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1

Wang, Shuo. "Retrieval of Aerosol Chemical Composition based on aerosol optical properties." Thesis, Littoral, 2020. https://tel.archives-ouvertes.fr/tel-03178823.

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La composition chimique des aérosols permet de mieux comprendre leurs interactions avec le changement climatique et la santé humaine. La composition chimique des aérosols est étroitement liée aux propriétés optiques. Actuellement, les propriétés optiques des aérosols sont mesurées, intégrées ou non sur la colonne atmosphérique, à une échelle globale. Le développement d'algorithmes permettant de déterminer, à une résolution spatiale et temporelle élevée, la composition chimique des aérosols à partir de leurs propriétés optiques est essentiel. Ce travail de thèse vise à tester et à améliorer les méthodes actuelles de classification et d'estimation de la composition chimique des aérosols. (1) Méthodes basées sur le coefficient d'Ǻngström (AE) : ces méthodes s'appuient sur la dépendance spectrale du coefficient de diffusion (SAE) et d'absorption (AAE). En effet, de nombreuses recherches distinguent les différents types d'aérosols en fonction de leur SAE et AAE. Afin de déterminer des valeurs seuils des SAE et AAE pour différents aérosols absorbants, la dépendance spectrale du SAE et AAR en fonction de la taille des particules, l'épaisseur relative d'une éventuelle couche surfacique et les longueurs d'ondes choisies pour le calcul. Les résultats montrent que SAE et AAE dépendent fortement des longueurs d'onde utilisées et sont également fortement affectés par la taille de l'aérosol. Les différents types de particules peuvent exister dans l'atmosphère dans les mêmes classes de taille et dans ce cas, SAE et AAE ne peuvent pas être utilisés pour distinguer efficacement ces différents composants.(2) Méthodes basées sur k : le but de ces méthodes est d'estimer la concentration massique des différents composants de l'aérosol à partir de la paie imaginaire de l'indice de réfraction (CRI, m=n + k i). A partir des indices de réfraction et de la variation spectrale de l'albédo à diffusion unique (dSSA), reportés par le réseau AERONET, la variation de la composition chimique des aérosols intégrée sur la colonne a été estimée puis comparée à la distribution saisonnière des émissions d'aérosols couplée au transport régional pendant différentes saisons. Cette comparaison montre des résultats très encourageants même si les compositions chimiques sont sensiblement différentes (intégrées sur la colonne et estimée en surface). La validation de cette méthode nécessite donc de disposer de jeux de mesures de la composition chimique plus comparables.(3) Méthode de k-p : afin de faciliter la distinction entre les poussières minérales (MD) et le carbone organique (OC), une nouvelle méthode basée sur la partie imaginaire du CRI (k) et de la densité des aérosols (p) a été développée. L'application de cet algorithme sur des données (propriétés optiques et physiques) recueillies lors d'une campagne d'observation à Shouxian permet d'obtenir la variation de la composition chimique des aérosols en temps réel. La composition chimique de l'aérosol estimé par cette méthode est cohérente avec les résultats des mesures in-situ. La concentration massique des MD est la moins bien estimée par cet algorithme (R²=0.43) probablement dur à une plus grande incertitude dans la mesure<br>Aerosol chemical composition is an essential factor to better understand aerosol interactions with climate change, atmospheric environment and human health. Aerosol optical property is closely associated to chemical composition. Nowadays, vertical and global aerosol optical properties are measured. Development of aerosol chemical composition retrieval algorithm based on optical properties is essential to derive aerosol chemical composition with high spatial and temporal resolution. This thesis aims to test and improve the present methods for aerosol chemical composition classification and retrieval. (1) Ǻngström Exponent (AE) methods : these methods are based on Scattering (SAE) ans Absorption (AAE) AE to derive absorption coefficients by different aerosols or distinguish aerosol types, but many studies used different SAE and AAE values or thresholds. To understand these discrepancies, SAE and AAE dependencies to particle size, relative coating thickness and wavelength pairs were studied for different absorbing aerosols. The results reveal that SAE and AAE depend on wavelength pairs used for calculations and are also greatly influenced by aerosol size, thus knowledge of aerosol size information could reduce the uncertainty of calculating absorption coefficients by different aerosols using AAE. As aerosol particles could exist within the same size bin, SAE and AAE cannot be used to distinguish different compositions effectively by setting thresholds.(2)k-based methods : these methods aim to retrieve the mass concentrations of different aerosol compounds based on the imaginary part of Complex Refractive Index (CRI, m=n + k i). For the application and examination of the k-based methods, columnar aerosol chemical compositions were retrieved based on CRI and spectral variation of Single Scattering Albedo (dSSA) using long-term AERONET measurements. Dependence of retrieved columnar aerosol chemical compositions on regional transported was investigated in different seasons. This result is comparable to seasonal aerosol emission distribution and transport process. But the reliable aerosol chemical composition at the same level is still needed to verify algorithm. (3) k-p method : to tackle the difficulty to distinguish Organic Carbon (OC), from Mineral Dust (MD), a new method based on CRI imaginary part (k) and aerosol density (p) was developed. This algorithm was used to obtain the real-time aerosol chemical composition varation during an observation campaign in Shouxian. The retrieved aerosol chemical compositions were consistent with in-situ measurements.The weaker agreement (R²=0.43) of MD compared to the other species is due to the larger uncertainties from retrievals and measurements
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2

Gilbertson, Sarah Elizabeth. "Aerosol Gel production via controlled detonation of liquid precursors." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/1101.

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3

Cross, Eben Spencer. "Sources and transformations of atmospheric aerosol particles." Thesis, Boston College, 2008. http://hdl.handle.net/2345/971.

