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Статті в журналах з теми "Aerosol origins":
1
EVERTS, SARAH. "AEROSOL ORIGINS." Chemical & Engineering News 85, no. 10 (March 5, 2007): 10. http://dx.doi.org/10.1021/cen-v085n010.p010a.
2
Song, Congbo, Manuel Dall'Osto, Angelo Lupi, Mauro Mazzola, Rita Traversi, Silvia Becagli, Stefania Gilardoni, et al. "Differentiation of coarse-mode anthropogenic, marine and dust particles in the High Arctic islands of Svalbard." Atmospheric Chemistry and Physics 21, no. 14 (July 28, 2021): 11317–35. http://dx.doi.org/10.5194/acp-21-11317-2021.
Анотація:
Abstract. Understanding aerosol–cloud–climate interactions in the Arctic is key to predicting the climate in this rapidly changing region. Whilst many studies have focused on submicrometer aerosol (diameter less than 1 µm), relatively little is known about the supermicrometer aerosol (diameter above 1 µm). Here, we present a cluster analysis of multiyear (2015–2019) aerodynamic volume size distributions, with diameter ranging from 0.5 to 20 µm, measured continuously at the Gruvebadet Observatory in the Svalbard archipelago. Together with aerosol chemical composition data from several online and offline measurements, we apportioned the occurrence of the coarse-mode aerosols during the study period (mainly from March to October) to anthropogenic (two sources, 27 %) and natural (three sources, 73 %) origins. Specifically, two clusters are related to Arctic haze with high levels of black carbon, sulfate and accumulation mode (0.1–1 µm) aerosol. The first cluster (9 %) is attributed to ammonium sulfate-rich Arctic haze particles, whereas the second one (18 %) is attributed to larger-mode aerosol mixed with sea salt. The three natural aerosol clusters were open-ocean sea spray aerosol (34 %), mineral dust (7 %) and an unidentified source of sea spray-related aerosol (32 %). The results suggest that sea-spray-related aerosol in polar regions may be more complex than previously thought due to short- and long-distance origins and mixtures with Arctic haze, biogenic and likely blowing snow aerosols. Studying supermicrometer natural aerosol in the Arctic is imperative for understanding the impacts of changing natural processes on Arctic aerosol.
3
Xia, Junji, Fengrong Zhu, Xingbing Zhao, Jing Liu, Hu Liu, Guotao Yuan, Qinning Sun, et al. "Optical Properties and Possible Origins of Atmospheric Aerosols over LHAASO in the Eastern Margin of the Tibetan Plateau." Remote Sensing 16, no. 10 (May 10, 2024): 1695. http://dx.doi.org/10.3390/rs16101695.
Анотація:
The accuracy of cosmic ray observations by the Large High Altitude Air Shower Observatory Wide Field-of-View Cherenkov/Fluorescence Telescope Array (LHAASO-WFCTA) is influenced by variations in aerosols in the atmosphere. The solar photometer (CE318-T) is extensively utilized within the Aerosol Robotic Network as a highly precise and reliable instrument for aerosol measurements. With this CE318-T 23, 254 sets of valid data samples over 394 days from October 2020 to October 2022 at the LHAASO site were obtained. Data analysis revealed that the baseline Aerosol Optical Depth (AOD) and Ångström Exponent (AE) at 440–870 nm (AE440–870nm) of the aerosols were calculated to be 0.03 and 1.07, respectively, suggesting that the LHAASO site is among the most pristine regions on Earth. The seasonality of the mean AOD is in the order of spring > summer > autumn = winter. The monthly average maximum of AOD440nm occurred in April (0.11 ± 0.05) and the minimum was in December (0.03 ± 0.01). The monthly average of AE440–870nm exhibited slight variations. The seasonal characterization of aerosol types indicated that background aerosol predominated in autumn and winter, which is the optimal period for the absolute calibration of the WFCTA. Additionally, the diurnal daytime variations of AOD and AE across the four seasons are presented. Our analysis also indicates that the potential origins of aerosol over the LHAASO in four seasons were different and the atmospheric aerosols with higher AOD probably originate mainly from Northern Myanmar and Northeast India regions. These results are presented for the first time, providing a detailed analysis of aerosol seasonality and origins, which have not been thoroughly documented before in this region, also enriching the valuable materials on aerosol observation in the Hengduan Mountains and Tibetan Plateau.
4
Laskin, Alexander, Julia Laskin, and Sergey A. Nizkorodov. "Mass spectrometric approaches for chemical characterisation of atmospheric aerosols: critical review of the most recent advances." Environmental Chemistry 9, no. 3 (2012): 163. http://dx.doi.org/10.1071/en12052.
Анотація:
Environmental contextAtmospheric aerosols have profound effects on the environment through several physicochemical processes, such as absorption and scattering of sunlight, heterogeneous gas–particle reactions and adverse effects on the respiratory and cardiovascular systems. Understanding aerosol atmospheric chemistry and its environmental impact requires comprehensive characterisation of the physical and chemical properties of particles. Results from mass spectrometry provide important new insights into the origin of atmospheric aerosols, the evolution of their physicochemical properties, their reactivity and their effect on the environment. AbstractThis manuscript presents an overview of the most recent instrument developments for the field and laboratory applications of mass spectrometry (MS) to investigate the chemistry and physics of atmospheric aerosols. A range of MS instruments, employing different sample introduction methods, ionisation and mass detection techniques are used both for ‘online’ and ‘offline’ characterisation of aerosols. Online MS techniques enable detection of individual particles with simultaneous measurement of particle size distributions and aerodynamic characteristics and are ideally suited for field studies that require high temporal resolution. Offline MS techniques provide a means for detailed molecular-level analysis of aerosol samples, which is essential to gain fundamental knowledge regarding aerosol chemistry, mechanisms of particle formation and atmospheric aging. Combined, complementary MS techniques provide comprehensive information on the chemical composition, size, morphology and phase of aerosols – data of key importance for evaluating hygroscopic and optical properties of particles, their health effects, understanding their origins and atmospheric evolution. Over the last few years, developments and applications of MS techniques in aerosol research have expanded remarkably as evident by skyrocketing publication statistics. The goal of this review is to present the most recent developments in the field of aerosol mass spectrometry for the time period of late 2010 to early 2012, which have not been conveyed in previous reviews.
5
Hofer, Sabine, Norbert Hofstätter, Albert Duschl, and Martin Himly. "SARS-CoV-2-Laden Respiratory Aerosol Deposition in the Lung Alveolar-Interstitial Region Is a Potential Risk Factor for Severe Disease: A Modeling Study." Journal of Personalized Medicine 11, no. 5 (May 19, 2021): 431. http://dx.doi.org/10.3390/jpm11050431.
