Добірка наукової літератури з теми "Aerosol particles separation"
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Статті в журналах з теми "Aerosol particles separation":
1
Córdoba-Jabonero, Carmen, Michaël Sicard, Albert Ansmann, Ana del Águila, and Holger Baars. "Vertical separation of the atmospheric aerosol components by using poliphon retrieval in polarized micro pulse lidar (P-MPL) measurements: case studies of specific climate-relevant aerosol types." EPJ Web of Conferences 176 (2018): 05041. http://dx.doi.org/10.1051/epjconf/201817605041.
Анотація:
POLIPHON (POlarization-LIdar PHOtometer Networking) retrieval consists in the vertical separation of two/three particle components in aerosol mixtures, highlighting their relative contributions in terms of the optical properties and mass concentrations. This method is based on the specific particle linear depolarization ratio given for different types of aerosols, and is applied to the new polarized Micro-Pulse Lidar (P-MPL). Case studies of specific climate-relevant aerosols (dust particles, fire smoke, and pollen aerosols, including a clean case as reference) observed over Barcelona (Spain) are presented in order to evaluate firstly the potential of P-MPLs measurements in combination with POLIPHON for retrieving the vertical separation of those particle components forming aerosol mixtures and their properties.
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Kirsch, H., and A. Schmidt-Ott. "Material dependent separation of aerosol particles." Journal of Aerosol Science 29 (September 1998): S445—S446. http://dx.doi.org/10.1016/s0021-8502(98)00639-9.
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Drozd, G. T., J. L. Woo та V. F. McNeill. "Self-limited uptake of α-pinene-oxide to acidic aerosol: the effects of liquid-liquid phase separation and implications for the formation of secondary organic aerosol and organosulfates from epoxides". Atmospheric Chemistry and Physics Discussions 13, № 3 (18 березня 2013): 7151–74. http://dx.doi.org/10.5194/acpd-13-7151-2013.
Анотація:
Abstract. The reactive uptake of α-pinene oxide (αPO) to acidic sulfate aerosol was studied under humid conditions in order to gain insight into the effects of liquid-liquid phase separation on aerosol heterogeneous chemistry and further elucidate the formation of secondary organic aerosol and organosulfates from epoxides. A continuous flow environmental chamber was used to monitor changes in diameter of monodisperse, deliquesced, acidic sulfate particles exposed to αPO at 30 and 50% RH. In order to induce phase separation and probe potential limits to particle growth from acidic uptake, αPO was introduced over a wide range of concentrations, from 200 ppb to 5 ppm. Uptake was observed to be highly dependent on initial aerosol pH. Significant uptake of αPO to aerosol was observed with initial pH < 0. When exposed to 200 ppb αPO, aerosol with pH = −1 doubled in volume, and 6% volume growth was observed at pH = 0. Aerosol with pH = 1 showed no growth. The extreme acidity required for efficient αPO uptake suggests that this chemistry is typically not a major route to formation of aerosol mass or organosulfates in the atmosphere. Partition coefficients (Kp) ranged from 0.2–1.6 × 10−4 m3 μg−1 and were correlated to initial particle acidity and particle organic content; particles with higher organic content had lower partition coefficients. Effective uptake coefficients (γ) ranged from 0.4 to 4.7 × 10−5 and are much lower than recently reported for uptake to bulk solutions. In experiments in which αPO was added to bulk H2SO4 solutions, phase separation was observed for mass loadings similar to those observed with particles, and product distributions were dependent on acid concentration. Liquid-liquid phase separation in bulk experiments, along with our observations of decreased uptake to particles with the largest growth factors, suggest an organic coating forms upon uptake to particles, limiting reactive uptake.
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Freedman, Miriam Arak. "Phase separation in organic aerosol." Chemical Society Reviews 46, no. 24 (2017): 7694–705. http://dx.doi.org/10.1039/c6cs00783j.
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Hiranuma, N., M. Kohn, M. S. Pekour, D. A. Nelson, J. E. Shilling, and D. J. Cziczo. "Droplet activation, separation, and compositional analysis: laboratory studies and atmospheric measurements." Atmospheric Measurement Techniques Discussions 4, no. 1 (January 24, 2011): 691–713. http://dx.doi.org/10.5194/amtd-4-691-2011.
Анотація:
Abstract. Droplets produced in a cloud condensation nucleus chamber as a function of supersaturation have been separated from unactivated aerosol particles using counterflow virtual impaction. Residual material after droplets were evaporated was chemically analyzed with an Aerodyne Aerosol Mass Spectrometer and the Particle Analysis by Laser Mass Spectrometry instrument. Experiments were initially conducted to verify activation conditions for monodisperse ammonium sulfate particles and to determine the resulting droplet size distribution as a function of supersaturation. Based on the observed droplet size, the counterflow virtual impactor cut-size was set to differentiate droplets from unactivated interstitial particles. Validation experiments were then performed to verify that only droplets with sufficient size passed through the counterflow virtual impactor for subsequent analysis. A two-component external mixture of monodisperse particles was also exposed to a supersaturation which would activate one of the types (ammonium sulfate) but not the other (polystyrene latex spheres). The mass spectrum observed after separation indicated only the former, validating separation of droplets from unactivated particles. Results from atmospheric measurements using this technique indicate that aerosol particles often activate predominantly as a function of particle size. Chemical composition is not irrelevant, however, and we observed enhancement of sulfate in droplet residuals using single particle analysis.