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Thesis advisor: Paul Davidovits<br>Aerosol particles are an important component of the Earth-Atmosphere system because of their influence on the radiation budget both directly (through absorption and scattering) and indirectly (through cloud condensation nuclei (CCN) activity). The magnitude of the raditaive forcing attributed to the direct and indirect aerosol effects is highly uncertain, leading to large uncertainties in projections of global climate change. Real-time measurements of aerosol properties are a critical step toward constraining the uncertainties in current global climate modeling and understanding the influence that anthropogenic activities have on the climate. The objective of the work presented in this thesis is to gain a more complete understanding of the atmospheric transformations of aerosol particles and how such transformations influence the direct and indirect radiative effects of the particles. The work focuses on real-time measurements of aerosol particles made with the Aerodyne Aerosol Mass Spectrometer (AMS) developed in collaboration with the Boston College research group. A key feature of the work described is the development of a lightscattering module for the AMS. Here we present the first results obtained with the integrated light scattering – AMS system. The unique and powerful capabilities of this new instrument combination are demonstrated through laboratory experiments and field deployments. Results from two field studies are presented: (1) The Northeast Air Quality Study (NEAQS), in the summer of 2004, conducted at Chebogue Point, Nova Scotia and (2) The Megacity Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in and around Mexico City, Mexico in March of 2006. Both field studies were designed to study the transformations that occur within pollution plumes as they are transported throughout the atmosphere. During the NEAQS campaign, the pollution plume from the Northeastern United States was intercepted as it was transported towards Europe. In this study, particles were highly processed prior to sampling, with residence times of a few days in the atmosphere. The MILAGRO campaign focused on the evolution of the Mexico City plume as it was transported north. During this study, regional and locally emitted particles were measured with residence times varying from minutes to days in the atmosphere. In both studies, the light scattering – AMS system provided detailed information about the density and composition of single particles, leading to important insights into how atmospheric processing transforms the particle properties. In Mexico City, the light scattering-AMS system was used for the first time as a true single particle mass spectrometer and revealed specific details about the atmospheric processing of primary particles from combustion sources.To quantify the radiative effects of the particles on climate, the processing and ultimate fate of primary emissions (often containing black carbon or soot) must be understood. To provide a solid basis for the interpretation of the data obtained during the field studies, experiments were conducted with a well characterized soot generation-sampling system developed by the Boston College research group. The laboratory soot source was combined with the light scattering – AMS system and a Cloud Condensation Nuclei Counter (CCNC) to measure the change in cloud-forming activity of soot particles as they are processed in the atmosphere. Because of the importance of black carbon in the atmosphere, several instruments have been developed to measure black carbon. In July of 2008, an intercomparison study of 18 instruments was conducted in the Boston College laboratory, with soot particles produced and processed to mimic a wide range of atmospherically-relevant conditions. Transformations in the physical, chemical, and optical properties of soot particles were monitored with the combined suite of aerosol instrumentation. Results from the intercomparison study not only calibrated the different instruments used in the study, but also provided critical details about how atmospheric processing influences the radiative effects of primary combustion particles<br>Thesis (PhD) — Boston College, 2008<br>Submitted to: Boston College. Graduate School of Arts and Sciences<br>Discipline: Chemistry
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4

Lim, Tongli. "Fabrication of high energy density tin/carbon anode using reduction expansion synthesis and aerosol through plasma techniques." Thesis, Monterey, California: Naval Postgraduate School, 2017. http://hdl.handle.net/10945/53011.

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Approved for public release; distribution is unlimited<br>The aim of this study was to fabricate tin/carbon (Sn/C) battery anodes using a novel approach, reduction expansion synthesis (RES), and test their performance as electrodes in lithium or sodium batteries. A second preparation route, the Aerosol-Through-Plasma (ATP) method, was also employed for comparison. The specimens generated were characterized, before and after cycling, using techniques such as X-ray diffraction, scanning, and transmission electron microscopy. The RES technique was successful in creating remarkably small (ca. <5 nm) nano-scale particles of tin dispersed on the carbon support. The use of the electrodes as part of coin cell batteries resulted in capacitance values of 320 mAh/g and 110 mAh/g for lithium-ion and sodium-ion batteries, respectively. Nano-sized Sn particles were found before and after cycling. It is believed that bonds between metal atoms and dangling carbon produced via the reduction of the carbon surface during RES were responsible for the materials' ability to withstand stresses during lithiation, avoid volumetric expansion, and prevent disintegration after hundreds of cycles. When tin loading in Sn/C was increased from 10% to 20%, an increase of capacitance from 280 mAh/g to 320mAh/g was observed; thus, increased tin loading is recommended for future studies. Tin/carbon produced using ATP presented morphology consistent with stable electrodes, although battery testing was not completed because of the difficulty of producing the material in sufficient quantity.<br>Military Expert 5, Republic of Singapore Navy
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5

Johnson, Graham Richard. "The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16117/1/Graham_Johnson_Thesis.pdf.

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Marine aerosols have attracted increasing attention over the past 15 years because of their potential significance for global climate modelling. The size distribution of these aerosols extends from super-micrometer sea salt mode particles down through 150 nm accumulation mode particles, 40 nm Aitken mode particles and nucleation mode particles which extend from 25 nm right down to clusters of a few molecules. The process by which the submicrometer modes form and grow and their composition have remained topics of debate throughout this time in large part because of the difficulties associated with determining their composition and relating it to proposed models of the formation process. The work compared the modality of marine aerosol influencing the South-east-Queensland region with that of other environmental aerosols in the region. The aerosol was found to be consistent with marine aerosols observed elsewhere with concentrations below 1000 cm-3 and frequently exhibiting the distinct bimodal structure associated with cloud processing, consisting of an Aitken mode at approximately 40 nm, an accumulation mode in the range 100-200 nm and a coarse mode attributed to sea salt between 600 and 1200 nm. This work included the development of two new techniques for aerosol research. The first technique measures aerosol density using a combination of aerosol size distribution and gravimetric mass concentration measurements. This technique was used to measure the density of a number of submicrometer aerosols including laboratory generated NaCl aerosol and ambient aerosol. The densities for the laboratory generated aerosols were found to be similar to those for the bulk materials used to produce them. The technique, extended to super-micrometer particle size range may find application in ambient aerosol research where it could be used to discriminate between periods when the aerosol is dominated by NaCl and periods when the density is more representative of crustal material or sulfates. The technique may also prove useful in laboratory or industrial settings for investigating particle density or in case where the composition is known, morphology and porosity. The second technique developed, integrates the existing physicochemical techniques of volatilisation and hygroscopic growth analysis to investigate particle composition in terms of both the volatilisation temperatures of the chemical constituents and their contribution to particle hygroscopic behaviour. The resulting volatilisation and humidification tandem differential mobility analyser or VH-TDMA, has proven to be a valuable research tool which is being used in ongoing research. Findings of investigations relating the composition of the submicrometer marine aerosol modes to candidate models for their formation are presented. Sea salt was not found in the numerically dominant particle type in coastal nucleation mode or marine Aitken and accumulation modes examined on the Southeast Queensland coast during periods where back trajectories indicated marine origin. The work suggests that all three submicrometer modes contain the same four volatile chemical species and an insoluble non-volatile residue. The volatility and hygroscopic behaviours of the particles are consistent with a composition consisting of a core composed of sulfuric acid, ammonium sulfate and an iodine oxide coated with a volatile organic compound. The volume fraction of the sulfuric acid like species in the particles shows a strong dependence on particle size.
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6

Johnson, Graham Richard. "The Formation and Growth of Marine Aerosols and the Development of New Techniques for their In-situ Analysis." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16117/.

