Dissertations / Theses on the topic 'Ambient atmosphere'
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Abouzreba, Salem Ali. "Volatile fatty acids in the ambient atmosphere." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388115.
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Hennigan, Christopher James. "Properties of secondary organic aerosol in the ambient atmosphere sources, formation, and partitioning /." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26598.
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Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.Committee Chair: Weber, Rodney; Committee Co-Chair: Bergin, Michael; Committee Member: Mulholland, James; Committee Member: Nenes, Athanasios; Committee Member: Russell, Armistead. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Johnson, Bryan Jay. "The carbon isotopic content and concentration of ambient formic and acetic acid." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185355.
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A direct method for source determination of atmospheric formic and acetic acid, through carbon isotopic analysis of the ambient acids and their potential sources, has been successfully developed and tested. These first carbon isotopic measurements of formic acid in the atmosphere were found to be fairly constant, regardless of location. This is consistent with a single dominating source of formic acid, with vegetation emissions being the most likely controlling source. Collection of relatively large quantities (0.3$-$3.0 mg) of the organic acids, which was necessary for carbon isotopic measurements, was effectively accomplished by a new method using calcium hydroxide-treated filters with a high-volume sampler. Samples were collected on a regular basis at Mount Lemmon, Arizona (elevation = 9200 feet A.S.L.). Atmospheric concentrations showed a well-defined seasonal pattern, with the lowest concentrations (about 0.2 ppbv) occurring in the middle of the winter, which steadily increased to a maximum of nearly 2 ppbv in the summer. The ¹³C content (δ ¹³C) of HCOOH averaged -20.9 ± 2.5 ‰ during the growing season (April-September) and -23.2 ± 3.5 ‰ during the non-growing season at Mount Lemmon. Isotopic measurements of formic acid from several other locations included two west coast marine sites (δ ¹³C range of -19.1 to -24.6 ‰), three Colorado Rocky Mountain samples averaging -23.2 ± 1.0 ‰, two from the prairie of North Dakota (-23.5 ± 1.0 ‰) and three samples collected in the urban Tucson, Arizona area (-20.8 ± 3.4 ‰). Source measurements included HCOOH emissions from two species of formicine ants (-18.8 ± 1.7 ‰), and HCOOH in automobile exhaust (-28 ‰ from leaded gasoline, and -48.6 ‰ from unleaded). Further support for a biogenic source of atmospheric HCOOH came from the carbon-14 analysis of six Mount Lemmon HCOOH samples (93-113% modern carbon), using accelerator mass spectrometry. Carbon isotopic fractionation during exchange of HCOOH between the liquid and gas phases was investigated through a gas/liquid partitioning experiment. A first experimental measurement of the Henry's Law coefficient (Kᴴ) averaged 7400 ± 800 M/atm. Fractionation between HCOOH(g) and HCOOH(aq) was found to be negligible.
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Brown, Christopher G. "Laser induced breakdown spectroscopy for detection of organic residues impact of ambient atmosphere and laser parameters." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4860.
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Laser Induced Breakdown Spectroscopy (LIBS) is showing great potential as an atomic analytical technique. With its ability to rapidly analyze all forms of matter, with little-to-no sample preparation, LIBS has many advantages over conventional atomic emission spectroscopy techniques. With the maturation of the technologies that make LIBS possible, there has been a growing movement to implement LIBS in portable analyzers for field applications. In particular, LIBS has long been considered the front-runner in the drive for stand-off detection of trace deposits of explosives. Thus there is a need for a better understanding of the relevant processes that are responsible for the LIBS signature and their relationships to the different system parameters that are helping to improve LIBS as a sensing technology. This study explores the use of LIBS as a method to detect random trace amounts of specific organic materials deposited on organic or non-metallic surfaces. This requirement forces the limitation of single-shot signal analysis. This study is both experimental and theoretical, with a sizeable component addressing data analysis using principal components analysis to reduce the dimensionality of the data, and quadratic discriminant analysis to classify the data. In addition, the alternative approach of 'target factor analysis' was employed to improve detection of organic residues on organic substrates. Finally, a new method of characterizing the laser-induced plasma of organics, which should lead to improved data collection and analysis, is introduced. The comparison between modeled and experimental measurements of plasma temperatures and electronic density is discussed in order to improve the present models of low-temperature laser induced plasmas.ID: 029809549; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 284-297).
Ph.D.
Doctorate
Physics
Sciences
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Sepúlveda, Filipa Maria da Cruz Filipe. "O efeito da musica ambiente no comportamento do consumidor : o caso dos restaurantes." Master's thesis, Instituto Superior de Economia e Gestão, 2011. http://hdl.handle.net/10400.5/10292.
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Mestrado em MarketingO presente estudo visa investigar qual o impacto que a presença de música ambiente e respectivas variações do tempo da música, num ambiente de restaurante, tem junto do comportamento do consumidor, averiguando se é, ou não, uma ferramenta de marketing eficaz. Através de uma abordagem metódica e quantitativa, ir-se-á investigar se a presença de música ambiente e as suas respectivas variações no tempo afectam positivamente o tempo que os consumidores passam no interior do espaço e quais os seus diferentes tipos de gastos. Para isso, foi conduzida uma experiência, num restaurante situado na zona de Miraflores, onde durante 3 semanas se utilizou a técnica de observação para estudar os comportamentos dos consumidores nas 3 condições de estudo: sem música ambiente, com música ambiente de tempo lento e com música ambiente de tempo rápido. Embora os resultados obtidos não permitam validar muitos dos objectivos propostos na presente investigação, verificou-se que muitas das variáveis alvo de estudo, sofreram ligeiras melhorias aquando a presença de música ambiente e em alguns casos mais concretos, aquando da presença de música ambiente com tempo lento.
The following paper aims to explore which is the impact that the presence of environmental music and its respective variations in tempo over a restaurant environment has on consumer behavior, and to check whether or not, it can act as an effective marketing tool. Throughout an exhaustive fact based analysis, it will be investigated if the presence of environmental music, with its variations in tempo, affects positively the time spent inside the restaurant, and which are the impacts over the different spending categories. With that vision in mind, it was conducted an experiment, in a restaurant located on Miraflores, Lisbon area, where during three weeks, the observation method was used to study the consumer behavior on the 3 study conditions: without environmental music, with slow tempo environmental music and finally, with fast tempo environmental music. Although the results obtained did not allowed to validate much of the objectives proposed by the investigation, it was worth of note that plenty of the variables that were studied suffered slight improvements when subjected to environmental music, and in some cases with the use of slow tempo environmental music.
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Mikael, Ali. "Evaluation des paramètres physiques des bâtiments : amortissement, fréquence et modes de comportement des structures de génie civil : approche expérimentale." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00597269.
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La connaissance et la caractérisation du bâti existant est une problématique attirant l'intérêt de nombreuses activités depuis quelques années. L'utilisation des vibrations ambiantes permet de connaître facilement les paramètres dynamiques élastiques de la structure, que sont les fréquences de vibration, les amortissements et les modes de déformations. La fréquence de vibration étant facilement observable par le calcul de la transformée de Fourier d'un enregistrement au sommet de la structure, l'amortissement quant à lui reste un des paramètres les moins bien connus et son origine physique reste imprécise. Dans cette étude, nous essayerons de mesurer la fréquence et l'amortissement sur plusieurs bâtiments, d'évaluer la stabilité et la précision des mesures effectuées, en particulier afin de connaître jusqu'à quelle précision on peut relier des variations des paramètres modaux à des variations des propriétés physiques. Nous analyserons les variations observées pour des périodes variant de 1 mois à plus de 1 an. Ces études continues sur au moins un mois permettront de mettre en évidence les variations réversibles des paramètres dynamiques de la structure, et de les mettre en relation avec des forçages externes. On observe des variations journalières sur la fréquence et l'amortissement dans tous les bâtiments étudiés. La relation entre ces variations, et d'autres variations observées à plus long terme, avec la température diffère d'un bâtiment à l'autre. La relation entre fréquence et amortissement et l'effet de l'Interaction Sol-Structure ont été étudiés.