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Song, Young-Chul, Ariana G. Bé, Scot T. Martin, Franz M. Geiger, Allan K. Bertram, Regan J. Thomson та Mijung Song. "Liquid–liquid phase separation and morphologies in organic particles consisting of <i>α</i>-pinene and <i>β</i>-caryophyllene ozonolysis products and mixtures with commercially available organic compounds". Atmospheric Chemistry and Physics 20, № 19 (2 жовтня 2020): 11263–73. http://dx.doi.org/10.5194/acp-20-11263-2020.
Анотація:
Abstract. Liquid–liquid phase separation (LLPS) in organic aerosol particles can impact several properties of atmospheric particulate matter, such as cloud condensation nuclei (CCN) properties, optical properties, and gas-to-particle partitioning. Yet, our understanding of LLPS in organic aerosols is far from complete. Here, we report on the LLPS of one-component and two-component organic particles consisting of α-pinene- and β-caryophyllene-derived ozonolysis products and commercially available organic compounds of relevance to atmospheric organic particles. In the experiments involving single-component organic particles, LLPS was observed in 8 out of 11 particle types studied. LLPS almost always occurred when the oxygen-to-carbon elemental ratio (O:C) was ≤0.44 but did not occur when O:C was >0.44. The phase separation occurred by spinodal decomposition as well as the nucleation and growth mechanism, and when LLPS occurred, two liquid phases coexisted up to ∼100 % relative humidity (RH). In the experiments involving two-component organic particles, LLPS was observed in 23 out of 25 particles types studied. LLPS almost always occurred when the average was O:C ≤0.67 but never occurred when the average O:C was >0.67. The phase separation occurred by spinodal decomposition as well as the nucleation and growth mechanism. When LLPS occurred, two liquid phases coexisted up to ∼100 % RH. These results provide further evidence that LLPS is likely a frequent occurrence in organic aerosol particles in the troposphere, even in the absence of inorganic salts.
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Drozd, G. T., J. L. Woo та V. F. McNeill. "Self-limited uptake of α-pinene oxide to acidic aerosol: the effects of liquid–liquid phase separation and implications for the formation of secondary organic aerosol and organosulfates from epoxides". Atmospheric Chemistry and Physics 13, № 16 (22 серпня 2013): 8255–63. http://dx.doi.org/10.5194/acp-13-8255-2013.
Анотація:
Abstract. The reactive uptake of α-pinene oxide (αPO) to acidic sulfate aerosol was studied under humid conditions in order to gain insight into the effects of liquid–liquid phase separation on aerosol heterogeneous chemistry and to elucidate further the formation of secondary organic aerosol and organosulfates from epoxides. A continuous flow environmental chamber was used to monitor changes in diameter of monodisperse, deliquesced, acidic sulfate particles exposed to αPO at 25% and 50% RH (relative humidity). In order to induce phase separation and probe potential limits to particle growth from acidic uptake, αPO was introduced over a wide range of concentrations, from 200 ppb to 5 ppm. Uptake was observed to be highly dependent on initial aerosol pH. Significant uptake of αPO to aerosol was observed with initial pH < 0. When exposed to 200 ppb αPO, aerosol with pH = -0.5 showed 23% growth, and 6% volume growth was observed at pH = 0. Aerosol with pH = 1 showed no growth. The extreme acidity required for efficient αPO uptake suggests that this chemistry is typically not a major route to formation of aerosol mass or organosulfates in the atmosphere. Effective partition coefficients (Kp, eff) were in the range of (0.1–2) x 10-4 m3μg-1 and were correlated to initial particle acidity and particle organic content; particles with higher organic content had lower partition coefficients. Effective uptake coefficients (γeff) ranged from 0.1 to 1.1 x 10-4 and are much lower than recently reported for uptake to bulk solutions. In experiments in which αPO was added to bulk H2SO4 solutions, phase separation was observed for mass loadings similar to those observed with particles, and product distributions were dependent on acid concentration. Liquid–liquid phase separation in bulk experiments, along with our observations of decreased uptake to particles with the largest growth factors, suggests an organic coating forms upon uptake to particles, limiting reactive uptake.
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Zawadowicz, M. A., S. R. Proud, S. S. Seppalainen, and D. J. Cziczo. "Hygroscopic and phase separation properties of ammonium sulfate/organic/water ternary solutions." Atmospheric Chemistry and Physics Discussions 15, no. 5 (March 5, 2015): 6537–66. http://dx.doi.org/10.5194/acpd-15-6537-2015.