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Marine aerosols have attracted increasing attention over the past 15 years because of their potential significance for global climate modelling. The size distribution of these aerosols extends from super-micrometer sea salt mode particles down through 150 nm accumulation mode particles, 40 nm Aitken mode particles and nucleation mode particles which extend from 25 nm right down to clusters of a few molecules. The process by which the submicrometer modes form and grow and their composition have remained topics of debate throughout this time in large part because of the difficulties associated with determining their composition and relating it to proposed models of the formation process. The work compared the modality of marine aerosol influencing the South-east-Queensland region with that of other environmental aerosols in the region. The aerosol was found to be consistent with marine aerosols observed elsewhere with concentrations below 1000 cm-3 and frequently exhibiting the distinct bimodal structure associated with cloud processing, consisting of an Aitken mode at approximately 40 nm, an accumulation mode in the range 100-200 nm and a coarse mode attributed to sea salt between 600 and 1200 nm. This work included the development of two new techniques for aerosol research. The first technique measures aerosol density using a combination of aerosol size distribution and gravimetric mass concentration measurements. This technique was used to measure the density of a number of submicrometer aerosols including laboratory generated NaCl aerosol and ambient aerosol. The densities for the laboratory generated aerosols were found to be similar to those for the bulk materials used to produce them. The technique, extended to super-micrometer particle size range may find application in ambient aerosol research where it could be used to discriminate between periods when the aerosol is dominated by NaCl and periods when the density is more representative of crustal material or sulfates. The technique may also prove useful in laboratory or industrial settings for investigating particle density or in case where the composition is known, morphology and porosity. The second technique developed, integrates the existing physicochemical techniques of volatilisation and hygroscopic growth analysis to investigate particle composition in terms of both the volatilisation temperatures of the chemical constituents and their contribution to particle hygroscopic behaviour. The resulting volatilisation and humidification tandem differential mobility analyser or VH-TDMA, has proven to be a valuable research tool which is being used in ongoing research. Findings of investigations relating the composition of the submicrometer marine aerosol modes to candidate models for their formation are presented. Sea salt was not found in the numerically dominant particle type in coastal nucleation mode or marine Aitken and accumulation modes examined on the Southeast Queensland coast during periods where back trajectories indicated marine origin. The work suggests that all three submicrometer modes contain the same four volatile chemical species and an insoluble non-volatile residue. The volatility and hygroscopic behaviours of the particles are consistent with a composition consisting of a core composed of sulfuric acid, ammonium sulfate and an iodine oxide coated with a volatile organic compound. The volume fraction of the sulfuric acid like species in the particles shows a strong dependence on particle size.
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7

Gawryla, Matthew Daniel. "Low Density Materials through Freeze-Drying:Clay Aerogels and Beyond…" Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1247013426.

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8

Lau, Bobby Wing Shun. "A complete model of the infrared dielectric function of a low-density silica aerogel /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.

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9

Ekström, Alexander, Olof Gustafsson, Anders Kvarned, et al. "Mechanical properties dependence on microstructure in aerogel-like Quartzene®." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226525.

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In this project the relation between pore size/porosity and the mechanical properties has been studied in the aerogel-like material Quartzene®. Quartzene® is a patented material produced by Svenska Aerogel AB. Density measurements were made on three different types of Svenska Aerogels ABs Quartzene® in the shape of pellets.These three types of Quartzene® is called CMS, ND and E9. The mechanical properties were studied by doing diametrical crush-tests on the pellets. Afterwards the samples were examined through SEM in order to study the structural properties like porosity and microstructure. By examining the materials in this order the group hoped to find a correlation between the mechanical properties and the pore size/porosity. Other microscopic analyses such as TEM and FIB was considered, but due to time limitation these methods were not used. Rough density measurements resulted in an estimated density of 0.82-0.88 g/cm3 for CMS, 0.28-0.30 g/cm3 for E9 and 0.21-0.22 g/cm3 for ND. The crush-tests resulted in a mean fracture stress of 0.81-0.89 MPa for CMS, 0.30 MPa for E9 and 0.20-0.21 MPa for ND. Studying the materials in SEM resulted in an observed mean pore size of 59-73 nm for CMS, 264-362 nm for E9 and 690-710 nm for ND in the mesoporous domain. A subtle relationship between density/pore size and fracture was obtained, with a higher density and smaller pores leading to a higher fracture stress. Due to the lack of data in this study, it is recommended though that this is something that should be examined further before any conclusions can be made. In general Quartzene® has shown to be a brittle material, but this study indicates that the mechanical properties could be controlled in somehow through the microstructure of the material, focusing on controlling the pore sizes. Further investigations in sintering of Quartzene® are also recommended in this study because of its promising effects on the mechanical properties shown in other studies.
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Jadon, Ankita. "Interactions between sodium carbonate aerosols and iodine fission-products." Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R021/document.

