The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Sheldon K Friedlander - One of the best experts on this subject based on the ideXlab platform.
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nanoparticle aggregate volume determination by Electrical Mobility analysis test of idealized aggregate theory using aerosol particle mass analyzer measurements
Journal of Aerosol Science, 2008Co-Authors: Anshuman A Lall, Weizhi Rong, Lutz Madler, Sheldon K FriedlanderAbstract:Abstract The nanoparticle aggregate volumes are determined from the Mobility diameter using the idealized aggregate (IA) theory proposed by Lall and Friedlander [(2006). On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis: I. Theoretical analysis. Journal of Aerosol Science, 27, 260]. The use of IA theory makes it possible to account for aggregate number and size of primary particles and aggregate orientation in the electric field. The theory is tested using an aerosol particle mass analyzer (APM) which determines particle mass based on particle motion in a centrifugal and Electrical force field. Unlike Electrical Mobility analysis, the APM mass measurements are independent of particle morphology because the centrifugal force is directly proportional to the mass. The aggregate volumes based on IA theory are compared with the aggregate volumes measured by the APM. The comparison is made for iron oxide ( density = 5.7 g / cc ) and carbon ( density = 2 g / cc ) aggregates, both generated by laser ablation. A differential Mobility analyzer (DMA) was used to classify the aggregates corresponding to Mobility diameters of 80, 100, and 120 nm. For each Mobility diameter, the aggregate volume was calculated from IA theory; the primary particle diameter was measured by electron microscopy. The aggregate mass for each Mobility diameter was measured directly by the APM without the use of IA theory. The aggregate volume was determined from the mass measured by the APM and the primary particle density. The agreement between the DMA and APM aggregate volume measurements was good for both materials studied. The results support the application of IA theory. In a further application of IA theory, literature data for DMA–APM measurements of the ultrafine atmospheric aerosol were used to calculate the fraction of aggregates.
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Determination of surface area and volume of nanoparticle aggregates deposited in the human respiratory tract using DMA data
Journal of Aerosol Science, 2007Co-Authors: Chiu-sen Wang, Sheldon K FriedlanderAbstract:A method is proposed for using size distribution data obtained with a differential Mobility analyzer (DMA) to calculate the total surface area and volume of Electrically conducting nanoparticle chain aggregates deposited in the human respiratory tract. The method consists of two steps: (1) the Electrical Mobility diameter of conducting aggregates determined with a DMA is used to calculate the diffusion-equivalent diameter and (2) the theory of idealized aggregates developed by Lall and Friedlander [(2006). On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis: I. Theoretical analysis. Journal of Aerosol Science 37, 260] is applied in calculations for the aggregate surface area and volume. The results of calculations using the volume distribution of a sample of diesel exhaust particles indicate that deposited aggregates have a larger total surface area than do Electrical-Mobility-equivalent spheres, even though the deposited aggregates have a much smaller total volume. The proposed method for calculating diffusion-equivalent diameter from Electrical Mobility diameter is also employed to show that the deposition data reported in literature for diesel exhaust particles and petrol particles agree well when the deposition fractions are plotted as functions of diffusion-equivalent diameter.
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on line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis i theoretical analysis
Journal of Aerosol Science, 2006Co-Authors: Anshuman A Lall, Sheldon K FriedlanderAbstract:Abstract Electrical Mobility analyzers are usually calibrated for spherical particles, and provide number, area and volume distributions for spherical particles. However, these instruments cannot be directly used to obtain the surface area and volume distributions for aggregates. Aggregates are important in technological applications, such as the manufacture of fine powdered materials, and in air pollution and atmospheric sciences. Thus, nanoparticle chain aggregates of low fractal dimension are another important limiting case, in addition to spheres; a method is described which makes it possible to relate aggregate surface area and volume distributions to the Electrical Mobility diameter. This is accomplished by equating the migration velocity of an aggregate to that of a sphere. Particles of equal migration velocities will trace similar paths in the Mobility analyzer and have the same Mobility diameter (neglecting the Brownian diffusive spread). By equating the migration velocities of a sphere and aggregate, the number and size of the primary particles composing the aggregate can be related to the diameter of a sphere with the same migration velocity. The calculation of aggregate surface areas and volumes requires two theoretical “modules”, one for the drag on the aggregates and the other for aggregate charging efficiency. Two modules selected from the literature were used. The results indicate that the surface area distributions of aggregates with random orientation are somewhat over-predicted when calculated directly from the Mobility diameter. However, the volume distributions are greatly over-predicted, up to a factor of ten compared with values based on the Mobility diameter. The affect of aggregate orientation on surface area estimates was also examined.
