scholarly journals Microelectromechanical-system-based condensation particle counter for real-time monitoring of airborne ultrafine particles

2019 ◽  
Vol 12 (10) ◽  
pp. 5335-5345
Author(s):  
Seong-Jae Yoo ◽  
Hong-Beom Kwon ◽  
Ui-Seon Hong ◽  
Dong-Hyun Kang ◽  
Sang-Myun Lee ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Three Dimensional ◽  
Essential Elements ◽  
Number Concentration ◽  
Scattering Method ◽  
Air Filtration ◽  
Particle Counter ◽  
Microelectromechanical System ◽  
Power Efficient ◽  
Condensation Particle Counter

Abstract. We present a portable, inexpensive, and accurate microelectromechanical-system-based (MEMS-based) condensation particle counter (CPC) for sensitive and precise monitoring of airborne ultrafine particles (UFPs) at a point of interest. A MEMS-based CPC consists of two main parts: a MEMS-based condensation chip that grows UFPs to micro-sized droplets and a miniature optical particle counter (OPC) that counts single grown droplets with the light scattering method. A conventional conductive cooling-type CPC is miniaturized through MEMS technology and three-dimensional (3-D) printing techniques; the essential elements for growing droplets are integrated on a single glass slide. Our system is much more compact (75 mm × 130 mm × 50 mm), lightweight (205 g), and power-efficient (2.7 W) than commercial CPCs. In quantitative experiments, the results indicated that our system could detect UFPs with a diameter of 12.9 nm by growing them to micro-sized (3.1 µm) droplets. Our system measured the UFP number concentration with high accuracy (mean difference within 4.1 %), and the number concentration range for which our system can count single particles is 7.99–6850 cm−3. Thus, our system has the potential to be used for UFP monitoring in various environments (e.g., as an air filtration system, in high-precision industries utilizing clean rooms, and in indoor and outdoor atmospheres).

scholarly journals MEMS-based condensation particle counter for real-time monitoring of airborne ultrafine particles at a point of interest

2019 ◽  
Author(s):  
Seong-Jae Yoo ◽  
Hong-Beom Kwon ◽  
Ui-Seon Hong ◽  
Dong-Hyun Kang ◽  
Sang-Myu Lee ◽  
...  
Keyword(s):  
Ultrafine Particles ◽  
Essential Elements ◽  
Scattering Method ◽  
Air Filtration ◽  
High Concentration ◽  
Particle Counter ◽  
Power Efficient ◽  
Condensation Particle Counter ◽  
Point Of Interest ◽  
Mems Technology

Abstract. We present a microelectromechanical system (MEMS)-based condensation particle counter (CPC) for sensitive and precise monitoring of airborne ultrafine particles (UFPs) at a point of interest that is portable, inexpensive, and accurate. The proposed system consists of two main parts: a MEMS-based condensation chip that grows UFPs to micro-sized droplets and a miniature optical particle counter (OPC) that singly counts grown droplets with the light scattering method. A conventional conductive cooling–type CPC is miniaturized through MEMS technology and the 3D printing technique, and the essential elements for growing droplets are integrated on a single glass slide. The proposed system is much more compact (75 mm × 130 mm × 50 mm), lightweight (205 g), and power-efficient (2.7 W) than commercial CPCs. In quantitative experiments, the results indicated that the proposed system can detect UFPs as small as 13.4 nm by growing them to micro-sized (3.16 µm) droplets. The proposed system measured the UFP number concentration with high accuracy (deviation within 4.1 %), and its detectable concentration range of 7.99–7200 N cm−3. Thus, the proposed system can potentially be used for UFP monitoring in both low-concentration (e.g., air filtration system, high-precision industries utilizing cleanrooms) and high-concentration (e.g., indoor/outdoor atmospheres) environments.

scholarly journals Impact on Ultrafine Particles Concentration and Turbulent Fluxes of SARS-CoV-2 Lockdown in a Suburban Area in Italy

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 407
Author(s):  
Antonio Donateo ◽  
Adelaide Dinoi ◽  
Gianluca Pappaccogli
Keyword(s):  
Ultrafine Particles ◽  
Particle Number ◽  
Ultrafine Particle ◽  
Turbulent Fluxes ◽  
Number Concentration ◽  
Suburban Area ◽  
Observation Site ◽  
Meteorological Forcing ◽  
Restrictive Measures ◽  
Measurement Area

In order to slow the spread of SARS-CoV-2, governments have implemented several restrictive measures (lockdown, stay-in-place, and quarantine policies). These provisions have drastically changed the routines of residents, altering environmental conditions in the affected areas. In this context, our work analyzes the effects of the reduced emissions during the COVID-19 period on the ultrafine particles number concentration and their turbulent fluxes in a suburban area. COVID-19 restrictions did not significantly reduce anthropogenic related PM10 and PM2.5 levels, with an equal decrement of about 14%. The ultrafine particle number concentration during the lockdown period decreased by 64% in our measurement area, essentially due to the lower traffic activity. The effect of the restriction measures and the reduction of vehicles traffic was predominant in reducing concentration rather than meteorological forcing. During the lockdown in 2020, a decrease of 61% in ultrafine particle positive fluxes can be observed. At the same time, negative fluxes decreased by 59% and our observation site behaved, essentially, as a sink of ultrafine particles. Due to this behavior, we can conclude that the principal particle sources during the lockdown were far away from the measurement site.

scholarly journals Heritage Artefacts in the COVID-19 Era: The Aura and Authenticity of 3D Models

2021 ◽  
Vol 7 (1) ◽  
pp. 519-539
Author(s):  
Thiago Minete Cardozo ◽  
Costas Papadopoulos
Keyword(s):  
User Experience ◽  
Three Dimensional ◽  
3D Models ◽  
Essential Elements ◽  
The Other ◽  
Social Distancing ◽  
The Public ◽  
Affective Experiences ◽  
The One ◽  
Digital Engagement

Abstract Museums have been increasingly investing in their digital presence. This became more pressing during the COVID-19 pandemic since heritage institutions had, on the one hand, to temporarily close their doors to visitors while, on the other, find ways to communicate their collections to the public. Virtual tours, revamped websites, and 3D models of cultural artefacts were only a few of the means that museums devised to create alternative ways of digital engagement and counteract the physical and social distancing measures. Although 3D models and collections provide novel ways to interact, visualise, and comprehend the materiality and sensoriality of physical objects, their mediation in digital forms misses essential elements that contribute to (virtual) visitor/user experience. This article explores three-dimensional digitisations of museum artefacts, particularly problematising their aura and authenticity in comparison to their physical counterparts. Building on several studies that have problematised these two concepts, this article establishes an exploratory framework aimed at evaluating the experience of aura and authenticity in 3D digitisations. This exploration allowed us to conclude that even though some aspects of aura and authenticity are intrinsically related to the physicality and materiality of the original, 3D models can still manifest aura and authenticity, as long as a series of parameters, including multimodal contextualisation, interactivity, and affective experiences are facilitated.

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