Анотація:
COVID-19, predominantly a mild disease, is associated with more severe clinical manifestation upon pulmonary involvement. Virion-laden aerosols and droplets target different anatomical sites for deposition. Compared to droplets, aerosols more readily advance into the peripheral lung. We performed in silico modeling to confirm the secondary pulmonary lobules as the primary site of disease initiation. By taking different anatomical aerosol origins into consideration and reflecting aerosols from exhalation maneuvers breathing and vocalization, the physicochemical properties of generated respiratory aerosol particles were defined upon conversion to droplet nuclei by evaporation at ambient air. To provide detailed, spatially-resolved information on particle deposition in the thoracic region of the lung, a top-down refinement approach was employed. Our study presents evidence for hot spots of aerosol deposition in lung generations beyond the terminal bronchiole, with a maximum in the secondary pulmonary lobules and a high preference to the lower lobes of both lungs. In vivo, initial chest CT anomalies, the ground glass opacities, resulting from partial alveolar filling and interstitial thickening in the secondary pulmonary lobules, are likewise localized in these lung generations, with the highest frequency in both lower lobes and in the early stage of disease. Hence, our results suggest a disease initiation right there upon inhalation of virion-laden respiratory aerosols, linking the aerosol transmission route to pathogenesis associated with higher disease burden and identifying aerosol transmission as a new independent risk factor for developing a pulmonary phase with a severe outcome.
6
Worton, D. R., A. H. Goldstein, D. K. Farmer, K. S. Docherty, J. L. Jimenez, J. B. Gilman, W. C. Kuster, et al. "Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California." Atmospheric Chemistry and Physics Discussions 11, no. 6 (June 20, 2011): 17071–125. http://dx.doi.org/10.5194/acpd-11-17071-2011.
Анотація:
Abstract. In this paper we report chemically resolved measurements of organic aerosol (OA) and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at the Blodgett Forest Research Station, California. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA). The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In situ measurements of particle phase molecular markers were dominated by secondary compounds and could be categorized into three factors or sources: (1) aged biomass burning emissions and oxidized urban emissions, (2) oxidation products of temperature-driven local biogenic emissions and (3) local light-driven emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g., temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher due to more substantial emissions of isoprene and enhanced photochemistry. Methyl chavicol oxidation contributed similarly to OA during both identified meteorological periods. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during cooler conditions, even though emissions of the precursors were lower. Following the first precipitation event of the fall the abundances of the monoterpene oxidation products increased dramatically, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO), consistent with previous observations, while being comprised of mostly non-fossil carbon (>75 %). The correlation between OA and an anthropogenic tracer does not necessarily identify the source of the carbon as being anthropogenic but instead suggests a coupling between the anthropogenic and biogenic components in the air mass that might be related to the source of the oxidant and/or the aerosol sulfate. Observations of organosulfates of isoprene and α-pinene provided evidence for the likely importance of aerosol sulfate in spite of neutralized aerosol. This is in contrast to laboratory studies where strongly acidic seed aerosols were needed in order to form these compounds. These compounds together represented only a minor fraction (< 1 %) of the total OA mass and suggest that other mechanisms, e.g., NOx enhancement of oxidant levels, are more likely to be responsible for the majority of the anthropogenic enhancement of biogenic secondary organic aerosol observed at this site.
7
Worton, D. R., A. H. Goldstein, D. K. Farmer, K. S. Docherty, J. L. Jimenez, J. B. Gilman, W. C. Kuster, et al. "Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California." Atmospheric Chemistry and Physics 11, no. 19 (October 12, 2011): 10219–41. http://dx.doi.org/10.5194/acp-11-10219-2011.
Анотація:
Abstract. In this paper we report chemically resolved measurements of organic aerosol (OA) and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at the Blodgett Forest Research Station, California from 15 August–10 October 2007. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA). The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In situ measurements of particle phase molecular markers were dominated by secondary compounds and along with gas phase compounds could be categorized into six factors or sources: (1) aged biomass burning emissions and oxidized urban emissions, (2) oxidized urban emissions (3) oxidation products of monoterpene emissions, (4) monoterpene emissions, (5) anthropogenic emissions and (6) local methyl chavicol emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g. temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher during the first half of the campaign (15 August–12 September) due to more substantial emissions of isoprene and enhanced photochemistry. The oxidation of methyl chavicol, an oxygenated terpene emitted by ponderosa pine trees, contributed similarly to OA throughout the campaign. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during the cooler conditions in the latter half of the campaign (13 September–10 October), even though emissions of the precursors were lower, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO), consistent with previous observations, while being comprised of mostly non-fossil carbon (>75%). The correlation between OA and an anthropogenic tracer does not necessarily identify the source of the carbon as being anthropogenic but instead suggests a coupling between the anthropogenic and biogenic components in the air mass that might be related to the source of the oxidant and/or the aerosol sulfate. Observations of organosulfates of isoprene and α-pinene provided evidence for the likely importance of aerosol sulfate in spite of neutralized aerosol although acidic plumes might have played a role upwind of the site. This is in contrast to laboratory studies where strongly acidic seed aerosols were needed in order to form these compounds. These compounds together represented only a minor fraction (<1%) of the total OA mass, which may be the result of the neutralized aerosol at the site or because only a small number of organosulfates were quantified. The low contribution of organosulfates to total OA suggests that other mechanisms, e.g. NOx enhancement of oxidant levels, are likely responsible for the majority of the anthropogenic enhancement of biogenic secondary organic aerosol observed at this site.
8
Chrit, Mounir, Karine Sartelet, Jean Sciare, Jorge Pey, Nicolas Marchand, Florian Couvidat, Karine Sellegri, and Matthias Beekmann. "Modelling organic aerosol concentrations and properties during ChArMEx summer campaigns of 2012 and 2013 in the western Mediterranean region." Atmospheric Chemistry and Physics 17, no. 20 (October 23, 2017): 12509–31. http://dx.doi.org/10.5194/acp-17-12509-2017.
Анотація:
Abstract. In the framework of the Chemistry-Aerosol Mediterranean Experiment, a measurement site was set up at a remote site (Ersa) on Corsica Island in the northwestern Mediterranean Sea. Measurement campaigns performed during the summers of 2012 and 2013 showed high organic aerosol concentrations, mostly from biogenic origin. This work aims to represent the organic aerosol concentrations and properties (oxidation state and hydrophilicity) using the air-quality model Polyphemus with a surrogate approach for secondary organic aerosol (SOA) formation. Biogenic precursors are isoprene, monoterpenes and sesquiterpenes. In this work, the following model oxidation products of monoterpenes are added: (i) a carboxylic acid (MBTCA) to represent multi-generation oxidation products in the low-NOx regime, (ii) organic nitrate chemistry and (iii) extremely low-volatility organic compounds (ELVOCs) formed by ozonolysis. The model shows good agreement of measurements of organic concentrations for both 2012 and 2013 summer campaigns. The modelled oxidation property and hydrophilic organic carbon properties of the organic aerosols also agree reasonably well with the measurements. The influence of the different chemical processes added to the model on the oxidation level of organics is studied. Measured and simulated water-soluble organic carbon (WSOC) concentrations show that even at a remote site next to the sea, about 64 % of the organic carbon is soluble. The concentrations of WSOC vary with the origins of the air masses and the composition of organic aerosols. The marine organic emissions only contribute to a few percent of the organic mass in PM1, with maxima above the sea.