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On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis: II. Comparison of measurements and theory
Journal of Aerosol Science, 2006Co-Authors: Anshuman A Lall, Weizhi Rong, Martin Seipenbusch, Sheldon K FriedlanderAbstract:Abstract Differential Mobility analyzers (DMAs) are sometimes used to characterize aerosols that contain aggregates of low fractal dimension. However, these instruments are normally calibrated for spherical particles and the calibrations are not directly applicable to aggregates. A method proposed by Lall and Friedlander [(2006). On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis, I: Theoretical analysis. Journal of Aerosol Science , in press] for characterizing ultrafine aggregate number, surface area and volume distributions by Electrical Mobility measurements was tested experimentally. The method is best applied to idealized aggregates composed of uniform primary particles smaller than the mean free path of the gas. It relates the number and size of the primary particles that compose the aggregate to the Mobility diameter of a spherical particle. Aggregate number distributions were obtained by calculations based on aggregate drag and aggregate charging efficiency; surface area and volume were obtained by summing over the primary particles that compose the aggregate. The theory was tested experimentally using silver aggregates generated by an evaporation–condensation method. Primary particle diameter was 18.5 ± 3.5 nm . To obtain distributions with respect to particle volume, aggregates were sintered to form spheres. It was assumed that the aggregate volume does not change upon sintering and coagulation was neglected. Thus the number of aggregates in a given volume range (number distribution, d N / dlog v vs. v ) should not change after sintering. Agreement between aggregate number distribution based on idealized aggregates and the values measured for spheres of sintered aggregates was good. The agreement also indicates that the aggregate volumes based on idealized aggregates were accurate. The aggregate number distribution and volume based on the conventional calibration for spheres were significantly overpredicted. A separate experimental test of the theory was made using literature data for diesel aggregates. Primary particle diameter was 31.9 ± 7.2 nm . Aggregate volumes calculated from theory agreed well with aggregate volumes measured by transmission electron microscope analysis.
Suresh Dhaniyala - One of the best experts on this subject based on the ideXlab platform.
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A multiple charging correction algorithm for scanning Electrical Mobility spectrometer data
Journal of Aerosol Science, 2013Co-Authors: Suresh DhaniyalaAbstract:Abstract Accuracy of particle size distribution measurements from scanning Electrical Mobility spectrometers (SEMS) is critically dependent on the quality of SEMS data inversion. A critical element of SEMS data inversion is the consideration of the charged particle fraction in the sample flow. In particular, when larger, multiply-charged particles are present in the measured aerosol, significant errors in the calculation of size distributions are possible if their contribution is not correctly accounted for. While ignoring the contribution of multiply charged particles may be acceptable when the particles are mostly in the ultrafine size range, a substantial error is possible when a significant fraction of particles are larger than 100 nm. Accurate calculation of size distributions from SEMS data is possible when an inertial impactor is used to eliminate the contribution of multiply-charged particles larger than a cut-size and an iterative multiple-charge correction (MCC) algorithm is used during the data inversion process. The effectiveness of this approach is, however, strongly dependent on the relationship between the aerodynamic and the Electrical Mobility diameters of the particles. Here, we demonstrate the limitations of the existing inversion algorithms and propose an alternative MCC algorithm for size distribution calculation from non-ideal SEMS data. In the proposed approach, the zeroth order singly charged particle size distribution is fit using a Gumbel distribution function, and the resultant fit is used to correct for the multiply-charged contribution to the SEMS data. The effectiveness of the proposed approach is tested for a range of particle size distribution scenarios and validated with experimental data.
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Improved Inversion of Scanning Electrical Mobility Spectrometer Data Using a New Multiscale Expectation Maximization Algorithm
Aerosol Science and Technology, 2013Co-Authors: Praney Dubey, Suresh DhaniyalaAbstract:The accuracy of particle size distributions obtained from scanning Electrical Mobility spectrometer (SEMS) measurements is strongly dependent on the accurate consideration of the instrument characteristics in the formulation of the SEMS problem and the effective inversion of the resulting SEMS equation. The estimation of size distributions from SEMS measurements requires a solution of the discretized form of the Fredholm integral equation of the first kind. The often ill-conditioned nature of the linear inverse problem coupled with the possible presence of measurement noise complicates these calculations. The use of standard inversion approaches, such as nonnegative least squares (NNLS) or regularization-based algorithms, requires SEMS measurements with significant signal-to-noise ratio or some a priori knowledge of the shape of the sampled size distribution. These severe constraints for SEMS measurements can be relaxed with the new multiscale expectation-maximization SEMS inversion method introduced here...