Анотація:
Abstract. Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Deliquescence and efflorescence of simple inorganic salt particles have been investigated by a variety of methods, such as IR spectroscopy, tandem mobility analysis and electrodynamic balance. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Many recent studies have focused on microscopy techniques that require deposition of the aerosol on a glass slide, possibly changing its surface properties. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance, and therefore, particles prepared in this study should mimic atmospheric mixed phase aerosol particles. The results of this study tend to be in agreement with previous microscopy experiments, with several key differences, which possibly reveal a size-dependent effect on phase separation in organic/inorganic aerosol particles.
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Miao, Wang, and Sergiy Ryzhkov. "RESEARCH OF SEPARATION GRADIENT AEROSOL TECHNOLOGIES FOR INTENSIFICATION OF HEAT AND MASS TRANSFER PROCESSES IN SYSTEMS OF HIGHLY TURBULENT DISPERSED BIPHASIC FLOWS. EMPLOYING THE SEPARATION GRADIENT AEROSOL TECHNOLOGIES FOR DESIGNING THE OIL SEPARATORS OF VENTING SYSTEMS IN GAS TURBINE ENGINES (G=200 m3/h)." Science Journal Innovation Technologies Transfer, no. 2019-3 (July 7, 2019): 75–84. http://dx.doi.org/10.36381/iamsti.3.2019.75-84.
Анотація:
The aim of present study was to design an oil separator for the venting systems of gas turbine engines at consumption of gaseous medium 200 m3/h. In order to accomplish the objective, we applied separation gradient aerosol technologies, which consider all the forces and effects that influence deposition of the highly dispersed particles. A scientific base is substantiated for the intensification of gradient processes of the transfer of aerosol media in the boundary layers of multifunctional surfaces in the purification of dispersed polyphase flows for developing the technical devices that ensure an increase in energy saving and ecological improvement of power plants. We designed a section-by-section structural scheme and a three-dimensional model of the oil separator in finite elements for the calculation of hydrodynamics and separation. The calculations were conducted of the hydrodynamic situation and particle trajectory in the flow area of an oil separator. Using the calculated distribution of speed in the oil separator at G=100…200 m3/h, it was determined that velocity in the coagulation profile does not exceed 10 m/s. It was established according to the results of static pressure distribution for G=100, 200 m3/h that the pressure differential in the separation coagulators reaches 2.5…3.9 kPa, respectively. Results of the calculation at G=100…200 m3/h demonstrated that the summary pulsation effect from the deposition of highly dispersed particles amounts to 25.1 %. Based on the calculations, we designed the prototype of an oil separator and tested it experimentally on the test bench in the form of an open type wind tunnel. Coefficient of the total effectiveness of purification was determined, which reaches 99.9 %. The modernization of purifiers for capturing the aerosols in different systems of power plants is possible based on the separation gradient aerosol technologies. The studies conducted make it possible to develop in the future a range of separators for gas consumption from 20 to 2000 m3/h.
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Córdoba-Jabonero, Carmen, Michaël Sicard, Albert Ansmann, Ana del Águila, and Holger Baars. "Separation of the optical and mass features of particle components in different aerosol mixtures by using POLIPHON retrievals in synergy with continuous polarized Micro-Pulse Lidar (P-MPL) measurements." Atmospheric Measurement Techniques 11, no. 8 (August 15, 2018): 4775–95. http://dx.doi.org/10.5194/amt-11-4775-2018.
Анотація:
Abstract. The application of the POLIPHON (POlarization-LIdar PHOtometer Networking) method is presented for the first time in synergy with continuous 24/7 polarized Micro-Pulse Lidar (P-MPL) measurements to derive the vertical separation of two or three particle components in different aerosol mixtures, and the retrieval of their particular optical properties. The procedure of extinction-to-mass conversion, together with an analysis of the mass extinction efficiency (MEE) parameter, is described, and the relative mass contribution of each aerosol component is also derived in a further step. The general POLIPHON algorithm is based on the specific particle linear depolarization ratio given for different types of aerosols and can be run in either 1-step (POL-1) or 2 steps (POL-2) versions with dependence on either the 2- or 3-component separation. In order to illustrate this procedure, aerosol mixing cases observed over Barcelona (NE Spain) are selected: a dust event on 5 July 2016, smoke plumes detected on 23 May 2016 and a pollination episode observed on 23 March 2016. In particular, the 3-component separation is just applied for the dust case: a combined POL-1 with POL-2 procedure (POL-1/2) is used, and additionally the fine-dust contribution to the total fine mode (fine dust plus non-dust aerosols) is estimated. The high dust impact before 12:00 UTC yields a mean mass loading of 0.6±0.1 g m−2 due to the prevalence of Saharan coarse-dust particles. After that time, the mean mass loading is reduced by two-thirds, showing a rather weak dust incidence. In the smoke case, the arrival of fine biomass-burning particles is detected at altitudes as high as 7 km. The smoke particles, probably mixed with less depolarizing non-smoke aerosols, are observed in air masses, having their origin from either North American fires or the Arctic area, as reported by HYSPLIT back-trajectory analysis. The particle linear depolarization ratio for smoke shows values in the 0.10–0.15 range and even higher at given times, and the daily mean smoke mass loading is 0.017±0.008 g m−2, around 3 % of that found for the dust event. Pollen particles are detected up to 1.5 km in height from 10:00 UTC during an intense pollination event with a particle linear depolarization ratio ranging between 0.10 