9
Hsieh, W. C., W. D. Collins, Y. Liu, J. C. H. Chiang, C. L. Shie, K. Caldeira, and L. Cao. "Climate response due to carbonaceous aerosols and aerosol-induced SST effects in NCAR community atmospheric model CAM3.5." Atmospheric Chemistry and Physics 13, no. 15 (August 5, 2013): 7489–510. http://dx.doi.org/10.5194/acp-13-7489-2013.
Анотація:
Abstract. This study used the Community Atmospheric Model 3.5 (CAM3.5) to investigate the effects of carbonaceous aerosols on climate. The simulations include control runs with 3 times the mass of carbonaceous aerosols as compared to the model's default carbonaceous aerosol mass, as well as no-carbon runs in which carbonaceous aerosols were removed. The slab ocean model (SOM) and the fixed sea surface temperature (SST) were used to examine effects of ocean boundary conditions. Throughout this study, climate response induced by aerosol forcing was mainly analyzed in the following three terms: (1) aerosol radiative effects under fixed SST, (2) effects of aerosol-induced SST feedbacks, and (3) total effects including effects of aerosol forcing and SST feedbacks. The change of SST induced by aerosols has large impacts on distribution of climate response; the magnitudes in response patterns such as temperature, precipitation, zonal winds, mean meridional circulation, radiative fluxes, and cloud coverage are different between the SOM and fixed SST runs. Moreover, different spatial responses between the SOM and fixed SST runs can also be seen in some local areas. This implies the importance of SST feedbacks on simulated climate response. The aerosol dimming effects cause a cooling predicted at low layers near the surface in most carbonaceous aerosol source regions. The temperature response shows a warming (cooling) predicted in the north (south) high latitudes, suggesting that aerosol forcing can cause climate change in regions far away from its origins. Our simulation results show that direct and semidirect radiative forcing due to carbonaceous aerosols decreases rainfall in the tropics. This implies that carbonaceous aerosols have possibly strong influence on weakening of the tropical circulation. Most changes in precipitation are negatively correlated with changes of radiative fluxes at the top of model. The changes in radiative fluxes at top of model are physically consistent with the response patterns in cloud fields. On global average, low-level cloud coverage increases, and mid- and high-level cloud coverage decreases in response to changes in radiative energy induced by aerosol forcing. An approximated moisture budget equation was analyzed in order to understand physical mechanism of precipitation changes induced by carbonaceous aerosols. Our results show that changes in tropical precipitation are mainly dominated are mainly dominated by the dynamic effect (i.e., vertical moisture transport carried by the perturbed flow).
10
Shcherbakov, Valery, Olivier Jourdan, Christiane Voigt, Jean-Francois Gayet, Aurélien Chauvigne, Alfons Schwarzenboeck, Andreas Minikin, et al. "Porous aerosol in degassing plumes of Mt. Etna and Mt. Stromboli." Atmospheric Chemistry and Physics 16, no. 18 (September 23, 2016): 11883–97. http://dx.doi.org/10.5194/acp-16-11883-2016.
Анотація:
Abstract. Aerosols of the volcanic degassing plumes from Mt. Etna and Mt. Stromboli were probed with in situ instruments on board the Deutsches Zentrum für Luft- und Raumfahrt research aircraft Falcon during the contrail, volcano, and cirrus experiment CONCERT in September 2011. Aerosol properties were analyzed using angular-scattering intensities and particle size distributions measured simultaneously with the Polar Nephelometer and the Forward Scattering Spectrometer probes (FSSP series 100 and 300), respectively. Aerosols of degassing plumes are characterized by low values of the asymmetry parameter (between 0.6 and 0.75); the effective diameter was within the range of 1.5–2.8 µm and the maximal diameter was lower than 20 µm. A principal component analysis applied to the Polar Nephelometer data indicates that scattering features of volcanic aerosols of different crater origins are clearly distinctive from angular-scattering intensities of cirrus and contrails. Retrievals of aerosol properties revealed that the particles were "optically spherical" and the estimated values of the real part of the refractive index are within the interval from 1.35 to 1.38. The interpretation of these results leads to the conclusion that the degassing plume aerosols were porous with air voids. Our estimates suggest that aerosol particles contained about 18 to 35 % of air voids in terms of the total volume.
Дисертації з теми "Aerosol origins":
1
Taubman, Brett F. "Airborne characterization of regional aerosol origins and optical properties." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1893.
Анотація:
Thesis (Ph. D.)--University of Maryland, College Park, 2004.Thesis research directed by: Chemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
2
Velazquez, Garcia Alejandra. "Chemical and optical properties of particulate pollution in the Lille area, Northern France based on ATOLL observations." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2023. http://www.theses.fr/2023MTLD0001.
Анотація:
Le lien entre les propriétés optiques des aérosols fins et leur composition chimique n'est pas encore bien compris. Il a été étudié ici en utilisant des mesures in situ (spectromètre de masse d'aérosol, aethalomètre et néphélomètre) réalisées sur la plateforme ‘ATmospheric Observations in liLLe’ de 2016 à 2020. On a pu observer des aérosols très absorbants et une saisonnalité marquée pour la contribution massique du nitrate d'ammonium (AN) au printemps. Nous avons montré que l'AN (35%) et les aérosols carbonés (51%) prédominent dans l’extinction du rayonnement à 525 nm. Enfin, une nouvelle approche combinant ces mesures in situ à des rétrotrajectoires, et des inventaires d'émissions ont révélé une diminution du carbone brun (BrC) dans les 24 heures suivant son émission, même en hiver, ce qui implique une probable sous-estimation systématique de la contribution attribuée au chauffage résidentiel (lié à la présence de BrC) dans l'absorption des aérosols de la régionThe link between fine aerosol optical properties and their chemical composition is not yet well understood, and was investigated using long-term in situ observations performed at the “ATmospheric Observations in liLLe” platform from 2016 to 2020 using a combination of aerosol mass spectrometer, aethalometer, and nephelometer. Highly absorbing aerosols and a marked seasonality of the mass contribution of ammonium nitrate (AN) in spring were observed. We evidence that AN (35%) and carbonaceous aerosols (51%) are predominant regarding light extinction at 525 nm. Besides, a novel approach combining these in situ measurements to backtrajectories and emission inventories identifies a Brown Carbon (BrC) decrease within 24 hours after emission even during wintertime, pointing at a likely systematic underestimation of the contribution of residential heating (identified by the presence of BrC) to the aerosol absorption in the region
3
Engvall, Ann-Christine. "Properties and origin of arctic aerosols /." Stockholm : Department of Meteorology, Stockholm university, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-7524.