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A novel Electrical-Mobility-based instrument for total number concentration measurements of ultrafine particles
Journal of Aerosol Science, 2009Co-Authors: Manish Ranjan, Suresh DhaniyalaAbstract:Abstract A novel Electrical-Mobility-based technique to measure total particle number concentration over a selected size range is presented. Charged particles are condensed out onto an electrode that is shaped such that the product of its transfer function and the particle charging efficiency is a constant, independent of particle size. The resulting total current is then proportional to the number concentration of the sampled particles over the collected size range. The theoretical approach for the calculation of the electrode shape function is described. The extension of this technique for measurement of higher moments of the particle size distributions over a desired size range is briefly discussed. This concept is used to design a new instrument, called the tailored electrode concentration sensor (TECS). For validation of the theoretical concept, the collection electrode in the TECS instrument is designed for concentration measurements over a size range of 30–90 nm. In the TECS, the collection section is located downstream of an electrostatic precipitator section, where the sampled flow is split into aerosol and sheath flows, similar to the design of the MEAS [Ranjan, M., & Dhaniyala, S., (2007), Theory and design of a new miniature Electrical-Mobility aerosol spectrometer, Journal of Aerosol Science, 38(9), 950–963]. This results in a compact, low pressure drop instrument. Experimental results confirm that the response of the optimally-shaped electrode in the TECS system is only proportional to total number concentration over the selected size range.
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Performance Comparison of Scanning Electrical Mobility Spectrometers
Aerosol Science and Technology, 2007Co-Authors: Jason Rodrigue, Manish Ranjan, Suresh Dhaniyala, Philip K. HopkeAbstract:Scanning Electrical Mobility spectrometers (SEMS) are commonly used for near real-time ultrafine particle size distribution measurements. Analysis of SEMS measurements to calculate particle size distributions requires detailed understanding of instrument characteristics and operation. Varying instrument designs are used in the different commercial SEMS systems, and data analysis with these instruments requires accurate knowledge of their relative performance. In this study, an experimental approach to evaluate and reconcile differences between different SEMS instruments is established. This approach is used to characterize the relative performance of two SEMS systems—TSI's SMPS 3936-L22 and MSP's WPS XP1000—for particle sizes in the range of 20 to 300 nm. In these tests, the instruments were operated under a low flowrate condition with aerosol and sheath air flows of 0.3 and 3 LPM, respectively. Measurements show that the particle sizing characteristics of the instruments are very consistent with each oth...
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Theory and design of a new miniature Electrical-Mobility aerosol spectrometer
Journal of Aerosol Science, 2007Co-Authors: Manish Ranjan, Suresh DhaniyalaAbstract:Theory and design of a new Electrical-Mobility based instrument for measurement of aerosol particle size distributions in real-time is presented. Miniature Electrical aerosal spectrometer (MEAS) has a rectangular cross-section with two main regions: the electrostatic precipitator (ESP) and classifier sections. The ESP section enables charged particle injection into the classifier section in a narrow range of streamlines at the desired location. The injected charged particles are then segregated based on their Electrical Mobility in the classifier section and collected on a series of plates that are connected to electrometers. Real-time particle size distribution measurements can be inferred from the electrometer signal strengths with the knowledge of the instrument transfer function. A theoretical approach is developed to calculate MEAS transfer function considering the non-uniformity in the electric and flow fields inside the instrument, and accounting for the instrument dimensions and its operating conditions. The theoretical predictions of size classification characteristics are seen to compare well with numerical results. The modeling results suggest that an optimal operational domain exists for MEAS.
Anshuman A Lall - One of the best experts on this subject based on the ideXlab platform.