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Sanderson, Paul. "Measurement and identification of ambient atmospheric metallic nanoparticles." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6426/.
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Physico-chemical characterisation of atmospheric metallic particles collected at six roadside, background and rural sites has been undertaken by multiple methods. Mass-size distributions of total PM mass have been compared between multiple sites and roadside increments calculated in Birmingham, which are found to occur in the size ranges 100-180 nm, 320-560 nm and >1000 nm. Good correlations are observed between Ba, Cu and Fe, but some divergence of sources is evident in small particles. Single-particle analysis by TEM-X-EDS and EELS has classified Fe-dominated particles into two main groups; Fe content >90%/wt and Fe-Mn alloys (Fe ~75%/wt). Both classes are mainly γ-Fe\(_2\)O\(_3\) and α-Fe\(_2\)O\(_3\). Pb-dominated particles have been detected with Zn and Sb. Ce particles have been found as nanoparticles attached to large soot agglomerates. TEM and ICP-MS samples collectedfrom a static brake test rig show changes in mass distributions at different braking forces and between different elements, in particular between Ba, Cu, Fe, Ni and Al. Data from TEM samples of diesel exhaust imply that particles containing Fe, Cr and Ni together may be indicative of this source and that engines are a possible source of submicrometre Cu. Use of Al-alloys in engine design contributes Al-dominated particles to the emitted exhaust.
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Zhang, Ke. "Ambient and plume processing of atmospheric ultrafine particles /." 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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Thomas, Stephen Bradley. "Characterisation of ambient fine and ultrafine atmospheric aerosols." Thesis, Queensland University of Technology, 2001.
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Niania, Mathew. "In-situ analysis of La0.6Sr0.4Co0.2Fe0.8O3-d surface in ambient atmospheres." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/44828.
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The LSCF material system is a desirable material for a Solid Oxide Fuel Cell (SOFC) cathode due to its Mixed Ionic-Electronic Conducting (MIEC) properties. It has been utilised commercially for many years, however, the cell lifetime is inhibited by degradation processes passivating the surface of the electrode. A-site cation segregation is believed to be a primary degradation mechanism due to the formation of electronically insulating secondary phase particles reducing the active surface area that facilitates the oxygen reduction reaction. Numerous reports have studied the overall effect that degradation has on SOFC cell performance, however, it is still unclear the extent to which microstructural changes affect a material's oxygen exchange properties. To date, many studies measuring the oxygen exchange rate utilised pure oxygen atmospheres in order to isolate the effect of oxygen. However, for cost and practicality reasons, the desired gas stream for SOFC is ambient air. Multiple oxygen-containing gaseous components and impurities (such as CO, CO2, H2O, SO2 and NOx) are contained within ambient air and have been shown to alter the oxygen exchange rate or enhance the degradation of MIEC materials. This work focuses upon characterising the effect ambient air has upon the surface microstructure and oxygen exchange rate of the LSCF system. In-situ High-Temperature Environmental Scanning Electron Microscopy (HT-ESEM) was used to analyse the growth rate and growth behaviour of strontium-based particles in pure O2, pure H2O, ambient air and vacuum environments. The HT-ESEM data was directly compared to Electron Backscattered Diffraction crystal orientation data in order to understand what effect the LSCF domain structure had upon the segregation of strontium. It was observed that the surface microstructure has a strong influence on the growth behaviour and growth kinetics of the particles. A common methodology for measuring oxygen self-diffusivity and surface exchange rates is Isotopic Exchange Depth Profiling (IEDP). This traditionally has used pure oxygen as the anneal environment to isolate the exchange properties of the O2 species, however, in the presence of other oxygen containing species the exchange process will be more complicated. In order to analyse the surface exchange rate in ambient air (or any other atmosphere containing a consistent oxygen partial pressure), the novel 'back-exchange' technique was developed. Initial development of the technique has demonstrated its validity and confirmed enhancement of the oxygen exchange rate in ambient air over pure oxygen. Time-of-Flight (ToF) SIMS was used to measure isotopically exchanged diffusion profiles. For materials with a high oxygen self-diffusivity, such as LSCF, the 'line-scan' method must be employed instead of a standard depth profile. The ToF-SIMS utilises a statistical method in order to correct for detector 'dead time', however, this method relies upon the total ion count to remaining constant across each pixel of the raster area. The line-scan method relies upon analysis of a surface perpendicular to the original exchange surface and as such will not have a constant ion count near the sample edge. Errors associated with the measured diffusion profile are discussed and an optimised sample preparation has been proposed.
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Hurley, Roberta Ambrose. "Quantitative Analysis of Acrylon[I]Trile in Ambient Air." W&M ScholarWorks, 1985. https://scholarworks.wm.edu/etd/1539625304.
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Babincová, Kristina. "Pasivace aktivní vrstvy perovskitových solárních článků s invertovanou strukturou." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-444540.
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The topic of this work is the passivation of the active layer of perovskite solar cells with an inverted structure. The work is divided into theoretical and experimental part. The theoretical part describes in particular the passivation and modification of the perovskite layer as well as the characteristic properties of perovskite, including structure and stability. The experimental part deals with the preparation of photovoltaic cells with an inverted structure. For the characterization of photovoltaic cells, reference samples were prepared and their active layer was modified by plasma. The most used deposition technique for the preparation of layers was the spin coating method. From the performed experiments it can be concluded that the preparation of samples and their subsequent modification under laboratory conditions does not lead to the improvement of the final parameters of photovoltaic conversion. By transferring the sample preparation and passivation of the active layer to an inert atmosphere, it was possible to produce cells with higher efficiencies (compared to the reference sample), around 10 %. Another advantage of this plasma treatment of the active layer is that it also improves the stability of the prepared structures, which even after a few days in air show almost 80 % of the original efficiency.
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Yao, Huajian. "Ambient noise interferometry and surface-wave array tomography in southeastern Tibet." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53115.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2009.Includes bibliographical references.
The primary goal of my doctoral research is to understand the crustal and upper mantle structure and deformation in southeastern Tibet. To improve the resolution in the crust, we developed a new approach for surface-wave array tomography by combining inter-station phase velocity dispersion measurements from empirical Green's functions (EGFs) recovered from ambient noise interferometry and from traditional teleseismic surface-wave two-station (TS) analysis. The non-stationarity (e.g., seasonal changes) and non-uniform distribution of ambient noise sources may obstruct full reconstruction of the surface-wave Green's functions, which may, in turn, degrade the accuracy of the tomographic models. Under the assumption of plane-wave propagation, we developed an iterative method to estimate ambient noise energy distribution, phase velocity bias primarily due to uneven noise energy distribution, and azimuthally anisotropic phase velocity maps. With phase velocity dispersion measurements at periods 10 - 150 s from 1 year data of 75 broad band stations in SE Tibet, we performed inversion for wavespeed variations and azimuthal anisotropy. The tomographic images revealed widespread crustal low-velocity zones (LVZs) at middle/lower crustal depth beneath SE Tibet. There is substantial lateral and vertical variability of these zones and some may be truncated by large faults.