and 0.15. The maximal mass loading of Platanus pollen particles is 0.011±0.003 g m−2, representing around 2 % of the dust loading during the higher dust incidence. Regarding the MEE derived for each aerosol component, their values are in agreement with others referenced in the literature for the specific aerosol types examined in this work: 0.5±0.1 and 1.7±0.2 m2 g−1 are found for coarse and fine dust particles, 4.5±1.4 m2 g−1 is derived for smoke and 2.4±0.5 m2 g−1 for non-smoke aerosols with Arctic origin, and a MEE of 2.4±0.8 m2 g−1 is obtained for pollen particles, though it can reach higher or lower values depending on predominantly smaller or larger pollen grain sizes. Results reveal the high potential of the P-MPL system, a simple polarization-sensitive elastic backscatter lidar working in a 24/7 operation mode, to retrieve the relative optical and mass contributions of each aerosol component throughout the day, reflecting the daily variability of their properties. In fact, this procedure can be simply implemented in other P-MPLs that also operate within the worldwide Micro-Pulse Lidar Network (MPLNET), thus extending the aerosol discrimination at a global scale. Moreover, the method has the advantage of also being relatively easily applicable to space-borne lidars with an equivalent configuration such as the ongoing Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) on board NASA CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) and the forthcoming Atmospheric Lidar (ATLID) on board the ESA EarthCARE mission.
Дисертації з теми "Aerosol particles separation":
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Gorkowski, Kyle J. "The Morphology and Equilibration of Levitated Secondary Organic Particles Under Controlled Conditions." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1067.
Анотація:
I advanced the understanding of particle morphology and its implications for the behavior and effects of atmospheric aerosol particles. I have developed new experimental methods for the Aerosol Optical Tweezers (AOT) system and expanded the AOT’s application into studying realistic secondary organic aerosol (SOA) particle phases. The AOT is a highly accurate system developed to study individual particles in real-time for prolonged periods of time. While previous AOT studies have focused on binary or ternary chemical systems, I have investigated complex SOA, and how they interact with other chemical phases, and the surrounding gas-phase. This work has led to new insights into liquid-liquid phase separation and the resulting particle morphology, the surface tension, solubility, and volatility of SOA, and diffusion coefficients of SOA phases. I designed a new aerosol optical tweezers chamber for delivering a uniformly mixed aerosol flow to the trapped droplet’s position. I used this chamber to determine the phase-separation morphology and resulting properties of complex mixed droplets. A series of experiments using simple compounds are presented to establish my ability to use the cavity enhanced Raman spectra to distinguish between homogenous single-phase, and phase-separated core-shell or partially-engulfed morphologies. I have developed a new algorithm for the analysis of whispering gallery modes (WGMs) present in the cavity enhanced Raman spectra retrieved from droplets trapped in the AOT. My algorithm improves the computational scaling when analyzing core-shell droplets (i.e. phase-separated or biphasic droplets) in the AOT, making it computationally practical to analyze spectra collected over many hours at a few Hz. I then demonstrate for the first time the capture and analysis of SOA on a droplet suspended in an AOT. I examined three initial chemical systems of aqueous NaCl, aqueous glycerol, and squalane at ~ 75% relative humidity. For each system I added α-pinene SOA – generated directly in the AOT chamber – to the trapped droplet. The resulting morphology was always observed to be a core of the initial droplet surrounded by a shell of the added SOA. By combining my AOT observations of particle morphology with results from SOA smog chamber experiments, I conclude that the α-pinene SOA shell creates no major diffusion limitations for water, glycerol, and squalane under humid conditions. My AOT experiments highlight the prominence of phase-separated core-shell morphologies for secondary organic aerosols interacting with a range of other chemical phases. The unique analytical capabilities of the aerosol optical tweezers provide a new approach for advancing the understanding of the chemical and physical evolution of complex atmospheric particulate matter, and the important environmental impacts of aerosols on atmospheric chemistry, air quality, human health, and climate change.
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Kirsch, Hans. "Entwicklung eines Verfahrens zur material- und struktursensitiven Trennung gasgetragener Partikel - Material and structure dependent separation of aerosol particles." Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-05292001-122009/.
Анотація:
The interest in nano particles from the view of basic and applied research has constantly risen in recent years. Since their physical properties are different from those of bulk materials, new industrial applications are emerging, e.g. in microelectronics. For quality control, particle production technologies call for on-line techniques that respond to the chemical nature of the particles. A particle generation process usually leads to particles with different surface properties. These surface properties, i.e. impurities ( like an oxygen layer ) or the crystal habit of single particles, determines much of their behaviour, especially in the diameter range of a few nanometers. While this fact has hardly been recognized, we anticipate that new technologies will establish a demand not only for analysis but also for separation of chemically pure particles with respect to their surface properties. In these PHD thesis we introduce a method and a device to separate aerosol particles according to their photoelectric properties. These strongly depend on particle surface composition as well as the particle morphology.