4
Leung, Fok-Yan Thomas Hoffmann Michael R. "Elucidation of the origins of stratospheric sulfate aerosols by isotopic methods /." Diss., Pasadena, Calif. : California Institute of Technology, 2003. http://resolver.caltech.edu/CaltechETD:etd-05292003-144531.
5
Garbaras, Andrius. "Study of aerosol particle origin and dispersion by isotope ratio mass spectrometry." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110705_095446-72095.
Анотація:
The development of industry, transport, agriculture and power engineering inevitably create problems related to the impact of generated waste on the environment as well as other undesirable processes. The atmosphere is the main component of the Earth’s climate system because changes occurring due to the human economic activity result in serious environmental impacts in all components of the ecosystem as well as the Earth’s climate self-regulation system is disturbed. The objective of this work was to investigate the origin, sources and formation of organic compounds and black carbon in atmospheric aerosol particles and to develop new research methods. To attain this objective the following tasks have been formulated: Development of the identification method for the aerosol origin and source by investigating the carbon isotope mass ratios, illustration of possibilities of the carbon isotope ratio method by identifying the aerosol particle origin during the air mass long-range transport at the Preila Environmental pollution research station, investigation of variation of the black carbon amount in aerosol particles in the diesel engine exhaust depending on the engine working parameters and fuel composition, investigation of the carbon isotope ratio variation in natural aerosol depending on the aerosol particle size distribution, determination of the partial contribution of natural and anthropogenic particles in aerosol by investigation of stable carbon and radiocarbon isotope... [to full text]Žemės atmosfera yra svarbiausia klimato sferos dalis ir jautriausias antropogeninei taršai aplinkos sandas. Atmosferoje vykstantys procesai pakeičia ekosistemose per šimtmečius nusistovėjusius procesus – stebime įvairias globalinės klimato kaitos sukeltas pasekmes. Mokslinė šio darbo idėja nukreipta į įvairiapusį atmosferos aerozolio dalelių savybių ir prigimties tyrimą bei tyrimo metodų plėtrą, pasiremiant naujausiomis aplinkotyros mokslo žiniomis, akcentuojant pastarojo dešimtmečio masių spektrometrijos pasiekimus. Šio darbo tikslas yra organinių medžiagų ir juodosios anglies atmosferos aerozolio dalelėse kilmės, aerozolio sudėties ir formavimosi tyrimai bei naujų tyrimo metodų plėtra. Darbe eksperimentiškai įrodyta, kad anglies izotopų santykis antropogeninės kilmės aerozolio dalelėse atitinka deginamo kuro izotopų santykį ir šis parametras tinka, identifikuojant aerozolio dalelių šaltinį. Šis izotopų santykis, kaip metodinė priemonė, buvo panaudotas tiriant įvairios prigimties aerozolio sudėtį, savybes ir kilmę. Tiriant aerozolio daleles tolimojoje oro pernašoje stebėjome elementinės anglies δ13C verčių kaitą akumuliacinėje modoje nuo -22,9 ‰ iki -26,3 ‰, organinės anglies δ13C = -28 ‰. Iš δ13C verčių nustatyta, jog elementinės anglies pirmtakai aerozolio dalelėse buvo degimo produktai, organinės anglies šaltinis – lakūs organiniai junginiai iš augalų. Vietinės kilmės dalelių, didesnių už 1 μm, stebėta karbonatinė komponentė. Apjungus masių ir izotopų santykių masių... [toliau žr. visą tekstą]
6
Garbarienė, Inga. "Origin, chemical composition and formation of submicron aerosol particles in the atmosphere." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140520_134625-72680.
Анотація:
The objective of the work was to investigate physical and chemical properties and sources of the atmospheric aerosol particles in the submicron fraction by combining different analytical techniques. The dependence of concentrations of organic and elemental carbon in different air masses was determined and the contribution of regional and local sources to the net aerosol particle pollution was estimated. Analysis of the size distribution of carbonaceous aerosol particles in background and urban areas was performed. Biogenic organic aerosol made up 15 % of the organic aerosol mass at the Preila atmospheric pollution research station, but in the North Atlantic air masses this factor was up to 50 %. Aerosol and stable isotope ratio mass spectrometry has revealed that traffic is the primary source of aerosol particles in the city, while biomass burning is the primary source at the Rūgšteliškis background station. It was determined that secondary anthropogenic organic compounds were dominating (76 %) in Vilnius, while in Rūgšteliškis secondary biogenic organic compounds made up 50 % of the total organic aerosol mass. The influence of the long-range air mass transport on the local origin aerosol particle formation and transformation has been evaluated and it has been shown that volcanic aerosol particles can significantly change the concentration, chemical composition and size distribution of local aerosol particles in the submicron range.Disertacija skirta smulkiosios aerozolio dalelių frakcijos šaltinių, fizikinių ir cheminių savybių įvertinimui kompleksiškai apjungiant įvairius tyrimo metodus. Darbe susieti elementinės ir organinės anglies koncentracijų pokyčiai su tolimąja oro masių pernaša, įvertinta regiono bei vietinių šaltinių įtaka bendrai aerozolio dalelių taršai. Aprašyti anglies turinčių aerozolio dalelių pasiskirstymai pagal dydį foninėse vietovėse ir miesto aplinkoje. Naudojant aerozolio masių spektrometrą Preilos atmosferos užterštumo tyrimų stotyje buvo identifikuotas biogeninis organinių medžiagų šaltinis, kuris vidutiniškai sudaro 15 % nuo organinių medžiagų masės, tačiau Šiaurės Atlanto oro masėje biogeninių medžiagų indėlis siekia net 50 %. Atlikus kompleksinę aerozolio ir stabiliųjų anglies izotopų masių spektrometrinę analizę buvo nustatyta, kad pirminis anglies turinčio aerozolio dalelių šaltinis mieste yra autotransportas, o Rūgšteliškio foninėje vietovėje – biomasės deginimas. Taip pat buvo nustatyta, kad Vilniuje dominavo antropogeninės antrinės organinės medžiagos (76 %), o Rūgšteliškyje vyravo biogeninės antrinės organinės medžiagos (apie 50%). Vertinant tolimosios oro masių pernašos įtaką vietinės kilmės aerozolio dalelių formavimuisi ir kaitai, buvo nustatyta, kad vulkaninės kilmės aerozolio dalelės turi įtakos submikroninės aerozolio dalelių frakcijos koncentracijai, cheminei sudėčiai ir pasiskirstymui pagal dydį.
7
Finessi, Emanuela <1977>. "Chemical characterization of atmospheric secondary organic aerosol of biogenic and anthropogenic origin." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2808/1/Finessi_Emanuela_tesi.pdf.
