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 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).

Phosphate biogeochemical barrier for uranium in situ immobilization in an aquifer nearby sludge repository

2021 ◽  
Author(s):  
Grigory Artemiev ◽  
Alexey Safonov ◽  
Nadezhda Popova
Keyword(s):  
Essential Elements ◽  
Ion Concentration ◽  
Soluble Form ◽  
High Concentration ◽  
Rapid Reduction ◽  
Near Surface ◽  
Nitrate Ions ◽  
Uranium Migration ◽  
Storage Facilities

<p>Uranium migration in the oxidized environment of near-surface groundwater is a typical problem of many radiochemical, ore mining and ore processing enterprises that have sludge storage facilities on their territory. Uranium migration, as a rule, occurs against a high salt background due to the composition of the sludge: primarily, nitrate and sulfate anions and calcium cations. One of the ways to prevent the uranium pollution is geochemical or engineering barriers. For uranium immobilization, it is necessary to create conditions for its reduction to a slightly soluble form of uraninite and further mineralization, for example, in the phosphate form. An important factor contributing to the rapid reduction of uranium is a in the redox potential decreasing and the removal of nitrate ions, which can be achieved through the activation of microflora. It should be added that phosphate itself is one of the essential elements for the development of microflora. This work was carried out in relation to the upper aquifer (7-12 m) near the sludge storage facilities of ChMZ, which is engaged in uranium processing and enrichment. One of the problems of this aquifer, in addition to the high concentration of nitrate ions (up to 15 g / l), is the high velocity of formation waters.<br>In laboratory conditions, the compositions of injection solutions were selected containing sources of organic matter to stimulate the microbiota development and phosphates for uranium mineralization. When developing the injection composition, special attention was paid to assessing the formation of calcite deposits in aquifer conditions to partially reduce the filtration parameters of the horizon and reduce the rate of movement of formation waters. This must be achieved to ensure the possibility of long-term deposition of uranium and removal of nitrate. The composition of the optimal solution was selected and in a series of model experiments the mineral phases containing the lowest hydrated form of the uranium-containing phosphate mineral meta-otenite were obtained.<br>In situ mineral phosphate barrier Formation field tests were carried out in water horizon conditions in a volume of 100m3 by injection of an organic and phosphates mixture. As a result, at the first stage of field work, a significant decreasing nitrate ion concentration, and reducing conditions formation coupled with the dissolved uranium concentration of decreasing were noted.</p>

CPC and SMPS Systems of Monitoring Airborne Nanoparticles-Theory and Experiment

2011 ◽  
Vol 101-102 ◽  
pp. 60-66
Author(s):  
Yi Jui Chiu ◽  
Khai Shoon Leong ◽  
Luh Maan Chang
Keyword(s):  
Experimental Results ◽  
Nano Particles ◽  
Particle Counter ◽  
Condensation Particle Counter ◽  
New Device ◽  
Advantages And Disadvantages ◽  
Mean Diameter ◽  
Airborne Nanoparticles ◽  
Theory And Experiment

The purpose of this paper is to assess technologies used in the monitoring of nano-particles that are available commercially and under research. The goal of the assessment is to propose a new device based on the technologies assessed. The assessment is performed based on information obtained from literatures review of articles and brochures, and from communications with representatives of the manufacturers of the counters. Two types of nano-particles counters were assessed; counters that are currently commercially available are the condensation particle counter (CPC), the scanning mobility particle spectrometer (SMPS). A description of how each counter works is given, and the advantages and disadvantages are highlighted. Experimental results showed that the performance of capillary had been installed and cleaned. The SMPS mean diameter fell within the range of the NIST standard. The sample offered well distribution in 300 and 400 nm.

Pressure-dependent efficiency of a condensation particle counter operated with FC-43 as working fluid

2005 ◽  
Vol 36 (11) ◽  
pp. 1322-1337 ◽  
Author(s):  
M. Hermann ◽  
S. Adler ◽  
R. Caldow ◽  
F. Stratmann ◽  
A. Wiedensohler
Keyword(s):  
Working Fluid ◽  
Particle Counter ◽  
Condensation Particle Counter

Characterization of a Modified Expansion Condensation Particle Counter for Detection of Nanometer-Sized Particles

2009 ◽  
Vol 43 (8) ◽  
pp. 767-780 ◽  
Author(s):  
Hossein Saghafifar ◽  
Andreas Kürten ◽  
Joachim Curtius ◽  
Sarah-Lena von der Weiden ◽  
Smaeyl Hassanzadeh ◽  
...  
Keyword(s):  
Particle Counter ◽  
Condensation Particle Counter
Sign in / Sign up

Export Citation Format

Share Document