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Morcinek, Tomáš. "Separace aerosolových částic na polymerních membránách." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449708.
Анотація:
This diploma thesis deals with the separation of aerosol particles on membranes from polypropylene hollow fibers. As a source of particles, a desktop 3D printer using polymer filaments was used. Filtration efficiency and a pressure drop on a hollow polypropylene fiber membrane and a high efficiency particulate filter (HEPA filter) were monitored during filtration of particles from 3D print using filaments of acrylonitrile butadiene styrene, acrylonitrile styrene acrylate, polylactic acid and polyethylene terephthalate glycol at nearly the same air flow. The results achieved by both filer media are then compared and discussed. The results show that the hollow fiber membrane achieves better filtration efficiency at higher particle concentrations, while using the less emitting materials, the efficiency of the HEPA filter was higher or the same. The total filtration efficiency calculated from all experiments with all filaments was higher for the hollow fiber membrane with higher pressure drop at the same time.
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Nahin, Md Minal. "Modeling and experimenting a novel inverted drift tube device for improved mobility analysis of aerosol particles." Thesis, 2017. https://doi.org/10.7912/C2HW83.
Анотація:
Indiana University-Purdue University Indianapolis (IUPUI)Ion Mobility Spectrometry (IMS) is an analytical technique for separation of charged particles in the gas phase. The history of IMS is not very old, and in this century, the IMS technique has grown rapidly in the advent of modern instruments. Among currently available ion mobility spectrometers, the DTIMS, FAIMS, TWIMS, DMA are notable. Though all the IMS systems have some uniqueness in case of particle separation and detection, however, all instruments have common shortcomings. They lack in resolution, which is independent of mobility of different charged particles and they are not able to separate bigger particles (20 120 nm) with good accuracy. The work presented here demonstrates a new concept of IMS technique at atmospheric pressure which has a resolution much higher than that of the currently available DTIMS (Drift Tube Ion Mobility Spectrometry) instruments. The unique feature of this instrument is the diffusion auto-correction. Being tunable, It can separate the wide range of particles of different diameters. The working principle of this new IMS technique is different from the typical DTIMS and to simply put, it can be considered as an inversion of commonly used technique, so termed as Inverted Drift Tube (IDT).The whole work performed here can be divided into three major phases. In the first phase, the analytical solution was derived for two new separation techniques: IPF (Intermittent push flow) and NSP (Nearly stopping potential) separations. In the next phase, simulations were done to show the accuracy of the analytical solution. An ion optics simulator software called SIMION 8.1 was used for conducting the simulation works. These simulations adopted the statistical diffusion (SDS) collision algorithm to emulate the real scenario in gas phase more precisely. In the last phase, a prototype of experimental setup was built. The experimental results were then validated by simulated results.
Частини книг з теми "Aerosol particles separation":
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Bianchi, Thomas S. "Dissolved Gases in Water." In Biogeochemistry of Estuaries. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195160826.003.0012.
Анотація:
Dissolved gases are critically important in many of the biogeochemical cycles of estuaries and coastal waters. However, only recently have there been large-scale collaborative efforts addressing the importance of coupling between estuaries and the atmosphere. For example, the Biogas Transfer in Estuaries (BIOGEST) project, which began in 1996, was focused on determining the distribution of biogases [CO2, CH4, CO, non-methane hydrocarbons, N2O, dimethyl sulfide (DMS), carbonyl sulfide (COS), volatile halogenated organic compounds, and some biogenic volatile metals] in European estuaries and their impact on global budgets (Frankignoulle and Middelburg, 2002). The role of the estuaries and other coastal ocean environments as global sources and/or sinks of key greenhouse gases, like CO2, have also been a subject of intense interest in recent years (Frankignoulle et al., 1996; Cai and Wang, 1998; Raymond et al., 1997, 2000; Cai, 2003; Wang and Cai, 2004). Similarly, O2 transfer across the air–water interface is critical for the survival of most aquatic organisms. Unfortunately, many estuaries around the world are currently undergoing eutrophication, which commonly results in low O2 concentrations (or hypoxic ≤ 2 mg L−1), due to excessive nutrient loading in these systems (Rabalais and Turner, 2001; Rabalais and Nixon, 2002). To understand how gases are transferred across the air–water boundary we will first examine the dominant atmospheric gases and physical parameters that control their transport and solubility in natural waters. The atmosphere is also composed of aerosols, which are defined as condensed phases of solid or liquid particles, suspended in state, that have stability to gravitational separation over a period of observation (Charlson, 2000). Chemical composition and speciation in atmospheric aerosols is important to understanding their behavior after deposition, and is strongly linked with the dominant sources of aerosols (e.g., windblown dust, seasalt, combustion). The importance of aerosol deposition to estuaries and coastal waters, via precipitation (rain and snow) and/or dry particle deposition, has received considerable attention in recent years. For example, dry and wet deposition of nutrients (Paerl et al., 2002; Pollman et al., 2002) and metal contaminants (Siefert et al., 1998; Guentzel et al., 2001) has proven to be significant in biogeochemical budgets in wetlands and estuaries.