Анотація:
The main objective of this thesis was the chemical characterization of synthetic secondary organic aerosol (SOA) produced from atmospherically relevant anthropogenic and biogenic VOCs during reaction chamber experiments. In parallel, the resulting chemical features of these laboratory-SOA were used to interpret the composition of ambient samples of atmospheric fine particulate matter collected at several sites in Europe, in order to determine the fraction of ambient aerosol organic mass accounted for by biogenic and anthropogenic SOA.
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Finessi, Emanuela <1977>. "Chemical characterization of atmospheric secondary organic aerosol of biogenic and anthropogenic origin." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2808/.
Анотація:
The main objective of this thesis was the chemical characterization of synthetic secondary organic aerosol (SOA) produced from atmospherically relevant anthropogenic and biogenic VOCs during reaction chamber experiments. In parallel, the resulting chemical features of these laboratory-SOA were used to interpret the composition of ambient samples of atmospheric fine particulate matter collected at several sites in Europe, in order to determine the fraction of ambient aerosol organic mass accounted for by biogenic and anthropogenic SOA.
9
Gérard, Violaine. "Surfactants in atmospheric aerosols and their role on cloud formation." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1216/document.
Анотація:
Les nuages sont essentiels dans le cycle de l'eau et dans le budget climatique mais certains aspects de leur formation sont encore incompris. La théorie de Köhler prédit que les surfactants devraient favoriser l'activation des particules en goutte de nuage alors que les modèles actuels les considèrent comme négligeables. Au début de ce travail de thèse, quelques études commençaient à démontrer le contraire mais des preuves du rôle de ces composés dans l'atmosphère étaient encore manquantes, d'où l'objectif de ce travail de thèse. Le développement d'une méthode pour déterminer la concentration en surfactants dans les aérosols a conduit aux premières courbes de tension de surface de surfactants atmosphériques dans des aérosols PM2.5 côtiers (Suède), et à l'identification du ratio C/CMC comme paramètre clé contrôlant l'efficacité des aérosols à former des nuages. Une seconde étude a révélé des corrélations fortes entre la présence de nuages et les propriétés intrinsèques des surfactants dans des aérosols PM1 boréaux (Finlande), démontrant pour la première fois le rôle des surfactants dans la formation des gouttes de nuage à partir d'observations directes dans l'atmosphère. Les résultats prédisent un nombre de noyaux de condensation en moyenne quatre fois plus important que lorsque les effets des surfactants étaient négligés, montrant l‘importance d'inclure l'effet des surfactants dans les modèles prédictifs. Cette importance a été confirmée en laboratoire par des expériences sur des gouttes individuelles microniques par l'augmentation de leur taille en présence de surfactants. Enfin, les observations à partir des différentes études indiquent une origine biologique des surfactants dans les aérosols atmosphériquesClouds are essential components of the Earth’s hydrological system and climate but some aspects of their formation are still not completely understood. In particular, although Köhler theory predicts that surfactants should enhance cloud droplet activation, current models consider this role negligible. At the time of this PhD work, a few studies had started to demonstrate the contrary but atmospheric evidence for the role of these compounds was still missing and very little was known about their atmospheric concentrations, sources, and mechanism of action. The objective of this PhD work was to investigate these aspects. A method was developed to quantify surfactant concentrations in aerosols. Its application led to the first absolute atmospheric surfactants’ surface tension curves, in coastal PM2.5 aerosols in Sweden, and to the identification of the ratio C/CMC as the key parameter controlling the cloud-forming efficiency of aerosols. A second study revealed strong correlations between cloud occurrence and intrinsic surfactant properties in boreal PM1 aerosols in Finland, demonstrating for the first time the role of surfactants in cloud formation from direct atmospheric observations. The results predicted Cloud Condensation Nuclei numbers four times larger on average than when neglecting surfactant effects, showing the importance of including surfactant effects in cloud predictions models. The role of surfactants inferred from macroscopic measurements was confirmed by laboratory experiments on individual micron-sized droplets showing an increase of droplet growth in the presence of surfactants. Finally, observations from the different field studies indicated a biological origin for the surfactants present in atmospheric aerosols
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Rinehart, Lynn Rebecca. "The origin of polar organic compounds in ambient fine particulate matter." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3210293.
Книги з теми "Aerosol origins":
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B, Toon O., Turco Richard P, and United States. National Aeronautics and Space Administration., eds. Origin of condensation nuclei in the springtime polar stratosphere. [Washington, DC: National Aeronautics and Space Administration, 1995.
Частини книг з теми "Aerosol origins":
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Gilardoni, Stefania, and Sandro Fuzzi. "Chemical Composition of Aerosols of Different Origin." In Atmospheric Aerosols, 183–221. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2016. http://dx.doi.org/10.1002/9783527336449.ch4.
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Ito, Tomoyuki. "Nature and Origin of Antarctic Submicron Aerosols." In Ice Core Studies of Global Biogeochemical Cycles, 23–38. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-51172-1_2.
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Hoffmann, T. "Organic Aerosols: Origin, Composition and Influence on Tropospheric Processes." In Transport and Chemical Transformation in the Troposphere, 132–42. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-56722-3_23.
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Ramirez, Sandra I., Rafael Navarro-Gonzalez, Patrice Coll, and François Raulin. "Chemical Characterization of Aerosols in Simulated Planetary Atmospheres." In Cellular Origin and Life in Extreme Habitats and Astrobiology, 281–85. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-94-007-1003-0_59.
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Navarro-Gonzalez, Rafael. "Production of Organic Gases and Aerosols by Electrical Activity in Titan’s Tropospheric Clouds." In Exobiology: Matter, Energy, and Information in the Origin and Evolution of Life in the Universe, 313–16. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5056-9_44.
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Cholakian, Arineh, Matthias Beekmann, Guillaume Siour, Hervé Petetin, Agnes Borbon, Paola Formenti, Evelyne Freney, et al. "A Modelling Perspective of the Summer 2013 and 2014 ChArMEx/SAFMED Chemistry Intensive Campaigns: Origin of Photo-Oxidant and Aerosol Formation over the Western Mediterranean." In Springer Proceedings in Complexity, 85–90. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-24478-5_14.
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Calvert, Jack G., Roger Atkinson, Karl H. Becker, Richard M. Kamens, John H. Seinfeld, Timothy J. Wallington, and Greg Yarwood. "Aerosol Generation In Atmospheric Oxidation Of Aromatic Hydrocarbons." In The Mechanisms Of Atmospheric Oxidation Of Aromatic Hydrocarbons, 311–45. Oxford University PressNew York, NY, 2002. http://dx.doi.org/10.1093/oso/9780195146288.003.0008.