(cont.) The pattern of azimuthal anisotropy in the upper crust is consistent with clockwise rotation around the eastern Himalaya syntaxis and a predominance of simple shear and strike-slip faulting in SE Tibet. Comparison of splitting from SKS observations and from our 3D anisotropic model suggests that the contribution to splitting from the crust is at least as important as from the upper mantle in the region west of Sichuan Basin and north of 26°N. However, beneath Yunnan, splitting signal originates mainly from the upper mantle. The radial changes in deformation pattern argue against vertically coherent lithospheric deformation in Tibet. Combined with the widespread crustal LVZs, this supports models of ductile crustal flow beneath SE Tibet. However, the spatial variation in strength and depth of crustal LVZs and in pattern of azimuthal anisotropy suggests that the 3-D geometry of crustal weak layers is complex and that unhindered crustal flow over large regions may not occur.
by Huajian Yao.
Ph.D.
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Samy, Shahryar. "Chemical transformations of complex mixtures relevant to atmospheric processes laboratory and ambient studies /." abstract and full text PDF (UNR users only), 2009. 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:3387822.
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Hagler, Gayle S. W. "Measurement and analysis of ambient atmospheric particulate matter in urban and remote environments." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-05042007-171845/.
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Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2007.Weber, Rodney, Committee Member ; Schauer, James, Committee Member ; Mulholland, James, Committee Member ; Bergin, Mike, Committee Chair ; Russell, Armistead, Committee Member.
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BEURDOUCHE, PASCAL. "Lubrification limite de revetements de ceramiques projetes, en atmosphere ambiante et corrosive." Paris 6, 1989. http://www.theses.fr/1989PA066740.
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L'etude presentee porte sur le comportement de differentes ceramiques en frottement lubrifie. Ces ceramiques sont constituees de melanges d'oxyde de chrome et de carbures de tungstene, projetes au moyen d'une torche a plasma, sur des substrats d'acier et d'aluminium. Le comportement de ces revetements a ete considere en lubrification limite face a eux memes, a un acier nitrure, ou a un nitrure de silicium massif. Les echantillons ont frotte en atmosphere ambiante ou en presence de dioxyde de soufre. Il s'avere que le comportement en frottement et en usure des pieces depend beaucoup de celui des films qui se forment sur celle-ci. Le comportement des films est lie a plusieurs facteurs, a savoir: 1) leur qualite mecanique et leur aptitude a supporter la presence de particules; 2) les conditions de pression et de temperature atteintes dans le contact, qui determinent la vitesse de reaction des lubrifiants; 3) la resistance des materiaux a la fragilisation par fatigue qui determine la presence de particules dans le contact. Parmi les produits essayes, les revetements a base d'oxyde de chrome ont demontre dans ces conditions les meilleures potentialites
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Errajaa, Karim. "L’influence de l’odeur d’ambiance sur le consommateur : le rôle central de la congruence entre l’odeur et l’image de marque." Thesis, Angers, 2018. http://www.theses.fr/2018ANGE0076.
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L'objectif de la présente recherche est de mettre en évidence le rôle central de la congruence entre l'odeur d'ambiance et l'image de marque sur les réactions émotionnelles, cognitives, conatives et la satisfaction du consommateur lors de l'expérience de visite du point de vente. Afin de valider la problématique de recherche, une étude empirique quantitative et expérimentale est conduite in-situ auprès de deux entreprises et en collaboration avec deux cabinets de conseil en marketing olfactif. Dans ce cadre, une double expérimentation est élaborée auprès de deux échantillons de deux enseignes, spécialisées respectivement dans l'offre d'espaces multi-services "coworking, détente, travail..." et l'offre de prêt-à-porter. Les résultats obtenus montrent que la congruence perçue entre l'odeur d'ambiance et l'image de marque peut par exemple exercer dans certains cas une influence positive sur les réactions du consommateur, à savoir les dépenses, la perception de l'atmosphère globale du point de vente, les émotions de plaisir, d'éveil, l'intention de visite. Les résultats mettent en évidence également certains chemins médiateurs et modérateurs de l'influence de la congruence olfactive avec l'image de marque sur les réactions du consommateur. En revanche, la congruence olfactive avec l'image de marque n'a pas d'influence sur certaines réactions du consommateur comme par exemple l'intention d'achat de produits, le temps de visite perçu et réel. Les résultats significatifs et concordants avec les hypothèses initialement formulées confortent l'intérêt pour les praticiens d'investir dans la création des odeurs typiques de leurs images de marque à des fins marketingThe objective of this research is to highlight the central role of the congruence between the odor and the brand image on the emotional, cognitive, behavioral reactions and the satisfaction of the consumer during the experience of visit of the store. In order to validate the research question, a quantitative and experimental study is conducted in-situ at two companies and in collaboration with two olfactory marketing consultants. In this context, a double experiment is developed with two samples of two brands, respectively specialized in the offer of multi-service spaces "coworking, relaxation, work ..." and the ready-to-wear. The results show that the perceived congruence between the odor and the brand image can for example positively influence the consumer's reactions, namely the expenditure, the perception of the global atmosphere of the store, the emotions. The results also highlight some mediating and moderating paths of the influence of olfactory congruence with the brand image on consumer reactions. On the other hand, the olfactory congruence with the brand image has no influence on certain reactions of the consumer such as, for example, the intention to purchase products, the perceived and actual visitation time. Significant results that are consistent with the initial hypotheses reinforce the interest for practitioners to invest in creating the typical smells of their branding for marketing purposes
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Peltier, Richard Edward. "Ambient Submicron Particles In North America: Their Sources, Fate, and Impact." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19750.
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Thesis (Ph.D)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2008.Committee Chair: Weber, Rodney J.; Committee Member: Bergin, Michael H.; Committee Member: Huey, L Gregory; Committee Member: Ingall, Ellery D.; Committee Member: Nenes, Athanasios.
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Huang, Hui Ph D. Massachusetts Institute of Technology. "Ambient noise tomography for wavespeed and anisotropy in the crust of southwestern China." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87518.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references.
The primary objective of this thesis is to improve our understanding of the crustal structure and deformation in the southeastern Tibetan Plateau and adjacent regions using surface wave tomography. Green's functions for Rayleigh and Love waves are extracted from ambient noise interferometry. Using the Green's functions, we first conduct traditional traveltime tomography for the two shear wavespeeds Vsv and Vsh Their differences are measured as radial anisotropy. We then conduct Eikonal tomography to study azimuthal anisotropy in the crust. Our tomography results are well consistent with geology in the study region. In the Sichuan Basin, low wavespeed and positive radial anisotropy (Vsh> Vsv) in the upper crust reflect thick sedimentary layers at surface; high wavespeed and small radial anisotropy in the middle and lower crust reflect a cold and rigid basin root. Little azimuthal anisotropy is observed in the Basin, indicating small internal deformation. In the Tibetan Plateau, we observe widespread low wavespeed zones with positive anisotropy in the middle and lower crust, which may reflect combined effects of weakened rock mechanism and horizontal flow in the deep crust of southeastern Tibet. The northern part of the Central Yunnan block, which geographically coincides with the inner zone of the Emeishan flood basalt, reveals relatively higher wavespeeds than the surrounding regions and little radial anisotropy throughout the entire crust. We speculate that the high wavespeeds and small radial anisotropy are due to combined effects of the remnants of intruded material from mantle with sub-vertical structures and channel flow with sub-horizontal structures. In general, the azimuthal anisotropy in our study region is consistent with a clockwise rotation around the Eastern Himalayan Syntaxis. Careful examination reveals large angular differences between the azimuthal anisotropy in the upper and lower crust, suggesting different deformation patterns at the surface and in depth. Therefore, our tomography results support models with ductile flow in the deep crust of the southeastern Tibetan Plateau; however, the large lateral variation of both wavespeeds and anisotropy indicates that the flow also varies greatly in intensity and pattern in different geological units.
by Hui Huang.