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L’analyse de sûreté des réacteurs à neutrons rapides refroidis au sodium de Génération IV nécessite l'étude des conséquences d'un accident grave en cas de rejet dans l'environnement du sodium et des radionucléides qu'il transporte (terme source chimique et radiologique). Le terme source global dépend donc à la fois de la spéciation chimique des aérosols de sodium, issus de la combustion du sodium dans l'enceinte, et de leurs interactions avec les radionucléides. Au cours de cette thèse, les interactions entre le carbonate de sodium et les produits de fission gazeux iodés (I2 et HI) ont été étudiées aux échelles atomique et macroscopique, via une double approche théorique et expérimentale. Une expression analytique de l'isotherme d'adsorption a été développée. La stabilité relative des surfaces du carbonate de sodium a été déterminée par des calculs ab initio utilisant la théorie de la densité fonctionnelle. La réactivité de l'iode a été étudiée pour les surfaces les plus stables et les isothermes d'adsorption évaluées. En parallèle, la cinétique de capture de l'iode moléculaire par le carbonate de sodium a été déterminée expérimentalement pour différentes conditions. L'ensemble des résultats montrent une capture efficace de l'iode moléculaire par le carbonate de sodium à 373 K, variant selon la pression partielle d'iode et la surface du carbonate. Pour les conditions représentatives d'un accident grave, les sites d'adsorption de la surface de carbonate de sodium la plus favorable seront majoritairement vides ou doublement occupés selon la pression partielle d'iode moléculaire, conduisant à une pression d'équilibre inférieure à 2x10-4 bar à 373 K<br>The safety analysis of Generation IV sodium-cooled fast neutron reactors requires the study of the consequences of a severe accident in case of release into the environment of sodium and the radionuclides it carries (term chemical and radiological source). The global source term therefore depends on both the chemical speciation of sodium aerosols, resulting from the combustion of sodium in the containment, and their interactions with radionuclides. During this thesis, the interactions between sodium carbonate and iodinated gaseous fission products (I2 and HI) were studied at the atomic and macroscopic scales, via a combined theoretical and experimental approach. An analytical expression of the adsorption isotherm has been developed. The relative stability of the sodium carbonate surfaces was determined by ab initio calculations using density functional theory. The reactivity of iodine has been studied for the most stable surfaces and the adsorption isotherms evaluated. In parallel, the kinetics of capture of molecular iodine by sodium carbonate has been determined experimentally for different boundary conditions.The results show an effective capture of the molecular iodine by sodium carbonate at 373 K, varying according to the partial pressure of iodine and the surface of the carbonate sorbent. For the representative conditions of a severe accident, the adsorption sites of the most favorable sodium carbonate surfaces will be mostly bare or doubly occupied depending on the partial pressure of molecular iodine; leading to an equilibrium pressure of less than 2x10-4 bar at 373 K
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11

Bamford, Erik, Gustav Ek, Daniel Hedbom, et al. "Quartzene – A promising thermal insulator : Studies of thermal conductivity’s dependence of density and compression of Quartzene® in the form of powder." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-228087.

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The purpose of this project was to study Svenska Aerogel AB’s product Quartzene®, and develop its capacity as a thermal insulator. Quartzene® is a silica based mesoporous material developed by Svenska Aerogel AB, with properties similar to aerogels produced by the sol-gel process. In this report, the correlation between pore structure and thermal conductivity in the material has been studied using techniques, such as scanning electron microscopy, focused ion beam, finite element simulations and transient plane source. Its properties are interesting because of the expanding market of insulated vacuum panels; in which Svenska Aerogel AB wish to expand to. It was found that the pore sizes of M21-BU increased after compression, and the pore sizes of M4-0-2 decreased. The pore sizes of M21-BU became so large that the Knudsen effect is no longer of interest, and that could explain the different behaviors in thermal conductivity.
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12

Bouaniche, Alexandre. "A hybrid stochastic-sectional method for the simulation of soot particle size distributions Vitiated high karlovitz n-decane/air turbulent flames: scaling laws and micro-mixing modeling analysis A hybrid stochastic/fixed-sectional method for solving the population balance equation." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMIR23.

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Les particules de suie (qui sont un type de particules ultrafines) peuvent être produites et émises dans des conditions de combustion riche. Les secteurs comme les transports (routier et aérien), où l'industrie sont des contributeurs significatifs aux émissions de particules. Celles-ci sont habituellement considérées comme des polluants dans la mesure où leur impact négatif sur la santé a été mesuré. Dans certains cas spécifiques comme la production de nanomatériaux, elles peuvent être synthétisées de manière volontaire. Dans les deux cas, une compréhension précise et une capabilité de prédiction de la distribution de tailles de particules (PSD en anglais) sont nécessaires, pour une meilleure conception des chambres de combustion. Dans cette thèse, une méthode innovante est proposée pour la prédiction de l'évolution de la distribution de tailles de particules (PSD). Elle consiste en une approche hybride composée de particules stochastiques représentant une fonction de densité de probabilité (PDF en anglais) et de sections fixes. L'objectif est de résoudre de manière précise le terme source de croissance/oxydation, en traitant le problème de diffusion numérique rencontré par des méthodes sectionnelles classiques. D'autre part, la méthode proposée est moins coûteuse qu'une méthode de Monte Carlo complète. D'abord, le contexte et les motivations de cette thèse sont expliqués. Les concepts et modèles pour les termes sources physiques de suie sont brièvement résumés. Ensuite, l'équation de bilan de population (PBE en anglais) qui pilote l'évolution de la distribution de tailles de particules (PSD), est présentée, ainsi que les différentes classes de méthodes utilisées pour sa résolution. La nouvelle méthode hybride est introduite. Sa précision et son efficacité sont démontrées sur des cas tests analytiques. Enfin, la méthode est appliquée sur une flamme prémélangée d'éthylène<br>Soot particles (which are one kind of ultra-fine particles) can be produced and emitted in fuel rich combustion conditions. Sectors like road and air transportation, or industry are significant contributors to soot particles emissions. Soot particles are usually considered as a pollutant as their negative impact on health has been assessed. In some specific cases like nanomaterials production, they can be synthesized on purpose. In both cases, accurate understanding and prediction capability of the Particle Size Distribution (PSD) is needed, for a better combustors design. In this thesis, a novel numerical method is proposed to predict the Particle Size Distribution (PSD) evolution. It consists in a hybrid approach featuring stochastic particles representing a Probability Density Function (PDF), and fixed sections. The objective is to solve accurately for the surface growth/oxidation term, mitigating the problem of numerical diffusion encountered in some classical sectional methods. On the other hand, the proposed method is less expensive than a full Monte Carlo method. First, the context and motivation of the thesis are explained. Concepts and models for soot physical source terms are shortly reviewed. Then, the Population Balance Equation (PBE), which drives the evolution of the Particle Size Distribution (PSD), is presented as well as the different classes of numerical methods used for its resolution. Subsequently, the novel hybrid method is introduced. Its accuracy and efficiency are demonstrated on analytical test cases. Finally, the method is applied on a premixed ethylene sooting flame
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Groult, Sophie. "Les aérogels de pectine : matériaux avancés pour l'isolation thermique et la libération de médicaments." Thesis, Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEM016/document.

