scholarly journals Optical-Trapping Laser Techniques for Characterizing Airborne Aerosol Particles and Its Application in Chemical Aerosol Study

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 466
Author(s):  
Aimable Kalume ◽  
Chuji Wang ◽  
Yongle Pan
Keyword(s):  
Light Scattering ◽  
High Speed ◽  
Optical Trapping ◽  
Aerosol Particles ◽  
Particle Interaction ◽  
Raman Laser ◽  
General Description ◽  
Sample Collection ◽  
Laser Technologies ◽  
Laser Induced Breakdown

We present a broad assessment on the studies of optically-trapped single airborne aerosol particles, particularly chemical aerosol particles, using laser technologies. To date, extensive works have been conducted on ensembles of aerosols as well as on their analogous bulk samples, and a decent general description of airborne particles has been drawn and accepted. However, substantial discrepancies between observed and expected aerosols behavior have been reported. To fill this gap, single-particle investigation has proved to be a unique intersection leading to a clear representation of microproperties and size-dependent comportment affecting the overall aerosol behavior, under various environmental conditions. In order to achieve this objective, optical-trapping technologies allow holding and manipulating a single aerosol particle, while offering significant advantages such as contactless handling, free from sample collection and preparation, prevention of contamination, versatility to any type of aerosol, and flexibility to accommodation of various analytical systems. We review spectroscopic methods that are based on the light-particle interaction, including elastic light scattering, light absorption (cavity ring-down and photoacoustic spectroscopies), inelastic light scattering and emission (Raman, laser-induced breakdown, and laser-induced fluorescence spectroscopies), and digital holography. Laser technologies offer several benefits such as high speed, high selectivity, high accuracy, and the ability to perform in real-time, in situ. This review, in particular, discusses each method, highlights the advantages and limitations, early breakthroughs, and recent progresses that have contributed to a better understanding of single particles and particle ensembles in general.

High-Speed Aerosol Flow Through Micro-Nozzles for Direct-Write Processes

2013 ◽  
Author(s):  
Justin M. Hoey ◽  
Sourin Bhattacharya ◽  
Artur Lutfurakhmanov ◽  
Michael Robinson ◽  
Orven F. Swenson ◽  
...  
Keyword(s):  
High Speed ◽  
Aerosol Particles ◽  
Particle Interaction ◽  
Direct Write ◽  
Particle Rotation ◽  
High Speed Flow ◽  
Magnus Force ◽  
Aerosol Flow ◽  
Speed Flow ◽  
Flow Through

Aerosol direct-write printing for mesoscale features has been commercially available since around 2002 from Optomec®. We have developed variances to this process first in Collimated Aerosol Beam-Direct Write (CAB-DW) for printing sub-10 μm features and in Micro Cold Spray for printing with solid metallic aerosols. These deposition tools offer extensive uses, but are still limited in certain applications by either line widths or the amount of overspray. Modeling of aerosol flow through micro-nozzles used in these applications yields a greater understanding of the focusing of these aerosol particles, and may provide a vehicle for new nozzle designs which will further enhance these tools. Recent modeling applied both Stokes and Saffman force to the aerosol particles. Under certain conditions particle rotation and Magnus force may also be necessary to accurately predict the aerosol particles. In this paper we will present our recent results of high-speed flow of 1–10 μm diameter aerosol particles through micro-nozzles in which the model includes all three forces (Stokes, Saffman, Magnus) of fluid-particle interaction, and a comparison of these results to experiments.