Ph. D.
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Robache, Antoine Guillermo René. "Caractérisation des aérosols dans l'air ambiant application à la recherche de sources /." [S.l.] : [s.n.], 2000. http://www.univ-lille1.fr/bustl-grisemine/pdf/extheses/50376-2000-320-321.pdf.
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Czuba, Eva. "Development of a technique to study stable carbon isotope composition of NMHCs in ambient air." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ56169.pdf.
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Harris, Glenn A. "Fundamentals of ambient metastable-induced chemical ionization mass spectrometry and atmospheric pressure ion mobility spectrometry." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41147.
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Molecular ionization is owed much of its development from the early implementation of electron ionization (EI). Although dramatically increasing the library of compounds discovered, an inherent problem with EI was the low abundance of molecular ions detected due to high fragmentation leading to the difficult task of the correct chemical identification after mass spectrometry (MS). These problems stimulated the research into new ionization methods which sought to "soften" the ionization process. In the late 1980s the advancements of ionization techniques was thought to have reached its pinnacle with both electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI). Both ionization techniques allowed for "soft" ionization of large molecular weight and/or labile compounds for intact characterization by MS. Albeit pervasive, neither ESI nor MALDI can be viewed as "magic bullet" ionization techniques. Both techniques require sample preparation which often included native sample destruction, and operation of these techniques took place in sealed enclosures and often, reduced pressure conditions.
New open-air ionization techniques termed "ambient MS" enable direct analysis of samples of various physical states, sizes and shapes. One particular technique named Direct Analysis In Real Time (DART) has been steadily growing as one of the ambient tools of choice to ionize small molecular weight (< 1000 Da) molecules with a wide range of polarities. Although there is a large list of reported applications using DART as an ionization source, there have not been many studies investigating the fundamental properties of DART desorption and ionization mechanisms.
The work presented in this thesis is aimed to provide in depth findings on the physicochemical phenomena during open-air DART desorption and ionization MS and current application developments. A review of recent ambient plasma-based desorption/ionization techniques for analytical MS is presented in Chapter 1. Chapter 2 presents the first investigations into the atmospheric pressure ion transport phenomena during DART analysis. Chapter 3 provides a comparison on the internal energy deposition processes during DART and pneumatically assisted-ESI. Chapter 4 investigates the complex spatially-dependent sampling sensitivity, dynamic range and ion suppression effects present in most DART experiments. New implementations and applications with DART are shown in Chapters 5 and 6. In Chapter 5, DART is coupled to multiplexed drift tube ion mobility spectrometry as a potential fieldable platform for the detection of toxic industrial chemicals and chemical warfare agents simulants. In Chapter 6, transmission-mode DART is shown to be an effective method for reproducible sampling from materials which allow for gas to flow through it. Also, Chapter 6 provides a description of a MS imaging platform coupling infrared laser ablation and DART-like phenomena. Finally, in Chapter 7 I will provide perspective on the work completed with DART and the tasks and goals that future studies should focus on.
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Soriano, Joey Kim Tumbali. "Novel plasma-based ambient desorption/ionization source." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13133185/?lang=0, 2020. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13133185/?lang=0.
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周囲プラズマベースの周囲脱離/イオン化ソースにより、従来の大気圧イオン化では不可能な周囲条件下でのサンプルの直接分析が可能になります。これにより、面倒な準備と、多くの有害で複雑なサンプルの分析用質量分析計への導入が解消されます。既存のプラズマベースのアンビエント脱離/イオン化ソースは、通常、2つの電極間にキロヘルツから数メガヘルツの範囲の周波数で直流（DC）または交流（AC）電圧を印加することによって形成されます。この研究では、新しいプラズマベースの周囲脱離/イオン化は、13.56 MHz RFソースから供給される非常に低い電力密度で動作する誘導結合によって生成されたワイヤ安定化大気圧プラズマで構成されています。ワイヤ安定化大気圧プラズマの点火特性、安定性およびプラズマ特性を研究した。Ambient plasma-based ambient desorption/ionization source enables direct analysis of samples under ambient conditions that traditional atmospheric pressure ionization is incapable. It overcomes the tedious preprocessing and often detrimental and complicated sample introduction to the mass spectrometer for analysis. Existing plasma-based ambient desorption/ionization sources feature an electrical discharge typically formed between two electrodes by applying either a direct-current (DC) voltage or an alternating-current (AC) voltage with frequencies ranging from kilohertz to several megahertz. In this study, a novel plasma-based ambient desorption/ionization consists of a wire stabilized atmospheric pressure plasma produced by inductive coupling operated at very low power density supplied by a 13.56 MHz RF source. The ignition characteristics, stability and plasma properties of the wire stabilized atmospheric pressure plasma were studied.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
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Araujo, Gabriel Guarany de. "Resposta biológica de Pseudomonas syringae ao ambiente atmosférico." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-25092018-154659/.
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Pseudomonas syringae produz núcleos de gelo biológicos de grande eficiência. Bioaerossóis destas células tem potencial de participar na glaciação de nuvens, podendo influenciar a precipitação. Foram estudadas como as condições as quais P. syringae está sujeita em suspensão na atmosfera afetam sua sobrevivência e sua atividade de nucleação de gelo. Duas cepas foram testadas, e ambas apresentaram baixa tolerância ao UV-C e ao UV-B, mas exibiram uma maior resistência quando expostas a um espectro semelhante ao encontrado no ambiente. A atividade de congelamento de uma das cepas (pv. syringae) não foi afetada pelo UV, enquanto que para a outra (pv. garcae) houve uma redução moderada. Em resposta à dessecação, pv. garcae foi substancialmente mais resistente que pv. syringae. Isto também afetou a nucleação de gelo das cepas. Em ensaios adicionais, estas bactérias foram expostas em um voo de balão estratosférico, e a uma simulação em laboratório das condições no topo da troposfera. Nestes dois experimentos, sobreviventes protegidos do UV foram recuperados.Pseudomonas syringae produces biological ice nuclei of great efficiency. Bioaerosols of these cells have the potential to take part in cloud glaciation, possibly influencing the precipitation. It was studied how the conditions to which P. syringae is subjected while in suspension in the atmosphere affect its survival and its ice nucleation activity. Two strains were tested, and both showed a low tolerance to UV-C and UV-B, but exhibited a higher resistance when exposed to a spectrum similar to the one found in the environment. The freezing activity of one of the strains (pv. syringae) was not affected by the UV, while that for the other (pv. garcae) there was a moderate reduction. In response to desiccation, pv. garcae was substantially more resistant than pv. syringae. This also affected the ice nucleation by the strains. In additional assays, these bacteria were exposed in a stratospheric balloon flight, and to a laboratory simulation of the conditions at the top of the troposphere. After these two experiments, survivors protected from the UV were recovered.