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nanoparticle aggregate volume determination by Electrical Mobility analysis test of idealized aggregate theory using aerosol particle mass analyzer measurements
Journal of Aerosol Science, 2008Co-Authors: Anshuman A Lall, Weizhi Rong, Lutz Madler, Sheldon K FriedlanderAbstract:Abstract The nanoparticle aggregate volumes are determined from the Mobility diameter using the idealized aggregate (IA) theory proposed by Lall and Friedlander [(2006). On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis: I. Theoretical analysis. Journal of Aerosol Science, 27, 260]. The use of IA theory makes it possible to account for aggregate number and size of primary particles and aggregate orientation in the electric field. The theory is tested using an aerosol particle mass analyzer (APM) which determines particle mass based on particle motion in a centrifugal and Electrical force field. Unlike Electrical Mobility analysis, the APM mass measurements are independent of particle morphology because the centrifugal force is directly proportional to the mass. The aggregate volumes based on IA theory are compared with the aggregate volumes measured by the APM. The comparison is made for iron oxide ( density = 5.7 g / cc ) and carbon ( density = 2 g / cc ) aggregates, both generated by laser ablation. A differential Mobility analyzer (DMA) was used to classify the aggregates corresponding to Mobility diameters of 80, 100, and 120 nm. For each Mobility diameter, the aggregate volume was calculated from IA theory; the primary particle diameter was measured by electron microscopy. The aggregate mass for each Mobility diameter was measured directly by the APM without the use of IA theory. The aggregate volume was determined from the mass measured by the APM and the primary particle density. The agreement between the DMA and APM aggregate volume measurements was good for both materials studied. The results support the application of IA theory. In a further application of IA theory, literature data for DMA–APM measurements of the ultrafine atmospheric aerosol were used to calculate the fraction of aggregates.
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on line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis i theoretical analysis
Journal of Aerosol Science, 2006Co-Authors: Anshuman A Lall, Sheldon K FriedlanderAbstract:Abstract Electrical Mobility analyzers are usually calibrated for spherical particles, and provide number, area and volume distributions for spherical particles. However, these instruments cannot be directly used to obtain the surface area and volume distributions for aggregates. Aggregates are important in technological applications, such as the manufacture of fine powdered materials, and in air pollution and atmospheric sciences. Thus, nanoparticle chain aggregates of low fractal dimension are another important limiting case, in addition to spheres; a method is described which makes it possible to relate aggregate surface area and volume distributions to the Electrical Mobility diameter. This is accomplished by equating the migration velocity of an aggregate to that of a sphere. Particles of equal migration velocities will trace similar paths in the Mobility analyzer and have the same Mobility diameter (neglecting the Brownian diffusive spread). By equating the migration velocities of a sphere and aggregate, the number and size of the primary particles composing the aggregate can be related to the diameter of a sphere with the same migration velocity. The calculation of aggregate surface areas and volumes requires two theoretical “modules”, one for the drag on the aggregates and the other for aggregate charging efficiency. Two modules selected from the literature were used. The results indicate that the surface area distributions of aggregates with random orientation are somewhat over-predicted when calculated directly from the Mobility diameter. However, the volume distributions are greatly over-predicted, up to a factor of ten compared with values based on the Mobility diameter. The affect of aggregate orientation on surface area estimates was also examined.
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On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis: II. Comparison of measurements and theory
Journal of Aerosol Science, 2006Co-Authors: Anshuman A Lall, Weizhi Rong, Martin Seipenbusch, Sheldon K FriedlanderAbstract:Abstract Differential Mobility analyzers (DMAs) are sometimes used to characterize aerosols that contain aggregates of low fractal dimension. However, these instruments are normally calibrated for spherical particles and the calibrations are not directly applicable to aggregates. A method proposed by Lall and Friedlander [(2006). On-line measurement of ultrafine aggregate surface area and volume distributions by Electrical Mobility analysis, I: Theoretical analysis. Journal of Aerosol Science , in press] for characterizing ultrafine aggregate number, surface area and volume distributions by Electrical Mobility measurements was tested experimentally. The method is best applied to idealized aggregates composed of uniform primary particles smaller than the mean free path of the gas. It relates the number and size of the primary particles that compose the aggregate to the Mobility diameter of a spherical particle. Aggregate number distributions were obtained by calculations based on aggregate drag and aggregate charging efficiency; surface area and volume were obtained by summing over the primary particles that compose the aggregate. The theory was tested experimentally using silver aggregates generated by an evaporation–condensation method. Primary particle diameter was 18.5 ± 3.5 nm . To obtain distributions with respect to particle volume, aggregates were sintered to form spheres. It was assumed that the aggregate volume does not change upon sintering and coagulation was neglected. Thus the number of aggregates in a given volume range (number distribution, d N / dlog v vs. v ) should not change after sintering. Agreement between aggregate number distribution based on idealized aggregates and the values measured for spheres of sintered aggregates was good. The agreement also indicates that the aggregate volumes based on idealized aggregates were accurate. The aggregate number distribution and volume based on the conventional calibration for spheres were significantly overpredicted. A separate experimental test of the theory was made using literature data for diesel aggregates. Primary particle diameter was 31.9 ± 7.2 nm . Aggregate volumes calculated from theory agreed well with aggregate volumes measured by transmission electron microscope analysis.