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Les aérogels sont des matériaux nano-structurés ultralégers, hautement poreux et présentant une surface spécifique élevée. Les bio-aérogels sont une nouvelle génération d'aérogels entièrement bio-sourcés, offrant de ce fait de grands potentiels pour des applications à l’interface avec le vivant tout en valorisant la biomasse. Dans le cadre de cette thèse, la pectine a été utilisée pour produire des bio-aérogels. Deux principaux objectifs ont été atteints : • Le premier était de déterminer et de maîtriser les corrélations existantes entre les caractéristiques de la pectine et les conditions de préparation d’une part, avec la structure interne de l'aérogel et ses propriétés physico-chimiques d’autre part. • Le second était d’évaluer et développer les aérogels de pectine pour deux applications distinctes : l'isolation thermique et la libération de médicaments. Il a été établi que les différents mécanismes de formation du réseau, la gélification et la séparation de phase, jouaient un rôle majeur sur la morphologie et les propriétés finales de l'aérogel. La conductivité thermique des aérogels de pectine s'est révélée très faible, de l'ordre de 0,015 à 0,020 W/(m.K), et a présenté une courbe de dépendance en forme de U avec leurs densités. Les aérogels ont également été utilisés en tant que matrices supports de médicament. Les cinétiques de libération du médicament en milieu liquide ont été corrélées aux structures et densités des aérogels de pectine. Des aérogels composites, de type cellulose-pectine et silice-pectine, ont été préparés et utilisés comme supports de médicament menant à une libération prolongée du principe actif dans le temps. Dans cette thèse, nous avons mis en évidence le potentiel élevé des aérogels de pectine utilisés en tant que biomatériaux avancés, versatiles et aux fonctionnalités ajustables<br>Aerogels are ultra-light, highly porous and nano-structured materials with high specific surface area. Bio-aerogels are a new generation of aerogels that are fully biomass-based, which opens up a lot of potentials in biomass valorization and life science applications. In this work pectin was used to produce bio- aerogels. Two main objectives were achieved : • The first was to understand and correlate the characteristics of pectin and the preparation conditions with the internal structure of aerogel and its physico-chemical properties. • The second was to evaluate and develop pectin aerogels as advanced bio-materials for the two different applications : thermal insulation and drug delivery. Various mechanisms of network formation, gelation and non-solvent induced phase separation, were demonstrated to play a very important role in aerogel morphology and properties. Thermal conductivity of pectin aerogels was very low, around 0.015 - 0.020 W/(m.K), and showing U-shape dependence on density. When used as drug delivery matrices, the kinetics of drug release was correlated with pectin aerogels’ structure and density. Composite cellulose-pectin and silica-pectin aerogels were synthesized and also used as drug carriers; a prolonged release was recorded. A high potential of pectin aerogels to be used as versatile bio-materials with advanced tunable functionalities was demonstrated
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14

Hiron, Thibault. "Experimental and modeling study of heterogeneous ice nucleation on mineral aerosol particles and its impact on a convective cloud." Thesis, Université Clermont Auvergne‎ (2017-2020), 2017. http://www.theses.fr/2017CLFAC074/document.

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L’un des enjeux principaux dans l’appréhension de l’évolution du climat planétaire réside dans la compréhension du rôle des processus de formation de la glace ainsi que leur rôle dans la formation et l’évolution des nuages troposphériques. Un cold stage nouvellement construit permet l’observation simultanée de jusqu’à 200 gouttes monodispersées de suspensions contenant des particules de K–feldspath, connues comme étant des particules glaçogènes très actives. Les propriétés glaçogènes des particules résiduelles de chaque goutte sont ensuite comparées pour les différents modes de glaciation et le lien entre noyau glaçogène en immersion et en déposition est étudié. Les premiers résultats ont montré que les mêmes sites actifs étaient impliqué dans la glaciation par immersion et par déposition. Les implications atmosphériques des résultats expérimentaux sont discutés à l’aide de Descam (Flossmann et al., 1985), un modèle 1.5–d à microphysique détaillée dans une étude de cas visant à rendre compte du rôle des différents mécanismes de glaciation dans l’évolution dynamique du nuage convective CCOPE (Dye et al., 1986). Quatre types d’aérosol minéraux (K–feldspath, kaolinite, illite et quartz) sont utilisés pour la glaciation en immersion, par contact et par déposition, à l’aide de paramétrisations sur la densité de sites glaçogènes actifs. Des études de sensibilité, où les différents types d’aérosols et modes de glaciation sont considérés séparément et en compétition, permettent de rendre compte de leurs importances relatives. La glaciation en immersion sur les particules de K–feldspath s’est révélée comme ayant le plus d’impact sur l’évolution dynamique et sur les précipications pour un nuage convectif<br>One of the main challenges in understanding the evolution of Earth's climate resides in the understanding the ice formation processes and their role in the formation of tropospheric clouds as well as their evolution. A newly built humidity-controlled cold stage allows the simultaneous observation of up to 200 monodispersed droplets of suspensions containing K-feldspar particles, known to be very active ice nucleating particles. The ice nucleation efficiencies of the individual residual particles were compared for the different freezing modes and the relationship between immersion ice nuclei and deposition ice nuclei were investigated. The results showed that the same ice active sites are responsible for nucleation of ice in immersion and deposition modes.The atmospheric implications of the experimental results are discussed, using Descam (Flossmann et al., 1985), a 1.5-d bin-resolved microphysics model in a case study aiming to assess the role of the different ice nucleation pathways in the dynamical evolution of the CCOPE convective cloud (Dye et al., 1986). Four mineral aerosol types (K-feldspar, kaolinite, illite and quartz) were considered for immersion and contact freezing and deposition nucleation, with explicit Ice Nucleation Active Site density parameterizations.In sensitivity studies, the different aerosol types and nucleation modes were treated seperately and in competition to assess their relative importance. Immersion freezing on K-feldspar was found to have the most pronounced impact on the dynamical evolution and precipitation for a convective cloud
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15

Gabay, Claude. "Transitions de phases de l'hélium dans les aérogels de silice." Université Joseph Fourier (Grenoble), 2001. http://www.theses.fr/2001GRE10067.