Анотація:
Abstract Atmospheric aerosol in virtually all areas of the troposphere, but especially in urban areas, contains a significant fraction of carbonaceous material. Atmospheric particulate carbonaceous material is composed of a complex mixture of substances, frequently classified in two main fractions: elemental carbon (EC) and organic carbon (OC). Elemental, or black carbon is a primary pollutant, emitted directly as a result of the combustion of fossil and biomass fuels. Particulate organic carbon, a complex mixture of hydrocarbons and oxygenated hydrocarbons, has both primary and secondary origins. Primary particulate OC is emitted during combustion of fuels, cooking of meat, and so on, whereas secondary particulate OC results from gas-to-particle conversion of volatile organic compounds in the atmosphere. This secondary particulate OC is usually referred to as secondary organic aerosol (SOA).
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Ottar, Brynjulf, and Jozef M. Pacyna. "Origin and characteristics of aerosols in the Norwegian Arctic." In Arctic Air Pollution, 53–68. Cambridge University Press, 1987. http://dx.doi.org/10.1017/cbo9780511565496.007.
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Acheson, D. J. "Vortex motion." In Elementary Fluid Dynamics, 157–200. Oxford University PressOxford, 1990. http://dx.doi.org/10.1093/oso/9780198596608.003.0005.
Анотація:
Abstract We mentioned in §1.1 how the shedding of a starting vortex is essential to the generation of lift on an aerofoil, and we now investigate why this should be so. Consider the situation at a time t after the start. Vorticity and viscous forces will be confined to (i) a thin boundary layer on the aerofoil, (ii) a thin wake, and (iii) the rolled-up ‘core’ of the starting vortex, as indicated by the shading in Fig. 5.2. Consider now a dyed circuit abcda which is large enough to have been clear of all these regions since the start of the motion. As the original state was one of rest the circulation round that circuit was originally zero.
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Prakash Sinha, Tej, Brunda RL, Sakshi Yadav, and Sanjeev Bhoi. "Practice Changing Innovations for Emergency Care during the COVID-19 Pandemic in Resource Limited Settings." In Origin and Impact of COVID-19 Pandemic Originating From SARS-CoV-2 Infection Across the Globe [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98293.
Анотація:
COVID-19 has affected millions worldwide. To combat the infectious pandemic in resource limited settings, healthcare workers and techies have come up with multiple innovations. Nations with scarcity of resources have resorted to innovative strategies involving optimal utilization and repurposing of available commodities to overcome the demand–supply mismatch. Emergency rooms overburdened with diseased population are resorting to local innovative ideas to overcome obstacles in COVID-19 patient care. Point of care testing strategies in emergency rooms, sampling booths to reduce Personal Protective Equipment (PPE) use, disinfection strategies such as tunnel disinfection and local production of sanitizers, face masks/shields, aerosol containment chambers, novel triage protocols, telehealth care strategies reaching out to remote population and utilizing point for care ultrasound for resuscitation are few of the novel innovations which have benefitted medical fraternity and patient care in testing times. Medical innovations have emerged as the positive outcome of otherwise devastating COVID-19 pandemic. These practice changing innovations could also prove beneficial in future infectious pandemics.
Тези доповідей конференцій з теми "Aerosol origins":
1
Stefanie, Horatiu, Andrei Radovici, Alexandru Mereuta, Horia Camarasan, and Nicolae Ajtai. "DETECTION OF LOCAL AND LONG-RANGE TRANSPORTED AEROSOL INTRUSIONS OVER CLUJ-NAPOCA, ROMANIA USING MULTIWAVELENGTH LIDAR MEASUREMENTS IN SPRING 2022." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/2.1/s10.34.
Анотація:
It is well known that atmospheric aerosols have both a direct and an indirect impact on the Earth's systems and have natural or anthropogenic origins. In this paper we present the results of the 2022 spring-time lidar measurements conducted within the European Aerosol Research Lidar Network (EARLINET) using a multi-wavelength Raman and depolarization LIDAR system operated in Cluj-Napoca, Romania. The Cluj-Napoca lidar system (CLOP) emission is based on a Nd-YAG laser Continuum INLITE II-30, which has a repetition rate of 30 Hz. The radiation at 1064, 532, and 355 nm is simultaneously emitted into atmosphere. The backscattered radiation is collected by a Cassegrain type telescope with a focal length of 1500 mm. The signal detection unit has a total of 6 detection channels, 4 channels for the elastically backscattered radiation at 1064, 532 (cross and parallel), and 355 nm and 2 channels for the Raman radiation backscattered by nitrogen molecules at 607 and 387 nm. This type of system meets the requirements of the EARLINET network and is suitable to provide reliable data on optical parameters for aerosol characterization. The reference period for the observations was in accordance with EARLINET�s fixed measurements schedule. The preliminary results indicated the presence of both natural (mineral dust) and anthropogenic (resulted from seasonal biomass burning) aerosols originated from local sources or subject of long-range transport (LRT).
2
Hansson, H. C. "The free tropospheric aerosol, origin and properties." In The 15th international conference on nucleation and atmospheric aerosols. AIP, 2000. http://dx.doi.org/10.1063/1.1361957.
3
B S, Dakshayini, Kishore Babu Kancherla, Benjamin Raju, and Debiprosad Roy Mahapatra. "Assessing the Structural Feasibility and Recyclability of Flax/PLA Bio-Composites for Enhanced Sustainability." In AeroCON 2024. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-26-0407.
Анотація:
<div class="section abstract"><div class="htmlview paragraph">Bio-composites have gained significant attention within the aerospace industry due to their potential as a sustainable solution that addresses the demand for lightweight materials with reduced environmental impact. These materials blend natural fibers sourced from renewable origins, such as plant-based fibers, with polymer matrices to fabricate composite materials that exhibit desirable mechanical properties and environmental friendliness. The aerospace sector's growing interest in bio-composites originates from those composites’ capacity to mitigate the industry's carbon footprint and decrease dependence on finite resources.</div><div class="htmlview paragraph">This study aims to investigate the suitability of utilizing plant-derived flax fabric/PLA (polylactic acid) matrix-based bio-composites in aerospace applications, as well as the recyclability potential of these composites in the circular manufacturing economy. The bio-composite laminate is produced through a compression molding process involving interleaved layers of PLA and flax fiber mats. We discuss the manufacturing technique, mechanical behavior, thermal characteristics properties of the bio-composite. A thorough comparison is drawn between these properties and those of similar bio-composites. Moreover, the study emphasizes the recycling of these bio-composites using mechanical milling, and their subsequent use as additives in the original fiber mat laminated composites. A comprehensive evaluation is conducted, contrasting the attributes of the original laminate with those of the laminate containing recycled additives.</div><div class="htmlview paragraph">The outcomes of this study will contribute to understanding and assessing the sustainability of bio-based polymer applications. By examining the performance of flax/PLA bio-composites in aerospace composite material qualification settings and investigating their recyclability, this research reveals the viability as an eco-friendly alternative in the aerospace industry, aligning with the industry's ongoing efforts to adopt greener practices and materials.</div></div>
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Kurudimath, Kottresh, Salil Kanj Jalan, and Jancy Rose. "Fast Coupled Load Analysis through Reanalysis Technique: Formulation and Demonstration on Sample Problems." In AeroCON 2024. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-26-0459.