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Mishra, Nitika. "Characterisation, toxicity and source apportionment of atmospheric organic pollutants in urban schools." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/90055/12/90055%28thesis%29.pdf.
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Airborne organic pollutants have significant impacts on health; however their sources, atmospheric characteristics and resulting human exposures are poorly understood. This research characterized chemical composition of atmospheric volatile organic compounds, polycyclic aromatic hydrocarbons and carbonyls in representative number of primary schools in Brisbane Metropolitan Area, quantified their concentrations, assessed their toxicity and apportioned them to their sources. The findings expand scientific knowledge of these pollutants, and will contribute towards science based management of risks associated with pollution emissions and air quality in schools and other urban and indoor environments.
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Sit, Hoi Leung. "Applications of thermal desorption GCMS analysis of nonpolar organic compounds in source and ambient aerosols /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202008%20SIT.
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Ahmed, Sauda. "Modeling of Ultrafine Particle Emissions and Ambient Levels for the Near Roadside Environment." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3506.
Full textAbstract:
Various epidemiological studies have linked exposure to Ultrafine Particles (UFP; diameter< 100 nm) to adverse health impacts. Roadway traffic is one of the major sources of UFPs and heavily influences UFP concentrations in the nearby vicinity of major roadways. Modeling efforts to predict UFPs have been limited due to the scarcity of reliable information on emissions, lack of monitoring data and limited understanding of complex processes affecting UFP concentrations near sources.
In this study continuous measurement of ultrafine particle number concentrations (PNC) and mass concentrations of nitric oxide (NO), nitrogen dioxide (NO2) and PM2.5 was conducted near an arterial road and freeway at different seasons and meteorological conditions and integrated with traffic count data. PNC showed high correlation with NO (r=0.64 for arterial; 0.61 for freeway), NO2 (r=0.57 for arterial; 0.53 for freeway) and NOx (NOx=NO+NO2; r=0.63 for arterial; 0.59 for freeway) and moderate to low correlation with traffic volume (r=0.33 for arterial; 0.32 for freeway) and PM2.5 (r=0.28 for arterial; 0.23 for freeway); respectively; for both sites at 15 minute averages. The PNC-NOx relationship prevailed on a shorter term (15 min), hourly, and throughout the day basis. Both PNC and NOx showed comparatively higher correlation with traffic during the morning period but became lower during evening which can be attributed to the higher boundary layer and wind speeds. The variable meteorology in the evening affects both PNC and NOx concentrations in the same way and the correlation between NOx and PNC is maintained high both during morning (r=0.74 for arterial; 0.69 for freeway), and evening (r=0.62 for arterial; 0.59 for freeway) periods. Thus nitrogen oxides can be used as a proxy for traffic-related UFP number concentration reflecting the effect of both traffic intensity and meteorological dilution.
The PNC-NOx relation was explored for various meteorological parameters i.e. wind speed and temperature. It is found that NOx emission is temperature independent and can be used to reflect the effect of traffic intensity and meteorological dilution. Once the effect of traffic intensity and dilution is removed, the effect of temperature on PNC-NOx ratio becomes important which can be attributed to the variation in PNC emission factors with temperature.
The high morning PNC-NOx ratio found at the arterial road is a result of new particle formation due to lower temperature and low concentration of exhaust gases in the morning air favoring nucleation over condensation. This finding has important implication when calculating emission factors for UFP number concentrations. Thus it can be concluded that roadside concentration of ultrafine particles not only depends on traffic intensity but also on meteorological parameters affecting dilution or new particle formation. High concentrations of ultrafine particle number concentration close to a roadway is expected due to higher traffic intensity , as well as during low wind speed causing low dilution and low temperature conditions favoring new particle formation.
Finally a simplified approach of calculating particle number emission factor was developed using existing and easily available emission inventory for traffic related tracer gases. Using NOx emission factors from MOVES emission model, the emission ratio of PNC to NOx was converted to develop particle number emission factors. NOx was selected as the traffic related tracer gas since the number concentration of particles is closely correlated to NOx, NOx and particles are diluted in the same way and NOx emission factors are available for a variety of traffic situations. To ensure contribution of fresh traffic exhaust, the average of the difference of pollutant concentrations at high traffic condition and background condition was used to calculate PNC-NOX ratio. Using nitrogen oxides to define background and high-traffic conditions and MOVES emission factor for NOX to convert corresponding PNC-NOX ratio, an average emission factor of (1.82 ± 0.17) E+ 14 particle/ vehicle-km was obtained, suitable for summertime. When compared to existing particle number emission factors derived from dynamometer tests, it was found that there exits reasonable agreement between the calculated real world particle number emission factors and emission factors from dynamometer tests.
The calculated emission factor and R-Line dispersion model was tested in predicting near-road particle number concentrations. Although only 23% of the variability in PNC was explained by the dispersion model, 84.33% of the measurements fell within the factor of two envelope. This suggests that there is potential to effectively use these models and thus warrants more in-depth analysis. Finally, a simple map of PNC gradients from major roads of Portland was developed.
The results of this study helped identify proxy-indicators to provide reference values for estimating UFP concentrations and emissions that can be used for simple evaluation of particle concentration near major roadways for environmental and urban planning purposes and to assess expected impact of UFP pollution on population living near roadways exposed to elevated concentrations.
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Rizzatti, Cláudia Bach. "O AMBIENTE ORGANIZACIONAL: SATISFAÇÃO E COMPETITIVIDADE - UMA ÓTICA DA ENGENHARIA DE PRODUÇÃO." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/8296.
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When contacting an organizational environment, many factors influence the perception and
reading this site. These factors might be considered as clues and it is through them that the
customer satisfaction occurs. However, few studies have been conducted to evaluate the
relationship of organizational atmosphere with consumer satisfaction in the aspect of
competitiveness. Under this bias, picked up a retail company located in Santa Maria to make it
possible to examine this issue. The aim of this study is to assess the contribution of the
environment along with the organizational atmosphere for customer satisfaction in the aspect
of competitiveness. The research is characterized as qualitative and quantitative. For the
qualitative phase, we observed the ten environments stores as the theoretical model of Baker
(1987). For the quantitative phase, we calculated the survey sample, taking into account the
average annual demand of the organization. The minimum sample size of 367 was found.
From the extensive analysis of the results, we can confirm that there is indeed a direct
contribution of the environment to consumer satisfaction beyond that, it became possible to
evaluate the environment can be a deciding factor at the time of decision making by client,
which makes it a contributor to a competitive advantage towards an organization and its
competitors.Ao entrar em contato com um ambiente organizacional, diversos fatores influenciam a percepção e leitura deste local. Fatores esses que podem ser considerados como pistas e será através delas que a satisfação do consumidor ocorrerá. Entretanto, poucos estudos têm sido realizados para avaliar a relação da atmosfera organizacional com a satisfação do consumidor sob o aspecto da competitividade. Sob esse viés, escolheu-se uma empresa de varejo localizada na cidade de Santa Maria para que se faça possível uma análise deste assunto. O objetivo geral deste estudo é verificar a contribuição do ambiente juntamente com a atmosfera organizacional para a satisfação do consumidor sob o aspecto da competitividade. A pesquisa caracteriza-se como qualitativa e quantitativa. Para a fase qualitativa, observaram-se os dez ambientes das lojas conforme o modelo teórico de Baker (1987). Para a fase quantitativa, calculou-se a amostra da pesquisa, levando em consideração a média da demanda anual da organização. A amostra mínima encontrada foi de 367 respondentes. A partir da extensa análise dos resultados, pode-se confirmar que há de fato uma contribuição direta do ambiente com a satisfação do consumidor além de que, se fez possível avaliar que o ambiente poderá ser um fator decisivo na hora da tomada de decisão por parte do cliente, o que torna o mesmo um contribuinte para um diferencial competitivo perante uma organização e seus concorrentes.