Aerosol Flow Through a Micro-Capillary

2009 ◽  
Author(s):  
Iskander S. Akhatov ◽  
Justin M. Hoey ◽  
Drew Thompson ◽  
Artur Lutfurakhmanov ◽  
Zakaria Mahmud ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Aerosol Particles ◽  
Particle Interaction ◽  
Direct Write ◽  
Center Line ◽  
Aerosol Flow ◽  
Aerodynamic Focusing ◽  
Ink Jet ◽  
Micron Size ◽  
Flow Through

A combined theoretical/experimental study of micron size aerosol flows through micro-capillaries of diameter about 100 μm and length about 1 cm is presented. It is shown that under proper conditions at a relatively high velocity of about 100 m/s such an aerosol flow reveals a new manifestation of microfluidics: the Saffman force acting on aerosol particles in gas flowing through a micro-capillary becomes significant thereby causing noticeable migration of particles toward the center line of the capillary. This finding opens up new opportunities for aerosol focusing, which is in stark contrast to the classical aerodynamic focusing methodologies where only particle inertia and the Stokes force of gas-particle interaction are typically used to control particle trajectories. A mathematical model for aerosol flow through a micro-capillary accounting for complicated interactions between particles and carrier gas is presented. This model describes the experimental observables obtained via shadowgraphy for aerosol beams exiting micro-capillaries. It is further shown that it is possible to design a micro-capillary system capable of generating a Collimated Aerosol Beam (CAB) in which aerosol particles stay very close to a capillary center line. The performance of such a CAB system for direct-write fabrication on a substrate is demonstrated. The lines deposited by CAB for direct-write fabrication are shown to exhibit widths of less than 5 μm — superior to ink-jet. Materials deposition based upon directed aerosol flow has the potential of finding application in the fields of flexible electronics, sensors, and solar cells. In this paper, the genesis of a new materials deposition method termed Collimated Aerosol Beam Direct-Write (CAB-DW) is discussed.

scholarly journals In situ damage assessment using synchrotron X-rays in materials loaded by a Hopkinson bar

2014 ◽  
Vol 372 (2015) ◽  
pp. 20130191 ◽  
Author(s):  
Weinong W. Chen ◽  
Matthew C. Hudspeth ◽  
Ben Claus ◽  
Niranjan D. Parab ◽  
John T. Black ◽  
...  
Keyword(s):  
High Speed ◽  
Particle Interaction ◽  
Tensile Failure ◽  
High Rate ◽  
X Rays ◽  
Contrast Imaging ◽  
X Ray ◽  
Damage Initiation ◽  
Dynamic Experiments

Split Hopkinson or Kolsky bars are common high-rate characterization tools for dynamic mechanical behaviour of materials. Stress–strain responses averaged over specimen volume are obtained as a function of strain rate. Specimen deformation histories can be monitored by high-speed imaging on the surface. It has not been possible to track the damage initiation and evolution during the dynamic deformation inside specimens except for a few transparent materials. In this study, we integrated Hopkinson compression/tension bars with high-speed X-ray imaging capabilities. The damage history in a dynamically deforming specimen was monitored in situ using synchrotron radiation via X-ray phase contrast imaging. The effectiveness of the novel union between these two powerful techniques, which opens a new angle for data acquisition in dynamic experiments, is demonstrated by a series of dynamic experiments on a variety of material systems, including particle interaction in granular materials, glass impact cracking, single crystal silicon tensile failure and ligament–bone junction damage.

scholarly journals ASSESSMENT OF ECOLOGICAL STATE OF THE VELIKAYA RIVER DELTA BASED ON HYDROCHEMICAL INDICATORS AND STRUCTURE OF PHYTOPLANKTON

2017 ◽  
Vol 1 ◽  
pp. 82
Author(s):  
Tatiana Drozdenko ◽  
Sergei Mikhalap ◽  
Larisa Nikolskaya ◽  
Anna Chernova
Keyword(s):  
Water Quality ◽  
High Speed ◽  
Shannon Index ◽  
Freshwater Ecosystems ◽  
River Delta ◽  
Ecosystem Dynamics ◽  
Polluted Water ◽  
Ecological State ◽  
Sample Collection ◽  
Wide Range