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Ce travail experimental est une contribution a l'etude de deux phenomenes critiques de l'helium dans les aerogels de silice. Dans le but de detecter d'eventuels changements de classe d'universalite du point critique liquide-gaz pour l'helium adsorbe dans les aergels, nous avons developpe un capteur de densite original constitue d'un pendule simple dont la masse est celle de l'aerogel et de l'helium qu'il contient. Ce dispositif a ete valide en etudiant, pour sept echantillons differents, l'apparition de la superfluidite de l'helium. Des resultats connus ont ete ainsi reproduits, et nous apportons des informations complementaires sur le lien entre la dimension fractale des aerogels et l'exposant critique de la densite superfluide. Ce pendule a ensuite permis l'etude de la condensation de l'helium dans les aerogels, a proximite du point critique liquide-gaz. Nos resultats sont largement contradictoires avec ceux reportes dans la litterature sur ce meme systeme : d'apres nos mesures, a la pression de saturation de l'helium libre, le remplissage en liquide est incomplet. Aucune transition bien definie du premier ordre ne semble presente a des pressions inferieures a la pression de condensation de l'helium libre. Il existe cependant une region ou la densite de l'helium varie tres rapidement avec la pression. Ces resultats ressemblent en partie a ceux obtenus dans des materiaux poreux plus traditionnels que les aerogels, ou ils sont interpretes en terme de condensation capillaire. Enfin, des constantes de temps extremement grandes sont observees dans la region de condensation capillaire. Ce type de ralentissement est attendu theoriquement, et il serait du ici au mouvement d'une interface (2d) dans un milieu desordonne.
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16

Félix, Vincent. "Caractérisation thermique de matériaux isolants légers. Application à des aérogels de faible poids moléculaire." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL095N/document.

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La problématique de la sauvegarde de l’énergie pose un certain nombre de défis à la science, en particulier celui de son efficacité. La conception et la caractérisation de nouveaux matériaux isolants thermiques plus performants se révèlent donc fondamentales dans cette perspective. Les aérogels se présentent comme de sérieux candidats dans ce domaine, leur procédé de fabrication confère à certains d’entre eux des caractéristiques extrêmes telles qu’une grande porosité et une faible masse volumique. La caractérisation thermique de tels matériaux est délicate, leur faible sensibilité aux flux thermiques qui les traversent rend les méthodes connues difficiles à mettre en œuvre. A travers l’étude d’échantillons d’aérogels de faible poids moléculaire conçus au LCPM, une méthode de caractérisation adaptée a été développée. Cette méthode de type « tri-couche » offre les avantages d’être robuste et de s’affranchir de la connaissance de paramètres difficiles à atteindre dans de tels cas. La description et la validation de cette méthode sont l’objet principal de ce travail. Par ailleurs, les mesures de conductivité thermique sous vide ont été exploitées et ont permis une compréhension plus poussée de la structure de ces aérogels. Les résultats obtenus dans cette étude ouvrent donc des perspectives en vue de l’optimisation de nouvelles solutions pour l’isolation thermique<br>The issue of preserving energy raises a number of challenges to science, particularly its efficiency. The conception and characterization of new more efficient thermal insulating materials prove fundamental in this regard. Aerogels appear as serious candidates in this area, their manufacturing process provides extreme characteristics such as high porosity and low density for some of them. Thermal characterization of such materials is tricky, their low sensitivity to heat flux makes well-known methods difficult to implement. Through the study of low molecular weight aerogel samples designed by the LCPM a characterization method suitable to these samples has been developed by the LEMTA. This “three-layers” method offers the advantages of being robust and to overcome the knowledge of parameters that are difficult to reach in such cases. Describing and validating this method is the main object of this work. In addition, thermal conductivity measurements under vacuum have been processed which allowed a deeper understanding of the structure of aerogels. The results obtained this study open perspectives for the optimization of new solutions for thermal insulation
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17

Κωστενίδου, Ευαγγελία. "Usage of aerosol mass spectrometry for the measurement of the physical and chemical properties of the atmospheric nanoparticles." Thesis, 2010. http://nemertes.lis.upatras.gr/jspui/handle/10889/3343.