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Fahrni, Jason K. "Assessment of the Severity, Sources, and Meteorological Transport of Ambient and Wet Deposited Mercury in the Ohio River Valley Airshed." Ohio University / OhioLINK, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1125427320.
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Rodrigues, Sandrina Azevedo. "Lichen biodiversity and biomonitoring of atmospheric pollution." Doctoral thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/8562.
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Doutoramento BiologiaEsta tese debruça-se sobre a biodiversidade de líquenes epífitos de pinhais dunares portugueses e sobre uso de líquenes como biomonitores de poluição atmosférica nesse habitat. A Mata Nacional das Dunas de Quiaios (Figueira da Foz) foi o ponto de partida dos estudos de biodiversidade efetuados nesta tese, mas alguns deles estenderam-se à maior parte da costa portuguesa. Como resultado, encontrou-se uma espécie nova para a ciência, Lecanora sorediomarginata Rodrigues, Terrón & Elix, epifítica sobre Pinus pinaster Aiton e P. pinea L, que se encontra distribuída na maior parte da costa. Esta espécie caracteriza-se morfologicamente por um talo crustáceo, de cor esbranquiçada a acinzentada ou esverdeada e que desenvolve sorálios a partir de pequenas verrugas marginais. Quimicamente caracteriza-se pela presença dos ácidos 3,5-dicloro-2'-O-metilnorestenospórico [maior], 3,5-dicloro-2-O-metilanziaico [menor], 3,5-dicloro-2-O-metilnordivaricático [menor], 5-cloro-2'-Ometilanziaico [traço] e úsnico [traço]; atranorina [menor] e cloroatranorina [menor]. É quimicamente semelhante a L. lividocinerea Bagl., com a qual apresenta afinidades filogenéticas com base na análise da sequência ITS do rDNA, e a L. sulphurella Hepp. Adicionalmente, espécies Chrysothrix flavovirens Tønsberg e Ochrolechia arborea (Kreyer) Almb, também se encontraram epifíticas sobre P. pinaster e P. pinea em vários pinhais ao longo da costa, representando novos registos para a flora liquénica portuguesa, bem como a espécie Lepraria elobata Tønsberg encontrada epifítica sobre P. pinaster apenas nas Dunas de Quiaios. Além disso, as espécies Hypotrachyna lividescens (Kurok.) Hale e H. pseudosinuosa (Asahina) Hale encontraram-se epifíticas sobre P. pinaster e outros forófitos nas Dunas de Quiaios, constituindo novos registos para a flora liquénica da Península Ibérica. Estes resultados põe em evidência a importância dos pinhais dunares como habitat para líquenes epífitos. Num estudo conduzido entre janeiro e julho de 2008 num pinhal dunar (Mata do Urso, Figueira da Foz), em cuja bordadura existe uma fábrica de celulose de papel, usaram-se transplantes de líquenes da espécie Flavoparmelia caperata (L.) Hale para avaliar a acumulação de trinta e três elementos putativamente emitidos por fábricas de papel e pasta de papel. A cinética da fluorescência da clorofila a foi estudada nos líquenes transplantados, através da análise dos parâmetros Fv/Fm, F0, Fm, qP, NPQ, PSII, e Exc, de forma a avaliar os efeitos decorrentes da acumulação de elementos na vitalidade dos líquenes. Pretendeu-se avaliar se a acumulação de elementos e a cinética da fluorescência da clorofila a variavam significativamente com o local e o tempo de exposição, tendo em consideração os resultados obtidos de transplantes colocados num local de referência (Dunas de Quiaios) durante o mesmo período de tempo. (Continua no verso) resumo A maior parte dos elementos — Al, B, Ba, Ca, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, P, S, Sb, Sc, Sr, Ti e V — ocorreu em concentrações significativamente mais elevadas nos transplantes expostos a 500 m da fábrica. Cerca de metade dos elementos estudados — B, Ba, Cr, Fe, Hg, Mg, Mn, Mo, Na, P, Pb, S, Sb e V — encontraram-se em concentrações significativamente mais elevadas nos transplantes expostos durante 180 dias. O solo foi identificado como uma fonte parcial da maior parte dos elementos. Os parâmetros Fv/Fm, Fm, PSII e Exc variaram significativamente com o local e/ou com o tempo de exposição. Observou-se um decréscimo significativo nos parâmetros Fv/Fm e Fm nos transplantes expostos a 500 e 1000 da fábrica, e também naqueles expostos durante 135 e 180 dias. Observou-se também um decréscimo significativo nos parâmetros PSII e Exc expostos durante 180 dias. Estes parâmetros correlacionaram-se de forma negativa e significativa com a acumulação de elementos: Fv/Fm: B, Ba, Co, Fe, Hg, Mg, Mn, Mo, N, P, S, Sb e Zn; Fm: Ba, Co, Hg, Mn, Mo, N, P, S, Sb e Zn; PSII: N e P; Exc: Mn, N, P e S. Estudos acerca da diversidade liquénica efetuados nos mesmos locais onde os transplantes foram colocados no local impactado, revelaram um menor valor de diversidade liquénica a 500 m da fábrica, que foi também o único local onde se encontraram espécies nitrófilas, o que se poderá dever à deposição de amónia e/ou poeiras. À semelhança de outros estudos, este trabalho confirma que os líquenes podem ser usados com sucesso em estudos de biomonitorização, mesmo em locais florestados. Além disso, traz também informações adicionais sobre como a acumulação de elementos pode influenciar a cinética da fluorescência da clorofila a em líquenes.