The basis of the existence of freshwater ecosystems is phytoplankton, which produces most of the primary biological production, participates in repair processes and provides a wide range of ecosystem services. The short life cycle and high speed metabolism of microalgae make them ideal objects for ecological monitoring. The aim of the present study is to research the ecological state of the Velikaya river delta based on the species composition of phytoplankton community and some hydrochemical parameters. The sample collection for phytoplankton study and physicochemical measurements was carried out in summer 2016 at five stations representing different ecological locations of the Velikaya river delta. One hundred sixty five species taxa of microalgae belonging to 8 phylums were identified during the research: Bacillariophyta (37%), Chlorophyta (33.9%), Cyanophyta/Cyanobacteria (9.7%), Chrysophyta (6.1%), Euglenophyta (6.1%), Cryptophyta (3%), Dinophyta (3%), Xanthophyta (1.2%). The values of Shannon index indicate the average complexity of the microalgae communities structure. Values of Margalef index characterize the Velikaya river delta as an area of high species richness. Compared to the previous studies, a significant increase in the level of information diversity is observed, indicating an increase in the number of possible flows of substance and energy in the ecosystem. Dynamics of biogen substances in the water shows a slight increase of their concentrations. Ecological and geographical analysis proves that absolute dominance of cosmopolitan freshwater forms is typical for the algoflora of the Velikaya river delta. In relation to the pH-reaction inhabitants of neutral and slightly alkaline water dominate. Pantle–Buck saprobity index is applied for water quality assessment, which shows beta-mesosaprobic water quality in the ecosystem. Thus, the water of the Velikaya river delta could be referred to the category of moderately polluted water (class II of water quality). This is confirmed by the data of hydrochemical analysis.

Equivalence of Light Scattering by One Internal-Mixed Model for Aerosol Particles

2012 ◽  
Vol 32 (6) ◽  
pp. 0629001 ◽  
Author(s):  
张小林 Zhang Xiaolin ◽  
黄印博 Huang Yinbo ◽  
饶瑞中 Rao Ruizhong
Keyword(s):  
Light Scattering ◽  
Mixed Model ◽  
Aerosol Particles

scholarly journals A European aerosol phenomenology-6: Scattering properties of atmospheric aerosol particles from 28 ACTRIS sites

2017 ◽  
Author(s):  
Marco Pandolfi ◽  
Lucas Alados-Arboledas ◽  
Andrés Alastuey ◽  
Marcos Andrade ◽  
Begoña Artiñano ◽  
...  
Keyword(s):  
Light Scattering ◽  
Eastern Europe ◽  
Atmospheric Aerosol ◽  
Central And Eastern Europe ◽  
Aerosol Particles ◽  
Accumulation Mode ◽  
Annual Variability ◽  
Baltic Countries ◽  
Atmospheric Aerosol Particles ◽  
Fine Mode

Abstract. This paper presents the light scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). A large range of ssp was observed across the network. Low ssp values were on average measured in Nordic and Baltic countries and in Western Europe whereas the highest σsp were measured at regional sites in eastern and central Europe. In these regional areas the SAE was also high indicating the predominance of fine-mode particles. On average, the SAE was lower in the Nordic and Baltic, western and southern countries suggesting a lower fraction of fine-mode particle compared to central and eastern Europe. An increasing gradient of ssp was observed when moving from mountain to regional and to urban sites. Conversely, the mass-independent SAE and g parameters did not show the same gradient. At all sites, both SAE and g varied greatly with aerosol particle loading. The lowest values of g were always observed under low ssp indicating a larger contribution from particles in the smaller accumulation mode. Then, g steeply increased with increasing ssp indicating a progressive shift of the particle size distribution toward the larger end of the accumulation mode. Under periods of high particle mass concentrations, the variation of g was less pronounced whereas the SAE increased or decreased suggesting changes mostly in the coarse aerosol particles mode rather than in the fine mode. The station placement seemed to be the main parameter affecting the intra-annual variability. At mountain sites, higher σsp was measured in summer mainly because of the enhanced boundary layer influence. Conversely, less horizontal and vertical dispersion in winter led to higher σsp at all low altitude sites in central and eastern Europe compared to summer. On average, these sites also showed SAE maxima in summer (and correspondingly g minima). Large intra-annual variability of SAE and g was observed also at Nordic and Baltic countries due to seasonal-dependent transport of different air masses to these remote sites. Statistically significant decreasing trends of σsp were observed at 5 out of 13 stations included in trend analyses. The total reductions of ssp were consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe.

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