Анотація:
<div class="section abstract"><div class="htmlview paragraph">Design of Launch vehicle is multidisciplinary process in which designers of all the domain of engineering like mechanical, electronics, chemical, materials etc contribute. For the mechanical design, Coupled Load Analysis (CLA) is statutory requirement without which no launch vehicle will be allowed to fly.</div><div class="htmlview paragraph">In CLA, launch vehicle is subjected to various loads during its flight due to engine thrust depletion / shut-off, thrust oscillation, wind and gust, maneuvering loads. In aerospace industry a standard CLA is performed by generating the mathematical model of launch vehicle and coupling it with reduced mathematical model of payload and applying the boundary conditions. A CLA is a time consuming process as several flight instances and load cases need to be considered along with generation of structural dynamic model at each time instants. For every new mission, the payloads are mission specific whereas the launch vehicle and the loads remain unchanged. To take advantage of this fact, a new method called “Fast CLA through Reanalysis technique” is proposed in the present paper.</div><div class="htmlview paragraph">Fast Coupled Load analysis eliminates the need to generate new coupled mathematical model of launch vehicle and payload in case only payload is changed for the new mission. The method uses system frequencies of the original system (launch vehicle + original payload), eigen vectors row corresponding to the launch vehicle original payload interface, internal points of original payload and external load application location and mass and stiffness matrix of the original and new payload to determine responses for the new payload without performing traditional CLA. This can be performed outside the finite element software. At present, formulation of the analysis is completed and tested for lumped parameter model which gives encouraging results. Methodology is being implemented for the full launch Vehicle.</div></div>
5
Tutsak, Ersin, Mohamed M. Mahfouz, and Imran Shahid. "Atmospheric Black Carbon over Qatar: Seasonal Variability and Source Apportionment." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2021. http://dx.doi.org/10.29117/quarfe.2021.0041.
Анотація:
The earth’s atmosphere contains minute particles suspended within it. These atmospheric particles influence the earth's radiation budget through their ability to absorb and scatter radiation. Black carbon (BC) is a type of carbonaceous particle, characterized by highly absorbing solar radiation. Unlike sulfate and sea-salt aerosols, black carbon causes positive radiative forcing due to its absorbing nature. With the accumulation of greenhouse gases in the atmosphere, the average global temperature increased by 1.09°C (IPCC, 2021), between 1850-1900 and the last decade. Since black carbon is one of the major light-absorbing components of aerosol, there is a need to assess BC concentration, their origin, and the contribution of both human-induced combustion and biomass burning emissions to BC levels. In this study, four-year measurements of aerosol absorption at seven wavelengths were investigated in order to determine the daily and seasonal behavior of black carbon and contribution of fossil fuel (FF) and biomass burning (BB) emissions to total BC mass concentration in a suburban area located north of Doha. The highest concentrations of BC were observed during the winter and the lowest values during the summer. The absorption coefficient (Babs) at 470 nm (950 nm) showed large daily variability, ranging from 7 (3) to 187 (95) Mm-1. The mean Babs at 470 nm and 950 nm for the full period were 55± 29 Mm -1 and 25 ± 13 Mm -1, respectively. Fossil fuel emissions were found to be the major source of BC levels. Nonetheless, the influence of biomass burning should not be disregarded. Future studies must be done to fully identify the enhanced absorption in shorter wavelengths.
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DeSha, Michael S. "Biological Aerosol Sensor Breadboard." In The European Conference on Lasers and Electro-Optics. Washington, D.C.: Optica Publishing Group, 1998. http://dx.doi.org/10.1364/cleo_europe.1998.cfj7.
Анотація:
In recent history, manmade and natural events have shown us the ever-present need for systems to monitor the troposphere for contaminates. These contaminants may take either a chemical or biological form, which determines the methods we use to monitor them. Monitoring the troposphere for biological contaminants is of particular interest to my organization. Whether manmade or natural, contaminants of a biological origin share a similar constitution: typically the aromatic amino acids tryptophan, phenylalanine, and tyrosine in varying amounts. All of these proteinaceous compounds have the capability to autofluoresce when exposed to ultraviolet radiation. This establishes the basis of the laser induced fluorescence (LIF) technique we use to detect biological contaminants. This technique can be employed in either point or remote detection schemes and is a valuable tool for discriminating proteinaceous from non-proteinaceous aerosols. For this particular presentation I am going to describe a breadboard point sensor I designed and fabricated to detect proteinaceous aerosols.
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Ljungkvist, Göran, Olof Beck, Karina Stein, Åsa Danielsson, Agneta Agge, Helene Friberg, Emilia Wiklund, et al. "Study on the origin and collection of exogenous compounds in exhaled breath aerosol particles." In Annual Congress 2015. European Respiratory Society, 2015. http://dx.doi.org/10.1183/13993003.congress-2015.pa2095.
8
Shaw, Sandeep Prasad, Adarsh Thakur, Thara Nair, and Raveendra KK. "Aerospace Vehicle Motion Simulation with Real-Time Telemetry Data." In AeroCON 2024. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-26-0483.
Анотація:
<div class="section abstract"><div class="htmlview paragraph">With regards to any aerospace mission, it is very useful to have awareness about the state of vehicle, i.e., the information about its position, velocity, attitude, rotational rates and other concerned data such as control surface deflections, landing gear touchdown, working of mechanisms and so on. The sensor data from the vehicle that is communicated to the ground can be difficult to perceive and analyze. A frame work for real-time motion simulation of an aerospace vehicle from onboard telemetry data is henceforth developed in order to improve the understanding about the current state of the mission and aid in real-time decision making if required. The telemetry data, that is transmitted through User Datagram Protocol (UDP), is received and decoded to usable format. The visualization software accepts the data in a fixed time interval and applies the required transformations in order to ensure one-to-one correspondence between actual vehicle and simulation. The transformations required for missions with various scope are formulated. Data handling scheme for low frequency data and data loss are also discussed. The importance of environment design emphasized, the 3D terrain is created from satellite imagery and heightmap or digital elevation model. The shader for volumetric atmosphere useful for surface to space missions, is created using an algorithm that simulated scattering of light in the atmosphere. For larger environments required for launch vehicle missions, a scaling scheme is worked out and is implemented in combination with the floating-origin algorithm to deal with the floating-point limitations posed by current generation graphic engines. Techniques such as quad-tree structures for level of detail (LOD) rendering are used for optimization of performance. Animation of flight events are rigged and get triggered based on flags in telemetry data. The developed framework was tested in critical demonstration missions for ISRO – The Reusable Launch Vehicle Landing Experiment (RLV-LEX) and Test Vehicle Demonstration Mission -1 (TV-D1). The framework can be used for a variety of missions such as launch vehicles, spacecrafts, UAVs and even landers & rovers.</div></div>
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Sandhu, Taranjeet, Ravi Aher, Ravi Soni, Nikhil Barsawade, Swapnil Kamthe, and Vijay Sajjan Phalle. "Elastomeric Swaging Finite Element Analysis Methodology to Evaluate Structural Integrity of Internal Swaged Joints." In AeroCON 2024. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-26-0428.