This thesis focuses on the biodiversity of epiphytic lichens of Portuguese pine forests on sand dunes, and on the use of lichens as biomonitors of atmospheric pollution in this habitat. Mata Nacional das Dunas de Quiaios (Figueira da Foz) was the starting location of the biodiversity studies undertaken during this thesis, but some were extended to most of the Portuguese coast. As a result a new species to science, Lecanora sorediomarginata Rodrigues, Terrón & Elix was discovered epiphytic on Pinus pinaster Aiton and P. pinea L, in most of the coast. It is characterised morphologically by a crustose whitish-grey to greenish thallus developing soralia from small, marginal warts and chemically by the presence of 3,5-dichloro-2'-O-methylnorstenosporic acid [major], 3,5-dichloro- 2-O-methylanziaic acid [minor], 3,5-dichloro-2-O-methylnordivaricatic acid [minor], 5-chloro-2'-O-methylanziaic acid [trace], atranorin [minor], chloroatranorin [minor], and usnic acid [trace]. It is chemically similar to L. lividocinerea Bagl., to which it shows phylogenetic affinities based on ITS rDNA sequence analysis, and to L. sulphurella Hepp. Additionally, Chrysothrix flavovirens Tønsberg and Ochrolechia arborea (Kreyer) Almb, were also found epiphytic on P. pinaster and P. pinea in several pine forests along the coast, representing new records for Portuguese lichen flora, as well as that of Lepraria elobata, which was found epiphytic on P. pinaster only at Dunas de Quiaios. Furthermore, Hypotrachyna lividescens (Kurok.) Hale e H. pseudosinuosa (Asahina) Hale were found epiphytic on P. pinaster and other phorophytes at Dunas de Quiaios, and were new records for the lichen flora of the Iberian Peninsula. These results indicate the importance of pine forests on sand dunes has habitats for epiphytic lichens. In a study conducted in a pine forest on sand dunes (Mata do Urso, Figueira da Foz), impacted by a pulp mill at its border, between January and July 2008, lichen transplants of the species Flavoparmelia caperata (L.) Hale were used to evaluate the accumulation of thirty-three elements putatively emitted by paper and pulp mill industry. Chlorophyll a fluorescence kinetics studies were performed in the transplanted lichens, through the analysis of the parameters Fv/Fm, F0, Fm, qP, NPQ, PSII, and Exc in order to evaluate the effect of elemental accumulation on lichen vitality. It was intended to evaluate if elemental accumulation and chlorophyll a fluorescence kinetics varied significantly with site and period of exposure, taking into account the results from transplants performed in a reference location (Dunas de Quiaios) during the same period of time. Most elements — Al, B, Ba, Ca, Co, Cr, Cu, Fe, Hg, Li, Mg, Mn, Mo, Na, Ni, P, S, Sb, Sc, Sr, Ti and V — were found in significantly higher concentrations in the transplants exposed at 500 m of distance from the point source. Nearly half of the elements — B, Ba, Cr, Fe, Hg, Mg, Mn, Mo, Na, P, Pb, S, Sb, and V — were also found in significantly higher concentrations in the transplants exposed during 180 days. (Continues on the verse) abstract Soil was identified as a partial source for most elements. The chlorophyll a fluorescence kinetics parameters Fv/Fm, Fm, PSII, and Exc varied significantly with site and/or period of exposure. Fv/Fm and Fm were significantly decreased in the transplants exposed at 500 and 1000 m from the pulp mill and in those exposed during 135 and 180 days. Both, PSII and Exc decreased significantly after 180 days of exposure. Significant negative correlations were identified between these parameters and the accumulation of elements: Fv/Fm: B, Ba, Co, Fe, Hg, Mg, Mn, Mo, N, P, S, Sb, and Zn; Fm: Ba, Co, Hg, Mn, Mo, N, P, S, Sb, and Zn; PSII: N and P; Exc: Mn, N, P, and S. Lichen diversity studies performed in the same locations where lichen transplants were placed at the impacted location revealed a lower lichen diversity value at the 500 m, which was also the only site were nitrophylous species were found, what could be due to the deposition of ammonia and/or dust. Similarly to other studies, this work confirms that lichens can be successfully used in biomonitoring studies, even in forested locations. Furthermore, it provides additional information on how chlorophyll a fluorescence kinetics of lichens can be influenced by elemental accumulation.
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DUPUIS, HELENE. "Etude des parametres geophysiques de l'interface ocean-atmosphere a l'aide de mesures de bruit ambiant sous-marin a partir d'un hydrophone." Paris 7, 1992. http://www.theses.fr/1992PA077239.
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Le bruit ambiant sous-marin, enregistre a partir d'un hydrophone, permet l'estimation de parametres geophysiques de l'interface ocean/atmosphere tels que la vitesse moyenne du vent ou sa vitesse de frottement et la densite moyenne de vagues deferlantes a la surface de l'eau. Differents sites experimentaux ont fait l'objet d'etudes, que ce soit en eau tres peu profonde (etang), intermediaire (zone cotiere) ou profonde (mediterranee). La definition des conditions experimentales doit etre concue de maniere a eviter la contamination du bruit ambiant lie a l'agitation de la surface par d'autres sources acoustiques telles que les bateaux et la faune aquatique. Les donnees de ces differentes experiences ont tout d'abord permis de verifier les hypotheses du modele de propagation acoustique sous-marine developpe afin de simuler le bruit ambiant sous-marin. Grace a ce modele, il est possible d'estimer les caracteristiques du bruit sous-marin en fonction des conditions de mesure, telles que la profondeur d'immersion de l'hydrophone, celle du fond sous-marin, les caracteristiques de ce fond et la frequence acoustique consideree. On peut en particulier etablir la valeur du rayon d'ecoute de la mesure, equivalent au rayon du disque de la surface d'ou est emise la quasi-totalite du bruit recu par l'hydrophone. Il est ainsi possible de definir la representativite de l'echelle spatiale d'estimation des parametres de surface. Une etude approfondie a ete menee par verifier la relation statistique entre le bruit et le vent pour l'experience en etang. On a ainsi pu montrer que la correlation etait bonne pour des echelles de temps tres courtes (<1 mn). De plus, le parametre defini par l'acceleration du vent semble aussi intervenir et sa prise en compte pourrait encore ameliorer la relation statistique. En ce qui concerne la repartition des zones de deferlement a la surface, le modele permet de definir a la fois l'evolution de la densite de vagues deferlantes et celle des dimensions moyennes des nuages de bulles en fonction des conditions de vent. Pour l'experience en etang pendant laquelle la vitesse du vent a varie entre 0 et 6 m/s, aucune variation de la dimension des zones de deferlement n'a ete observee. Il en resulte que la densite des vagues deferlantes est proportionnelle a la vitesse du vent au carre. Pour estimer ces parametres, il est preferable que le rayon d'ecoute soit relativement important par rapport a la longueur d'onde des vagues dominantes (>>100 m). Par contre, lorsque le rayon d'ecoute est relativement faible, il est possible d'etudier le degre d'organisation du champ de vagues et le processus de repetition du deferlement lie aux ondes de groupes des vagues
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Fontenele, Maria Alves. "ConservaÃÃo pÃs-colheita do bacuri sob condiÃÃes ambiente e refrigeraÃÃo associada à atmosfera modificada." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1509.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoEste trabalho teve por objetivos verificar atravÃs da caracterizaÃÃo de frutos do bacurizeiro da RegiÃo do Meio Norte, quais as melhores condiÃÃes de atmosfera, de tempos e temperaturas de armazenamento, para prolongar a vida pÃs - colheita do bacuri (Platonia insignis Mart) para comercializaÃÃo in natura. Os frutos colhidos na planta, armazenados sob atmosfera modificada apresentaram Ãtima aparÃncia externa e interna atà o final do experimento (25 dias), enquanto que os armazenados sob atmosfera ambiente tiveram sua aparÃncia externa comprometida apÃs o sexto dia, entretanto sua aparÃncia interna foi satisfatÃria atà o final do experimento. A perda de massa foi maior nos frutos sem filme, com perdas de atà 47% aos 25 dias de armazenamento, contra 8% nos frutos com filme. A qualidade fÃsico-quimica da polpa foi pouco afetada durante o armazenamento com destaque para os sÃlidos solÃveis totais que apresentaram menor percentual nos frutos com filme. Os frutos colhidos na planta, armazenados a 7 ÂC em atmosfera modificada tiveram sua aparÃncia externa comprometida apÃs 20 dias, por injÃrias pelo frio, enquanto que nas temperaturas de 9 e 11 ÂC a vida Ãtil foi de 36 dias. A coloraÃÃo das frutas evoluiu de verde claro para amarelo apenas nas temperaturas de 9 e 11 ÂC, sendo que a 11 ÂC a coloraÃÃo atingiu uma maior intensidade. A qualidade da polpa praticamente nÃo foi afetada pelas temperaturas de armazenamento. Os frutos apanhados apÃs caÃrem da planta, armazenados a temperatura ambiente e atmosfera modificada tiveram sua aparÃncia externa comprometida no dÃcimo nono dia de armazenamento e a interna apÃs 21 dias. Jà para os frutos armazenados sob refrigeraÃÃo e atmosfera modificada, a aparÃncia externa foi comprometida aos 28 dias de armazenamento, apesar de apresentar aparÃncia interna satisfatÃria atà o trigÃsimo quinto dia. A perda de massa foi de 7,74% e 2,17%, nos frutos armazenados a 25 ÂC e 12 ÂC, respectivamente. Os frutos armazenamento a temperatura ambiente tiveram rendimento em torno de 16%, enquanto, que os frutos armazenados sob refrigeraÃÃo o rendimento foi de 15%. Os valores dos SST decresceram durante o armazenamento nas duas temperaturas avaliadas. ApÃs 35 dias de armazenamento a 25 ÂC os frutos apresentaram em mÃdia 12,12 ÂBrix, enquanto que a 12 ÂC apÃs 42 dias de armazenamento apresentaram um valor de 11,28 ÂBrix. Os valores de pH apresentaram pouca variaÃÃo atravÃs do tempo nas duas condiÃÃes de armazenamento e a AT obteve maior variaÃÃo no armazenamento a 25 ÂC. A relaÃÃo SST/AT apresentou variaÃÃes considerÃveis entre o inicio e o final nos dois tipos de armazenamento, sendo mais intenso no armazenamento a temperatura ambiente. Os frutos apresentaram baixos teores de compostos fenÃlicos em todas as fraÃÃes caracterizando a polpa de bacuri como pouco adstringente, demonstrando potencial para consumo in natura, alÃm de pouco teor de vitamina C, nas duas condiÃÃes de armazenamento.