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Kashima, Keita, Tomoki Takahashi, Ryo-ichi Nakayama, and Masanao Imai. "Innovative Separation Technology Utilizing Marine Bioresources: Multifaceted Development of a Chitosan-Based System Leading to Environmentally-Friendly Processes." In Chitin and Chitosan - Physicochemical Properties and Industrial Applications [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95839.
Анотація:
Chitosan, known as a most typical marine biological polymer, has a fruitful capability of biocompatible gel formation. Attempts of chitosan have been made to develop it from the multifaceted viewpoint of separation technology. The physicochemical properties of chitosan containing a lot of hydroxyl groups and reactive amino groups help to build the characteristic polymer networks. The deacetylation degree of chitosan is found as the most influential factor to regulate properties of chitosan hydrogels. The antibacterial activity of the chitosan membrane is one of its notable abilities because of its practical application. The chitosan, its derivatives, and the complex formation with other substances has been used for applications in filtration and membrane separation processes. Adsorption processes based on chitosan have been also developed widely. Moreover, complex of chitosan gel helps to immobilize adsorbent particles. The chitosan membrane immobilizing Prussian-Blue for cesium ion removal from the aqueous phase is one of the leading cases. To elaborate the adsorption behavior on the chitosan immobilizing adsorbent, the isothermal equilibrium and mass transfer characteristics can be discussed. The adsorption process using chitosan-based membranes in combination with filtration in a flow process is advantageous compared with the batch process. More advanced studies of chitosan aerogel and chitosan nanofibers have been proceeded recently, especially for adapting to water purification and air filtration.
Тези доповідей конференцій з теми "Aerosol particles separation":
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Jaworek, A., A. Marchewicz, T. Czech, A. Krupa, A. Sobczyk, and K. Adamiak. "Magnetic separation of submicron particles from aerosol phase." In The Fifth National Congress of Environmental Engineering. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2016. http://dx.doi.org/10.1201/9781315281971-20.
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Gorny, Ramona Klaudia, Gerhard Schaldach, Peter Walzel, and Markus Thommes. "Spray Conditioning for the Preparation of Spray Dried Submicron Particles." In ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia: Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4701.
Анотація:
Particle size reduction down to the submicron range (0.1-1 µm) is an effective option to increase the bioavailabilityof low water soluble active pharmaceutical ingredients. According to the Nernst-Brunner equation, the preparation of submicron sized particles increases the specific surface area, thus increases the dissolution rate. Conventional spray drying devices for submicron particles show certain limitations. The main challenge is the preparation of small and uniform droplets during the atomisation step. In this work, fine droplets were generated combining a nozzle with a droplet separator. Therefore, the aerosol is generated with a pneumatic nozzle and is sprayed into a cyclone droplet separator. Depending on the characteristics of the cyclone, droplets larger than the cut-off-size were separated and returned into the liquid feed. The conditioned aerosol at the top of the cyclone separator can then be introduced into the drying chamber. With this concept the usable part is separated, thus no classification process after drying is necessary. The investigations show that the dependencies during atomisation of the droplets size on the liquid-to-gas mass flow ratio µm and the liquid properties (e.g. viscosity) do not apply to the separation step. The conditioned aerosol only depends on the separation characteristics of the cyclone droplet separator. However, the amount of droplets separated is determined by the atomisation step. Hence, the amount of droplets smaller than the cut-off-size can be increased by decreasing the droplet size of the primary aerosol. This is realised by secondary droplet fragmentation. An impact surface causes breakup of the droplets of theprimary aerosol before separation. The investigations show an increased amount of droplets <2µm.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4701
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Yin, Xiaobo, Koki Yamamoto, Ernest Apondi Wandera, Yoshio Ichinose, Seiji Kanba, Takashi Kondo, and Makoto Hasegawa. "Separation, Sensing, and Metagenomic Analysis of Aerosol Particles Using MMD Sensors." In 2018 IEEE Sensors. IEEE, 2018. http://dx.doi.org/10.1109/icsens.2018.8589778.
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Lall, A. A., A. Terray, and S. J. Hart. "On-the-fly cross flow laser guided separation of aerosol particles." In SPIE NanoScience + Engineering, edited by Kishan Dholakia and Gabriel C. Spalding. SPIE, 2010. http://dx.doi.org/10.1117/12.860742.
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Kim, Jinho, and Jim S. Chen. "Effect of Inhaling Patterns on Aerosol Drug Delivery: CFD Simulation." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66685.
