Characterising the silver particle generator; a pathway towards standardising silver aerosol generation

Hammer, Tobias; Irwin, M.; Swanson, Jacob; Berger, V.; Sonkamble, U.; Boies, Adam M.; Schulz, Hartwig; Vasilatou, Konstantina

doi:10.1016/j.jaerosci.2022.105978

Cited by 8 publications

(6 citation statements)

References 36 publications

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“…The reason of this 15% correction was not investigated in detail, but is well within expected differences between SMPS and CPCs [44,45]. The same figure plots (dotted line) the expected ratio measuring polydisperse aerosol, based on the monodisperse counting efficiencies found in the literature for the specific CPC model [27]. Small symbols are measurements in photometric mode, while big symbols in single counting mode.…”

Section: Discussionsupporting

confidence: 63%

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Assessment of two condensation particle counters (CPCs) in photometric mode for high concentration exhaust emission measurements

Giechaskiel¹,

Melas²,

Mamakos³

2023

Combustion Engines

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Condensation particle counters (CPCs) use light scattering to count particles after they have grown to micron size in a supersaturated environment. In single counting mode each particle is counted depending on whether the scattered light exceeds a threshold value or not. In photometric mode the total scattered light is converted in particle number concentration. While for laboratory grade particle number systems, CPCs are allowed to operate only in single counting mode, there is no such requirements for portable emissions measurements systems (PEMS) for real-driving emissions (RDE) testing or for instruments for periodic technical inspection (PTI) of vehicles. In this study two CPCs of the same model were assessed in single counting and photometric modes with silver and graphite particles with sizes ranging from 10 nm to 100 nm. The results showed that the concentration was measured accurately enough for particles in the 25 nm to 50 nm size range, but was underestimated and overestimated for smaller and larger particles, respectively. The key message is that the photometric mode should be avoided or calibrated in function of concentration and particle size.

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Section: Discussionsupporting

confidence: 63%

“…Two identical butanol CPCs (model 3752, TSI) with 50% efficiency at 4 nm were measuring the particle number concentration [26,27]. The CPCs were used with 1.5 dm 3 /min flowrate.…”

Section: Condensation Particle Counters (Cpcs) Model 3752mentioning

confidence: 99%

Assessment of two condensation particle counters (CPCs) in photometric mode for high concentration exhaust emission measurements

Giechaskiel¹,

Melas²,

Mamakos³

2023

Combustion Engines

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“…The silver particle generator (SPG, Catalytic Instruments GmbH & Co.KG, Rosenheim, Germany) produces silver particles via evaporation-condensation in a vertical tube furnace [48]. The silver containing tube is heated at 1000-1100 • C and a 2 L/min carrier gas flow (particle free air in our tests) transports and cools the silver nuclei to the main flow tube, where they are optionally diluted with a flow of 0-20 L/min.…”

Section: Silver Generatormentioning

confidence: 99%

“…The methods that are used to achieve supersaturation and particle growth are adiabatic expansion of the aerosol-vapor mixture, conductive cooling, or mixing of cool and warm saturated air [56]. The CPC of this study was the butanol-based model 3752 from TSI with 50% efficiency at 4 nm [48,57]. A flow rate of 1.5 L/min was selected.…”

Section: Cpcmentioning

confidence: 99%

Comparison of Particle Sizers and Counters with Soot-like, Salt, and Silver Particles

Giechaskiel

Melas

2022

Atmosphere

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Vehicle emission regulations in Europe and many Asian countries include a particle number limit. The number concentration is measured, typically, with condensation particle counters (CPCs). For research purposes, the size distributions provide useful information. Scanning mobility particle sizers (SMPSs) accurately provide the size distribution but are not suitable for transient aerosol. Engine (fast) exhaust particle sizers (EEPSs) cover this gap, but with less accuracy. Fast size distribution instruments are commonly used in the research and development of engines. In the last few years, instrument algorithms have been improved, but studies assessing the improvements are limited, in particular in their lower size range, around 10–20 nm, and for soot-like aerosol. In this paper, we compared the three instruments using salt, silver, diffusion flame soot (CAST), and spark discharge graphite particles. Moreover, vehicle exhaust number concentration measurements with EEPSs over a seven-year period were presented. In terms of particle concentration, EEPS overestimated, on average, 25% compared to CPC, in agreement with previous studies. Its accuracy for mean particle size determination was better than 5 nm compared to SMPS. The agreement between the instruments was satisfactory but the uncertainty increased at low concentrations and larger particle sizes, showing that there is still room for further improvements. Experimental challenges, such as low concentration levels of modern vehicles, losses in the diluters, use of photometric mode by the CPCs, and the material impact, are also discussed.

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“…The silver nanoparticle generator has a glass test tube arrangement as depicted in Figure 10 , used to produce silver nanoparticles in the laboratory [ 63 ]. Nitrogen gas is passed onto a small piece of silver (Ag) placed at the bottom of the glass test tube.…”

Section: Methodsmentioning

confidence: 99%

Towards Portable MEMS Oscillators for Sensing Nanoparticles

Chellasivalingam

Zielinski

Whitney

et al. 2022

Sensors

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This paper reports on the design, and implementation of piezoelectric-on-silicon MEMS resonators installed within a portable experimental setup for sensing nanoparticles in a laboratory environment. MEMS oscillators with a center frequency of approximately 5.999 MHz are employed for sensing 50 nm size-selected silver nanoparticles generated in the laboratory. The same experimental setup is then assembled to sense indoor particles that are present in the laboratory environment. The challenges associated with particle deposition as a result of assembling the portable experimental setup is highlighted. Furthermore, the MEMS oscillators demonstrate that the total mass of silver nanoparticles deposited onto the MEMS resonator surface using the inertial impaction technique-based experimental setup is approximately 7.993 nanograms. The total indoor particle mass accumulated on the MEMS resonator surface is estimated to be approximately 1.732 nanograms and 26.9 picograms for two different runs. The frequency resolution of the MEMS oscillator is estimated to be approximately 32 ppb and, consequently, the minimum detectable particle mass is approximately 60 femtograms for a 9.2 s integration time.

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Characterising the silver particle generator; a pathway towards standardising silver aerosol generation

Cited by 8 publications

References 36 publications

Assessment of two condensation particle counters (CPCs) in photometric mode for high concentration exhaust emission measurements

Assessment of two condensation particle counters (CPCs) in photometric mode for high concentration exhaust emission measurements

Comparison of Particle Sizers and Counters with Soot-like, Salt, and Silver Particles

Towards Portable MEMS Oscillators for Sensing Nanoparticles

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