Richard C Flagan - One of the best experts on this subject based on the ideXlab platform.
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The nano-scanning Electrical Mobility spectrometer (nSEMS) and its application to size distribution measurements of 1.5–25 nm particles
2021Co-Authors: Weimeng Kong, Huajun Mai, Yuanlong Huang, John H. Seinfeld, Stavros Amanatidis, Changhyuk Kim, Benjamin C. Schulze, Gregory S. Lewis, Susanne V. Hering, Richard C FlaganAbstract:Abstract. Particle size measurement in the low nanometer regime is of great importance to the study of cloud condensation nuclei formation and to better understand aerosol-cloud interaction. Here we present the design, modeling, and experimental characterization of the nano-scanning Electrical Mobility spectrometer (nSEMS), a recently developed instrument that probes particle physical properties in the 1.5–25 nm range. The nSEMS consists of a charge conditioner, a novel differential Mobility analyzer, and a two-stage condensation particle counter (CPC). The charge conditioner employs a soft x-ray bipolar ion source in a compact housing designed to optimize both nanoparticle charging and transmission efficiency. The Mobility analyzer, a radial opposed migration ion and aerosol classifier (ROMIAC), can classify nanometer-sized particles with minimal degradation of its resolution or diffusional losses. The ROMIAC operates on a dual high-voltage supply with fast polarity-switching capability to minimize sensitivity to variations in the chemical nature of the ions used to charge the aerosol. Particles transmitted through the charge conditioner and Mobility analyzer are measured using a two-stage CPC. They are first activated in a fast-mixing diethylene glycol (DEG) stage before being counted by a second detection stage, an ADI MAGICTM water-based CPC. The transfer function of the integrated instrument is derived from both finite-element modeling and experimental characterization. The nSEMS performance has been evaluated during measurement of transient nucleation and growth events in the CLOUD atmospheric chamber at CERN. We show that the nSEMS can provide high time and size resolution measurement of nanoparticles, and can capture the critical aerosol dynamics of newly formed atmospheric particles.
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Diffusional transfer function for the scanning Electrical Mobility spectrometer (SEMS)
Aerosol Science and Technology, 2020Co-Authors: Yuanlong Huang, John H. Seinfeld, Richard C FlaganAbstract:The scanning Electrical Mobility spectrometer (SEMS), or scanning Mobility particle sizer (SMPS), uses the differential Mobility analyzer (DMA) operated in scanning mode to measure particle size di...
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Scanning DMA Data Analysis I. Classification Transfer Function
Aerosol Science and Technology, 2018Co-Authors: Huajun Mai, Richard C FlaganAbstract:The scanning Electrical Mobility spectrometer (SEMS; also known as the scanning Mobility particle sizer, SMPS) enables rapid particle size distribution measurements with a differential Mobility ana...
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An Asymptotic Analysis of Differential Electrical Mobility Classifiers
Aerosol Science and Technology, 2011Co-Authors: Andrew J. Downard, James F. Dama, Richard C FlaganAbstract:An asymptotic analysis of balanced flow operations of differential Mobility analyzers (DMAs) and a new class of instruments that includes opposed migration aerosol classifiers (OMACs) and inclined grid Mobility analyzers (IGMAs) provides new insights into the similarities and differences between the devices. The characteristic scalings of different instruments found from minimal models are shown to relate the resolving powers, dynamic ranges, and efficiencies of most such devices. The resolving powers of all of the instruments in the nondiffusive regime of high voltage classifications, R_(nd), is determined by the ratio of the flow rate of the separation gas (sheath or crossflow) to that of the aerosol. At lowvoltage,when diffusion degrades the classification, the OMAC and the IGMA share an R_(nd) factor advantage in dynamic range of mobilities over the DMA, although the OMAC also suffers greater losses because diffusion immediately deposits particles onto its porous electrodes. On the basis of this analysis, a single master operating diagram is proposed for DMAs, OMACs, and IGMAs. Analysis of this operating diagram and its consequences for the design of differential Electrical Mobility classifiers suggests that OMACs and IGMAs also have advantages over DMAs in design flexibility and miniaturization. Most importantly, OMACs and IGMAs may outperform DMAs for the currently difficult classification of particles with diameters less than 10 nm. On the other hand, DMAs are more amenable to voltage scanning-mode operation to enable accelerated size distribution measurements, whereas it is most convenient to operate OMACs and IGMAs in voltage stepping-mode operation.