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The Aerosol Mass Spectroscopy (AMS) is a recently developed method that provides on-line measurements of the chemical composition, mass spectrum and mass distributions of the atmospheric aerosol. Using the AMS with a thermodenuder in smog chamber experiments of ozonolysis of α-pinene, β-pinene and limonene, the mass spectrum of the secondary organic aerosols (SOA) is deconvoluted in low, medium and high volatility mass spectra. The spectrum of the surrogate component with the lower volatility for α-pinene and β-pinene is quite similar to that of ambient oxygenated organic aerosol (OOA). This could explain part of the difference between the AMS mass spectrum in the lab and the field. Combining an AMS and a Scanning Mobility Particle Sizer (SMPS) in smog chamber experiments of α-pinene, β-pinene and limonene ozonolysis, the density of the SOA is calculated and estimated between 1.4 and 1.65 g cm-3. This high density implies that the SOA is likely in a solid or a waxy state. The method is applied on field measurements at Finokalia, Crete during the FAME. For the summer campaign (FAME-08) the organic density is in the range of 0.8 and 1.8 g cm-3 with a mean value of 1.35±0.22 g cm-3¬, while for the winter (FAME-09) the average organic density is 1.14±0.36 g cm-3. This technique can also calculate the Collection Efficiency (CE) of the AMS, since AMS does not measure all the particles that enter the instrument. Applying the estimated CE, the AMS is in a good agreement with other instrumentation. The CE and the organic density of the thermodenuded samples are calculated as well. The CE and the organic density both for the ambient and the themodenuded samples are used as post corrections in the volatility estimation. For FAME-08 the organic aerosol is one order of magnitude less volatile than laboratory-generated α-pinene SOA. Furthermore they are highly oxidized due to the photochemistry conditions (especially in the summer) and the station location (away from detectable sources of pollution). Finally, modifying the steam-jet aerosol collector (SJAC) method both particulate and gas phase of the main inorganic species can be measured. Testing the approach at ambient conditions at the ICE-FORTH Institute, we were able to measure together with the inorganic aerosol composition the gas-phase concentrations of NH3, HONO and very low HNO¬3. The results are consistent with the predictions of the thermodynamic model ISORROPIA.<br>Τα αεροζόλ είναι σωματίδια που αιωρούνται στην ατμόσφαιρα. Η Φασματομετρία Μάζας Αεροζόλ (AMS) είναι μία νέα μέθοδος που μπορεί να δώσει ταυτόχρονα και σε πραγματικό χρόνο τη χημική σύσταση, το φάσμα μάζας και τις κατανομές μάζας των ατμοσφαιρικών σωματιδίων. Χρησιμοποιώντας το AMS με έναν θερμικό απογυμνωτή σε πειράματα οζονόλυσης α-πινενίου, β-πινενίου και λεμονενίου σε περιβαλλοντικό θάλαμο, το φάσμα μάζας των δευτερογενών οργανικών σωματιδίων (SOΑ) αναλύεται σε 3 επιμέρους φάσματα, ανάλογα με την πτητικότητα των οργανικών σωματιδίων. Το φάσμα που αντιστοιχεί στις ενώσεις με τη χαμηλότερη πτητικότητα για το α- και β-πινένιο είναι αρκετά όμοιο με αυτό των οξυγονωμένων οργανικών σωματιδίων (ΟΟΑ) από το περιβάλλον. Αυτό εξηγεί και μέρος της διαφοράς του φάσματος μάζας AMS μεταξύ εργαστηρίου και πεδίου. Συνδυάζοντας το AMS με ένα σαρωτή μεγέθους κινούμενων σωματιδίων (SMPS) υπολογίζεται η πυκνότητα των SOA από οζονόλυση α-πινενίου, β-πινενίου και λεμονενίου μεταξύ 1.4 και 1.65 g cm-3. Η σχετικά υψηλή τιμή της πυκνότητας μάλλον σημαίνει ότι τα παραγόμενα σωματίδια είναι στερεά ή κερώδη.Η παραπάνω μέθοδος εφαρμόζεται σε μετρήσεις πεδίου στη Φινοκαλιά, στην Κρήτη (FAME). Για το FAME-08 (καλοκαίρι) η πυκνότητα των οργανικών σωματιδίων είναι μεταξύ 0.8 και 1.8 g cm-3 με μέση τιμή 1.35±0.22 g cm-3, ενώ για το FAME-09 (χειμώνας) η μέση τιμή είναι 1.14±0.36 g cm-3. Η τεχνική αυτή υπολογίζει και το ποσοστό συλλογής (CE) σωματιδίων του AMS, καθώς το AMS μετράει ένα ποσοστό αυτών. Εφαρμόζοντας την CE που υπολογίζεται, η συμφωνία μεταξύ του AMS και άλλων οργάνων είναι αρκετά καλή. Υπολογίζεται επίσης η CE και η πυκνότητα των οργανικών για τα δείγματα που έχουν θερμανθεί στον θερμικό απογυμνωτή. Οι CE και οι οργανικές πυκνότητες χρησιμοποιούνται ως διορθώσεις για την αποφυγή υποεκτίμησης της πτητικότητας του οργανικού αεροζόλ. Για το FAME-08 οι οργανικές ενώσεις είναι περισσότερο από μία τάξη μεγέθους λιγότερο πτητικές από τα SOA που δημιουργούνται σε συνθήκες εργαστηρίου. Επίσης είναι υψηλά οξειδωμένες λόγω της φωτοχημείας (καλοκαίρι) και της τοποθεσίας της δειγματοληψίας (μακριά από πρωτογενείς ρύπους). Τέλος τροποποιώντας τη μέθοδο δειγματοληψίας υγροποιημένων σωματιδίων (SJAC) είναι δυνατό να μετρηθεί και η σωματιδιακή αλλά και η αέρια φάση των κυρίως ανόργανων ενώσεων. Πειράματα που έγιναν από δειγματοληψία στο ΕΙΧΗΜΥΘ δείχνουν την ύπαρξη ΝΗ3 αλλά σχεδόν μηδενικού ΗΝΟ3. Τα αποτελέσματα συγκρίνονται με ένα θερμοδυναμικό μοντέλο (ISΟRROPIA) και η συμφωνία είναι καλή.
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18

Πικριδάς, Μιχαήλ. "Characterization and sources of atmospheric particles in different population density environments." Thesis, 2012. http://hdl.handle.net/10889/6474.