Анотація:
Inhaled Pharmaceutical Aerosols (IPAs) delivery has great potential in treatment of a variety of respiratory diseases, including asthma, pulmonary diseases, and allergies. Aerosol delivery has many advantages. It delivers medication directly to where it is needed and it is effective in much lower doses than required for oral administration. Currently, there are several types of IPA delivery systems, including pressurized metered dose inhaler (pMDI), the dry powder inhaler (DPI), and the medical nebulizer. IPAs should be delivered deep into the respiratory system where the drug substance can be absorbed into blood through the capillaries via the alveoli. Researchers have proved that most aerosol particles with aerodynamic diameter of about 1–5 μm, if slowly and deeply inhaled, could be deposited in the peripheral regions that are rich in alveoli [1–3]. The purpose of this study is to investigate the effects of various inhaling rates with breath-holding pause on the aerosol deposition (Dp = 0.5–5 μm) in a human upper airway model extending from mouth to 3rd generation of trachea. The oral airway model is three dimensional and non-planar configurations. The dimensions of the model are adapted from a human cast. The air flow is assumed to be unsteady, laminar, and incompressible. The investigation is carried out by Computational Fluid Dynamics (CFD) using the software Fluent 6.2. The user-defined function (UDF) is employed to simulate the cyclic inspiratory flows for different IPA inhalation patterns. When an aerosol particle enters the mouth respiratory tract, its particles experience abrupt changes in direction. The secondary flow changes its direction as the airflow passes curvature. Intensity of the secondary flow is strong after first bend at pharynx and becomes weaker after larynx. In flow separation, a particle can be trapped and follow the eddy and deposit on the surface. Particle deposition fraction generally increases as particle size and inhaling airflow velocity increase.
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Fischer, Felix, Andreas Andris, Wolfgang Lippmann, and Antonio Hurtado. "Particle Deposition by Thermophoresis Under High Temperature Conditions in a Helium-Flow." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66391.
Анотація:
The continuous generation of graphite dust particles in the core of a High Temperature Reactor (HTR) is one of the key challenges of safety during the operation. The graphite dust particles emerge from relative movements between the fuel elements or from contact to the graphitic reflector structure and could be contaminated by diffused fission products from the fuel elements. They are distributed from the reactor core to the entire reactor coolant system. In case of a depressurisation accident, a release of the contaminated dust into the confinement is possible. In addition, the contaminated graphite dust can decrease the life cycle of the coolant system due to chemical interactions. On the one hand, the knowledge of the behaviour of graphite dust particles under HTR conditions using helium as the flow medium is a key factor to develop an effective filter system for the discussed issue. On the other hand, it also provides a possibility to access the activity distribution in the reactor. The behaviour can be subdivided into short-term effects like transport, deposition, remobilization and long-term effects like reactions with material surfaces. The Technische Universität Dresden has installed a new high-temperature test facility to study the short-term effects of deposition of graphite dust particles. The flow channel has a length of 5m and a tube diameter of 0.05m. With helium as the flow medium, the temperature can be up to 950 °C in the channel center and 120 °C on the sample surface, the Reynolds number can be varied from 150 up to 1000. The particles get dispersed into the accelerated and heated flow medium in the flow channel. Next, the aerosol is passing a 3 m long adiabatic section to ensure homogenous flow conditions. After passing the flow straightener, it enters the optically accessible measurement path made from quartz glass. In particular, this test facility offers the possibility to analyse the influence of the thermophoretic effect separately. For this, an optionally cooled sample can be placed in the measuring area. The thickness of the particle layer on the sample is estimated with a 3D Laser scanning microscope. The particle concentration above the sample is measured with an aerosol particle sizer (APS). Particle Image Velocimetry (PIV) detects the flow-velocity field and provides data to estimate the shear velocity. In combination with the measured temperature-field, all necessary information for the calculation of the particle deposition and particle relaxation time are available. The measurements are compared to results of theoretical works from the literature. The experimental database is relevant especially for CFD-developers, for model development, and model verification. A wide range of phenomena like particle separation, local agglomeration of particles with a specific particle mass and selective remobilization can be explained in this way. Thus, this work contributes to a realistic analysis of Nuclear Safety.
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Gu¨ntay, S., D. Suckow, A. Dehbi, and R. Kapulla. "ARTIST: Introduction and First Results." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49553.
Анотація:
ARTIST (Aerosol Trapping In a Steam Generator) is a seven-phase international project (2003–2007) which investigates aerosol and droplet retention in a model steam generator under dry, wet and accident management conditions, respectively. The test section is comprised of a scaled steam generator tube bundle consisting of 270 tubes and 3 stages, one 1:1 separator unit, and one 1:1 dryer unit. As a prelude to the ARTIST project, four tests are conducted in the ARTIST bundle within the 5th EU FWP SGTR. These first tests address aerosol deposition phenomena on two different scales: near the tube break, where the gas velocities are sonic, and far away from the break, where the flow velocities are three orders of magnitude lower. With a dry bundle and the full flow representing the break stage conditions, there is strong evidence that the TiO2 aerosols used (AMMD 2–4 μm, 32 nm primary particles) disintegrate into much smaller particles because of the sonic conditions at the break, hence promoting particle escape from the secondary and lowering the overall DF, which is found to be between 2.5 and 3. With a dry bundle and a small flow reproducing the far-field velocities, the overall bundle DF is of the order of 5, implying a DF of about 1.9 per stage. Extrapolating the results of the dry tests, it turns out that for steam generators with 9 or more stages, it is expected that substantial DF’s could be achieved when the break is located near the tube sheet region. In addition, better decontamination is expected using more representative proxies of severe accident aerosols (sticky, multicomponent particles), a topic which is yet to be investigated. When the bundle is flooded, the DF is between 45 and 5740, depending on the mass flow rate, the steam content, and the water submergence. The presence of steam in the carrier gas and subsequent condensation inside the broken tube causes aerosol deposition and blockages near the break, leading to an increase in the primary pressure. This has implications for real plant conditions, as aerosol deposits inside the broken tube will cause more flow to be diverted to the intact tubes, with a corresponding reduction in the source term to the secondary.
