and bactericidal mechanisms for microwave-irradiated

Specific surface areas of particles produced at small-scale diffusion flame burners and also in pilot and large-scale fires involving complex fuels are reported and compared. Specific surface area SBET is determined by BET (Brunauer-Emmett-Teller) analysis and also according to previously developed approach STEM relying on the primary sphere based on TEM (Tansmission Electron Microscopy) images analysis

Ionization balance and nucleation in the plasma, which is formed in welding fumes from gas metal arc welding, are studied. It is demonstrated, that large number of nuclei causes the replace of volume thermal ionization by ionization via nucleus surface. The equation for change in Gibbs free energy during nucleation should be also replaced. Absence of the easy-ionizable additional agent forces the iron

In this work we present a powerful method to gain insight into the formation of inorganic nanoparticles from the gas phase by combining a high-resolution differential mobility analyzer with a time-of-flight mass spectrometer. Exemplary particles are generated by glowing-wire evaporation from tungsten, tantalum, rhenium, niobium and molybdenum and transferred via a new custom-made interface to the mobility

As a renewable fuel, butanol has a higher energy density than short-chain alcohols, and can be mixed with diesel in any proportion. To analyze the particulate matter emissions of butanol isomer in compression ignition engines, in this paper, the four butanol isomers were blended with diesel (25 vol%) named as n-butanol/diesel, s-butanol/diesel, i-butanol/diesel and t-butanol/diesel. The characteristics

When considering the behaviour of particulate materials in the environment, it is important to consider resuspension, in which deposited particles leave the ground and become airborne. Despite significant study, models of resuspension typically include no treatment of transient phenomena in the period shortly after release. This paper describes the selection, initial implementation and validation of

In this present work, a finite volume scheme for approximating a multidimensional nonlinear agglomeration population balance equation on a regular triangular grid is developed. The finite volume schemes developed in literature are restricted to a rectangular grid [43]. However, the accuracy and efficiency of finite volume scheme can be enhanced by considering triangular grids. The triangular grid is