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In order to reduce uncertainty of atmospheric particle emissions and to examine the mechanism of new particle formation from precursor gases, measurements were conducted in a megacity (Paris, France), an urban area (Patras, Greece) and a remote location (Finokalia, Greece). At Finokalia, the composition of particles with diameter smaller than 1 μm (PM1) depended on air mass origin. The highest concentrations, and most frequent, were observed when air masses were coming from Europe. Organic aerosol was found to be 80% water soluble and the increased organic to elemental carbon ratio correlated with ozone concentration. These findings indicate that particulate matter (PM) at Finokalia was not emitted near the site but was transported from source regions hunderd of kilometers away and thus the area can be considered as a background of Europe. At Finokalia, atmospheric nucleation was observed more frequently during winter when sunlight intensity was below average and favored by air masses that crossed land before reaching the site. This behavior was explained by ammonia involvement in the nucleation process. PM1 was mainly acidic during summer and consumed all available ammonia, contrary to winter when, due to the lower sunlight intensity, particles were neutral and ammonia was available. During both seasons nucleation would only occur if particles were neutral which resulted in higher frequency of events during winter. Air masses that crossed land before reaching the site were enriched with ammonia, thus it was more likely for nucleation to occur. Number size distributions were monitored in Paris, France at fixed and mobile ground stations along with airborne measurements. The Paris plume was identified at a distance of at least 200 km from the city center and the number concentration was found to increase even by a 3-fold when air masses crossed Paris. During summer nucleation was observed approximately half of the campaign days; when the condensational sink was lower than average contrary to winter when no event was identified due to higher sink. Increased number concentration was observed at an altitude outside of the Paris plume simultaneously with new particle formation observed on the ground and was attributed to that phenomenon. At Patras, the legislated by E.U. daily PM10 standards were found to be violated. Exceedances were more frequent (58 of a total of 75) during the colder months (October to March) of the year. The warmer months (April to September) 80% of the PM2.5 was transported from other areas. Contrary during the colder months the contribution of transported PM reduced to 70% during autumn and 50% during winter, when the highest concentrations were observed on average. Local traffic contributed approximately 15% during winter and the remaining 35% was primarily due to domestic heating. PM2.5 and PM1 concentrations were found to exceed 100 μg m-3 on several occasions during nighttime due to domestic heating, either diesel or biomass combustion. Potassium, a tracer of biomass combustion, correlated well (R2=0.79) with PM2.5 during winter indicating a biomass source. Potassium concentrations were higher within the urban premises than a rural area located 36 km away from the city, indicating that at least a portion of the biomass combustion related PM2.5 were emitted locally.<br>Με σκοπό την μείωση της αβεβαιότητας των εκπομπών ατμοσφαιρικών σωματιδίων (ΑΣ) καθώς και διευκρίνισης του μηχανισμού σχηματισμού ΑΣ από την οξείδωση πρόδρομων αερίων, μετρήσεις πεδίου έλαβαν χώρα σε μία μεγαλούπολη (Παρίσι, Γαλλία), μία αστική περιοχή (Πάτρα, Ελλάδα) και σε μία απομακρυσμένη τοποθεσία (Φινοκαλιά, Ελλάδα). Στην Φινοκαλιά, η σύσταση των σωματιδίων με διάμετρο μικρότερη από 1 μm (ΑΣ1) εξαρτιόταν από την προέλευση των αερίων μαζών. Τις υψηλότερες συγκεντρώσεις εμφάνιζαν οι αέριες μάζες από τη Ευρώπη, που ήταν και οι πιο συχνές. Οργανικές ενώσεις των ΑΣ, εμφάνιζαν, υψηλή διαλυτότητα στο νερό (80%) και αυξημένο λόγο οργανικού προς στοιχειακό άνθρακα που συσχετιζόταν θετικά με τις συγκεντρώσεις όζοντος. Όλα τα παραπάνω υποδεικνύουν πως τα ΑΣ στην περιοχή της Φινοκαλιάς μεταφέρονταν από γειτονικές περιοχές εκατοντάδες χιλιόμετρα μακριά και συνεπώς η περιοχή μπορεί να θεωρηθεί ως σταθμός υποβάθρου για την Ευρώπη. Στην Φινοκαλιά, το φαινόμενο της ατμοσφαιρικής πυρηνογένεσης ήταν συχνότερο τους χειμερινούς μήνες, όταν η ένταση φωτός ήταν χαμηλότερη, και σε αέριες μάζες που παρέμεναν σημαντικό χρόνο πάνω από την στεριά πριν φτάσουν στον σταθμό. Αυτή η συμπεριφορά εξηγήθηκε με την συμμετοχή της αμμωνίας στην διαδικασία της πυρηνογένεσης. Τα ΑΣ1 το καλοκαίρι ήταν κατά κανόνα όξινα και κατανάλωναν όλη την διαθέσιμη αμμωνία σε αντίθεση με τον χειμώνα, όπου εξαιτίας της χαμηλότερης έντασης φωτός, τα ΑΣ1 ήταν ουδέτερα και υπήρχε διαθέσιμη. Και στις δύο περιόδους η πυρηνογένεση λάμβανε χώρα μόνο όταν τα σωματίδια ήταν ουδέτερα, το οποίο είχε ως αποτέλεσμα υψηλότερη συχνότητα του φαινομένου τους χειμερινούς μήνες. Οι αέριες μάζες όταν παρέμεναν πάνω από στεριά εμπλουτίζονταν με αμμωνία, αυξάνοντας την πιθανότητα πυρηνογένεσης. Κατανομές μεγέθους αριθμού μετρήθηκαν στο Παρίσι, Γαλλίας σε επίγειους σταθμούς, σταθερούς και κινητούς, καθώς και σε υψόμετρο. Ο θύσανος του Παρισιού ταυτοποιήθηκε σε απόσταση τουλάχιστον 200 km από την πόλη και οι συγκεντρώσεις αριθμού ΑΣ αύξαναν ακόμα και κατά 300% όταν οι αέριες μάζες προέρχονταν από το Παρίσι. Το καλοκαίρι πυρηνογένεση έλαβε χώρα τις μισές μέρες της δειγματοληψίας, όταν η διαθέσιμη επιφάνειας συμπύκνωσης ήταν χαμηλή, ενώ το χειμώνα, επειδή η διαθέσιμη επιφάνεια ήταν υψηλότερη, δεν ταυτοποιήθηκε το φαινόμενο. Αυξημένες συγκεντρώσεις αριθμού ΑΣ ταυτοποιήθηκαν εκτός του θυσάνου του Παρισιού ταυτόχρονα με πυρηνογένεση στο έδαφος και αποδόθηκαν σε αυτό το φαινόμενο. Στην Πάτρα τα θεσμοθετημένα από την Ε.Ε. ημερήσια όρια ΑΣ10 βρέθηκαν να παραβιάζονται. Οι υπερβάσεις ήταν πιο συχνές (58 από τις 75) τους ψυχρούς μήνες (Οκτώβριο - Μάρτιο). Τους θερμούς μήνες (Απρίλιο - Σεπτέμβριο) το 80% των ΑΣ2.5 μεταφέρονταν από άλλες περιοχές. Αντίθετα τους ψυχρούς μήνες η συνεισφορά από μεταφερόμενα ΑΣ μειωνόταν στο 70% το φθινόπωρο και 50% το χειμώνα, όταν και οι συγκεντρώσεις ΑΣ2.5 ήταν κατά μέσο όρο οι υψηλότερες στην περιοχή. Η τοπική κυκλοφορία συνείσφερε περίπου 15% τον χειμώνα ενώ ένα σημαντικό κομμάτι από το υπόλοιπο 35% οφειλόταν στην οικιακή θέρμανση. Συγκέντρωση ΑΣ2.5 και ΑΣ1 ίση ή μεγαλύτερη των 100 μg m-3 μετρήθηκε κατ'επανάληψη τις νυχτερινές ώρες των χειμερινών μηνών εξαιτίας της οικιακής θέρμανσης, είτε με πετρέλαιο είτε με καύση βιομάζας Η καύση βιομάζας υποδεικνύεται από την συσχέτιση (R2=0.79) των συγκεντρώσεων ΑΣ2.5 με τις συγκεντρώσεις καλίου, ένα δείκτη καύσης βιομάζας. Οι συγκεντρώσεις αυτού του δείκτη βρέθηκαν υψηλότερες μέσα στον αστικό ιστό από μία αγροτική περιοχή 36 km μακριά από την Πάτρα, αποκλείοντας την αποκλειστική μεταφορά ΑΣ2.5 καύσης βιομάζας από γειτονικές περιοχές.
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19

Grätz, Olga. "Preparation and in-situ Spectroscopic Characterization of High-Energy Density Lithium-Sulphur Batteries." 2019. https://tud.qucosa.de/id/qucosa%3A70984.

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This work was composed of two main parts. In a first step, a electrochemical cell was developed, which could allow the in-situ, in-operando analysis of the functioning battery. The processes taking place inside a running lithium-sulphur cell were then observed and identified with the help of Raman spectroscopy. In a second step, the performance of the cell was studied while using novel cathode materials, as well as modified commercial separators.
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