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Yeo, Leslie Y., and James R. Friend. "Surface Acoustic Waves: A New Paradigm for Driving Ultrafast Biomicrofluidics." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18517.
Анотація:
Surface acoustic waves (SAWs), which are 10 MHz order surface waves roughly 10 nm in amplitude propagating on the surface of a piezoelectric substrate, can offer a powerful method for driving fast microfluidic actuation and microparticle or biomolecule manipulation. We demonstrate that sessile drops can be linearly translated on planar substrates or fluid can be pumped through microchannels at typically one to two orders of magnitude faster than that achievable through current microfluidic technologies. Micromixing can be induced in the same microchannel in which fluid is pumped using the SAW simply by changing the SAW frequency to superimpose a chaotic oscillatory flow onto the uniform through flow. Strong inertial microcentrifugation for micromixing and particle concentration or separation can also be induced via symmetry-breaking. At low SAW amplitudes below that at which flow commences, the transverse standing wave that arises across the microchannel afford particle aggregation and hence sorting on nodal lines. Other microfluidic manipulations are also possible with the SAW. For example, capillary waves excited on a sessile drop by the SAW can be exploited for microparticle or nanoparticle collection and sorting. At higher amplitudes, the large substrate accelerations drives rapid destabilization of the drop interface giving rise to inertial liquid jets or atomization to produce 1–10 μm monodispersed aerosol droplets. These have significant implications for microfluidic chip mass spectrometry interfacing or pulmonary drug delivery. The atomization also provides a convenient means for the synthesis of 150–200 nm polymer or protein particles or to encapsulate proteins, peptides and other therapeutic molecules within biodegradable polymeric shells for controlled release drug delivery. The atomization of thin films containing polymer solutions, in addition, gives produces a unique regular, long-range spatial polymer spot patterning effect whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for surface patterning without requiring physical or chemical templating.
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Zhong, Wen, and Ning Pan. "Filtration Model of Aerosol Particles by Fibrous Filters." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60873.
Анотація:
Aerosol filtration by fibrous filters is one of the most common methods of separating and removing particles in micro and sub-micro size ranges. The statistical genesis of this process can be regarded as the interactions and the resulting equilibrium among particle and fiber cells that comprise the system. Therefore a statistical mechanics approach, the Ising’s model, combined with Monte Carlo simulation, is employed in studying the process of the aerosol filtration through fibrous filters. The process is modeled as consisting of numerous cell state exchanges driven by the difference of system energy after and before a particle moves from one cell to the other and/or deposits on a fiber cell. With the use of a simpler binary algorithm, this approach is capable of realistically simulating the complicated mechanisms involved in the filtration process. For verification, simulations are carried out for the behaviors of aerosol particles of different sizes through isotropic fiber filters with various volume fractions. Simulation results are in good agreements with reported experimental data.
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Badhan, Antara, Luz Bugarin, and Shaolin Mao. "Numerical Prediction of Collection Efficiency of a Personal Sampler Based on Cyclone Principle." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21229.
Анотація:
A personal bio-aerosol sampler is a self-contained, operation flexible, high-efficient device for indoor air quality (IAQ) and health risk exposure monitoring and measurement. Bio-aerosols such germ-laden viruses, microbial species, airborne microorganisms and volatile organic compounds (VOC) are sucked into the sampler and are deposited on the inner wall surface based on cyclone principal. The major concern with bio-aerosol samplers is the collection efficiency. In this study, we use computational fluid dynamics (CFD) tools to evaluate key design parameters, specifically the inlet tube angle and collection tube inner wall roughness. 3D incompressible turbulent flow is simulated using commercial software ANSYS FLUENT. Reynolds stress model (RSM) is used to investigate the turbulence effect with the following boundary conditions (velocity-inlet boundary condition at inlet, outflow boundary condition at outlet and no slip at walls). The numerical approach for air-aerosol interaction is based on an Eulerian-Lagrangian fluid dynamics framework, where the particles or droplets trajectories are computed in a Lagrangian method (discrete phase element) and then conjugate these particles to the continuous phase in the Eulerian frame. The variation of inlet angle affects the collection efficiency of the cyclone separator. In addition, the flow characterizations with different velocity fluctuation profiles validate the continuous phase model. The development and evolution of the vortex core region for the axial velocity are obtained and evaluated in the simulation of the cyclonic flow.