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Electrical Mobility measurements of fine-particle formation during chamber studies of atmospheric photochemical reactions
Environmental Science & Technology, 1991Co-Authors: Richard C Flagan, Shih Chen Wang, John H. Seinfeld, Fangdong Yin, G.p. Reischl, W. Winklmayr, Rudolf KarchAbstract:New approaches have been applied to Electrical Mobility measurement of ultrafine aerosol particles in smog chamber studies of secondary aerosol formation. With several Mobility classifiers operating in parallel, rapid new particle formation was followed in the photochemical oxidation of dimethyl disulfide. When foreign particles were present before reaction was initiated, multiple bursts of nucleation and oscillations in the concentrations of 3.4-nm particles were observed. Later experiments used the scanning Electrical Mobility spectrometer to make high-resolution particle size distribution measurements. With this measurement method, the rapid growth of nuclei from their initial appearance at 10-nm size was followed in hydrocarbon/NO_x and hydrocarbon/NO_x/SO_2 reactions. Again, multiple bursts of nucleation were observed in some experiments, and insights were gained into particle growth mechanisms.
Hyunjin Moon - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Particle Morphology on Unipolar Diffusion Charging of Silver Nanowires
Aerosol Science and Technology, 2015Co-Authors: Miso Park, Kihong Park, Hyunjin Moon, Weon Gyu ShinAbstract:We investigated the effect of particle morphology on unipolar charging of nanowires. The average diameters of silver nanowires were 32, 48, and 68 nm. Particle Electrical capacitance is an important parameter that determines the mean charge per particle in a continuum regime. We predicted that a nanowire has larger Electrical capacitance than a sphere, and for a nanowire, the Electrical capacitance increases as its diameter decreases. The mean charge per nanowire particle was calculated with the Electrical capacitance obtained from theoretical analysis as a function of Electrical Mobility diameter. The mean charge per particle was measured for polystyrene latex particles with an Electrical Mobility diameter of 100–300 nm, and silver nanowires with an Electrical Mobility diameter of 200–400 nm. For a given Electrical Mobility diameter, the mean charge per particle of a nanowire in theoretical analysis and experiments was larger than that of a sphere, and it increased as the diameter of the nanowire decreas...
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Electrical Mobility of silver nanowires in transition and continuum regimes
Journal of Aerosol Science, 2014Co-Authors: Miso Park, Weon Gyu Shin, Hyunjin MoonAbstract:Abstract In this work, the flow regime behavior of silver nanowires with cylindrical morphology where the diameter is close to the mean free path and length is larger than the mean free path is investigated. The theory for a cylindrical particle by Li et al. (2012) is compared with experimental results of silver nanowires with known shape determined by SEM images for the Mobility sizes of d m =200, 300, 400, 600 nm. The nanowires had the following dimensions: (1) average diameter d f =46.5 nm and average lengths L f =902.0 nm ( d m =200 nm), L f =1189.5 nm ( d m =300 nm), L f =1515.9 nm ( d m =400 nm), (2) average diameter d f =75.0 nm and average lengths L f =617.5 nm ( d m =200 nm), L f =1190.9 nm ( d m =400 nm), L f =2042.7 nm ( d m =600 nm). We found that the flow regime of a nanowire with a diameter as much as or larger than the mean free path of gas moves from the transition regime to the continuum regime as the Mobility size becomes larger. When the Electrical Mobility diameter is relatively small, the flow regime is controlled by the diameter of a nanowire, which is the smallest dimension of nanowires. However, as the Electrical Mobility diameter of silver nanowires becomes larger, the flow regime is transitioned to the continuum regime, i.e., controlled by the length, not the diameter, of silver nanowires. In addition, the dynamic shape factor of a randomly aligned and fully aligned nanowire with cylindrical morphology in the continuum regime is predicted as a function of Mobility diameter and the result shows that for a given Mobility diameter the dynamic shape factor of a fully aligned nanowire is smaller than that of a randomly aligned nanowire.