Анотація:
<div class="section abstract"><div class="htmlview paragraph">In applications demanding high performance under extreme conditions of pressure and temperature, a range of Mechanically Attached Fittings (MAFs) is offered by various Multinational Corporations (MNCs). These engineered fittings have been innovatively designed to meet the rigorous requirements of the aerospace industry, offering a cost-effective and lightweight alternative to traditional methods such as brazing, welding, or other mechanically attached tube joints.</div><div class="htmlview paragraph">One prominent method employed for attaching these fittings to tubing is through Internal Swaging, a mechanical technique. This process involves the outward formation of rigid tubing into grooves within the fitting. One of the methods with which this intricate operation is achieved is by using a drawbolt - expander assembly within an elastomeric swaging machine. Traditionally, elastomeric swaged joints find extensive application among Aerospace Industry Original Equipment Manufacturers (OEMs) and are compatible with materials like Titanium, Aluminum, and Stainless Steel, accommodating various tube wall thicknesses.</div><div class="htmlview paragraph">To optimize the design of elastomeric swaged joints and manufacturing process, a Finite Element Analysis (FEA) methodology has been developed utilizing the licensable Abaqus software. This methodology simulates the intricate cold forming operation of elastomeric swaging, thereby establishing a robust correlation between FEA and physical testing results. This correlation addresses critical quality parameters such as structural integrity and mechanical strength, aiding in the optimization of swaging parameters, minimizing testing requirements, and significantly reducing the overall lead time for the development of new swaged joints.</div></div>
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C, Carunaiselvane, and Rajesh Kumar. "Comparative Analysis of Axial Flux and Radial Flux Motors for UAV Propulsion: Design and Suitability Assessment." In AeroCON 2024. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2024. http://dx.doi.org/10.4271/2024-26-0467.
Анотація:
<div class="section abstract"><div class="htmlview paragraph">In the architecture of an Unmanned Aerial Vehicle (UAV), a crucial component responsible for the propulsion system is the electric motor. Over the years, different types of electric motors, including Brushless Direct Current (BLDC), have supported the UAV’s propulsion system in diverse configurations. However, in the context of flux flow, the Radial Flux Permanent Magnet Motor (RFPMM) has been given more priority than the Axial Flux Permanent Magnet Motor (AFPMM) due to its sustainability in design and construction. Nevertheless, the AFPMM boasts higher speed, power density, lower weight, and greater efficiency than the RFPMM, because of its shorter flux path and the absence of end-turn winding. Therefore, this paper focuses to conduct a suitability analysis of an AFPMM as a shaft-connected propeller-mounted motor, with the intention of replacing the RFPMM in UAV applications. The design of the AFPMM, incorporating topologies featuring a one-rotor, one-stator configuration, is considered. In this research, the physical dimensions of an AFPMM required to meet performance parameters are derived using systematic analytical equations. Furthermore, the design is executed using a multi-physics simulation tool to analyse the electromagnetic behaviour of the model. To validate the designed model and compare its characteristics, a prototype of BLDC RFPMM with similar output performance parameters is selected. The operating parameters are tested for compliance with the recommended output characteristics of the Original Equipment Manufacturer (OEM). Through reverse engineering, the design dimensions are obtained, and the electromagnetic behaviour is analysed using a multi-physics simulation tool. Moreover, based on the performance characteristics of the RFPMM, the design dimensions of the AFPMM are determined using sizing equations and assumed design variables. The suitability analysis, focusing on UAV behaviour is scrutinized to identify the most appropriate electric motor for ensuring the sustainable and efficient operations.</div></div>
Звіти організацій з теми "Aerosol origins":
1
Dawson, Greer, Gai Moore, Anton du Toit, Rebecca Gordon, Susie Thompson, Haitham Taha, and Shallu Sharma. Update: What is known about aerosol transmission of SARS-CoV-2? The Sax Institute, October 2020. http://dx.doi.org/10.57022/onai3530.
Анотація:
This Evidence Snapshot is an updated rapid review of current knowledge about aerosol transmission of COVID-19. The original review was completed in August 2020 and this updated review in October 2020. The updated review found that the weight of evidence was that aerosol transmission of SARS-CoV-2 does occur. Five reviews found that the virus may spread as an aerosol. Experimental studies demonstrated aerosolisation of the virus with persistence from 90 minutes to 16 hours, and evidence for horizontal transmission was found for ranges from two to eight metres. Environmental sampling studies typically found viral RNA both in the air and on air vents. Eight out of ten investigations of outbreaks reviewed found that transmission occurred without close direct contact. Risk of transmission was thought to be associated with shared indoor space, closed air recirculation and singing. Eighteen articles were reviewed in the updated report in addition to the nineteen articles in the original report, for a total of thirty-seven articles.
2
Vreeke, Shawna. Investigating the Origins of Toxins Present in Electronic Cigarette Aerosols. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.7211.
3
Miley, Harry, Paul Eslinger, and Judah Friese. Examining Nuisance Aerosol Detections in Light of the Origin of the Screening Process (November 2021). Office of Scientific and Technical Information (OSTI), December 2021. http://dx.doi.org/10.2172/1843271.
4
Fu, Yuqi, Shuo Liu, Weijie Chen, Guohui Ruan, and Li Liu. Assessing the impact of ventilation on the potential airborne infection risk in hospital lung function room. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau541663876.
Анотація:
Controlling the spread of respiratory infectious diseases in healthcare settings is important to avoid nosocomial infection. We utilized computational fluid dynamics (CFD) simulation, real-time carbon dioxide (CO2) monitoring, microorganism culturing, and microorganism sequencing to quantitatively assess the exposure risk of healthcare workers to infectious respiratory particles (IRPs) in one lung function room under two ventilation configurations. The original ventilation system supplied 2 air changes per hour (ACH) for fresh air and 2 ACH for recirculated air, while the retrofitted ventilation system supplied 6 ACH of fresh air. Indoor CO2 concentration and microorganism concentration decreased after the retrofit. The ventilation modification significantly improved the discharge efficiency for 5 μm IRPs and 50 μm IRPs. The intake fraction of 5 μm aerosols and 50 μm aerosols for HCW decreased by 0.005% and 0.006%, respectively. This study also reviewed the effectiveness of the above methods when evaluating building retrofit.