This work had for objectives to verify through the characterization of fruits of the bacuri tree of the Area of the North Middle, which the best atmosphere conditions, of times and storage temperatures, to prolong the life post-harvest of the bacuri (Platonia insignis Mart) for commercialization in natura. The fruits picked in the plant, stored under modified atmosphere they presented great appearance it expresses and it interns until the end of the experiment (25 days), while stored them under atmosphere it adapts they had your appearance it expresses committed after the sixth day, however your internal appearance was satisfactory until the end of experiment. A mass loss it was larger in the fruits without film, with losses of up to 47% to the 25 days of storage, against 8% in the fruits with film. The physical-chemical quality of the pulp was little affected during the storage with prominence for the total soluble solids that presented smaller percentile in the fruits with film. The fruits picked in the plant, stored 7 ÂC in modified atmosphere they had your appearance it expresses committed after 20 days, for offenses for the cold, while in the temperatures of 9 and 11 ÂC useful life was of 36 days. The coloration of the fruits just developed of clear green for yellow in the temperatures of 9 and 11 ÂC, and to 11 ÂC the coloration reached a larger intensity. The quality of the pulp practically was not affected by the storage temperatures. The fruits been hit after you/they fall of the plant, stored the temperature it adapts and modified atmosphere had your appearance it expresses committed in the nineteenth day of storage and the intern after 21 days, already for the fruits stored under refrigeration and modified atmosphere, the appearance expresses it was committed to the 28 days of storage, in spite of presenting satisfactory internal appearance until the thirtieth fifth day. The mass loss was of 7.74% and 2.17%, in the fruits stored 25 ÂC and 12 ÂC, respectively. The fruits storage the temperature adapts they had revenue around 16%, while, that the fruits stored under refrigeration the revenue it was of 15%. The values of SST decreased during the storage in the two appraised temperatures. After 35 days of storage to 25 ÂC the fruits presented 12.12 ÂBrix on average, while to 12 ÂC after 42 days of storage presented a value of 11.28 ÂBrix. The values of the pH presented little variation through the time in the two storage conditions and the AT obtained larger variation in the storage to 25 ÂC. The relationship SST/AT presented considerable variations among I begin him/it and the end in the two storage types, being more intense in the storage the temperature adapts. The fruits presented low tenors of phenolic compounds in all the fractions characterizing the bacuri pulp as little astringent, demonstrating potential so much for consumption in natura, besides little vitamin tenor C, in the two storage conditions.
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Fontenele, Maria Alves. "Conservação pós-colheita do bacuri sob condições ambiente e refrigeração associada à atmosfera modificada." reponame:Repositório Institucional da UFC, 2007. http://www.repositorio.ufc.br/handle/riufc/17777.
Full textAbstract:
FONTENELE, Maria Alves. Conservação pós-colheita do bacuri sob condições ambiente e refrigeração associada à atmosfera modificada. 2007. 138 f. : Dissertação (mestrado) - Universidade Federal do Ceará,Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007,Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:32:55Z No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5)
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This work had for objectives to verify through the characterization of fruits of the bacuri tree of the Area of the North Middle, which the best atmosphere conditions, of times and storage temperatures, to prolong the life post-harvest of the bacuri (Platonia insignis Mart) for commercialization in natura. The fruits picked in the plant, stored under modified atmosphere they presented great appearance it expresses and it interns until the end of the experiment (25 days), while stored them under atmosphere it adapts they had your appearance it expresses committed after the sixth day, however your internal appearance was satisfactory until the end of experiment. A mass loss it was larger in the fruits without film, with losses of up to 47% to the 25 days of storage, against 8% in the fruits with film. The physical-chemical quality of the pulp was little affected during the storage with prominence for the total soluble solids that presented smaller percentile in the fruits with film. The fruits picked in the plant, stored 7 ºC in modified atmosphere they had your appearance it expresses committed after 20 days, for offenses for the cold, while in the temperatures of 9 and 11 ºC useful life was of 36 days. The coloration of the fruits just developed of clear green for yellow in the temperatures of 9 and 11 ºC, and to 11 ºC the coloration reached a larger intensity. The quality of the pulp practically was not affected by the storage temperatures. The fruits been hit after you/they fall of the plant, stored the temperature it adapts and modified atmosphere had your appearance it expresses committed in the nineteenth day of storage and the intern after 21 days, already for the fruits stored under refrigeration and modified atmosphere, the appearance expresses it was committed to the 28 days of storage, in spite of presenting satisfactory internal appearance until the thirtieth fifth day. The mass loss was of 7.74% and 2.17%, in the fruits stored 25 ºC and 12 ºC, respectively. The fruits storage the temperature adapts they had revenue around 16%, while, that the fruits stored under refrigeration the revenue it was of 15%. The values of SST decreased during the storage in the two appraised temperatures. After 35 days of storage to 25 ºC the fruits presented 12.12 ºBrix on average, while to 12 ºC after 42 days of storage presented a value of 11.28 ºBrix. The values of the pH presented little variation through the time in the two storage conditions and the AT obtained larger variation in the storage to 25 ºC. The relationship SST/AT presented considerable variations among I begin him/it and the end in the two storage types, being more intense in the storage the temperature adapts. The fruits presented low tenors of phenolic compounds in all the fractions characterizing the bacuri pulp as little astringent, demonstrating potential so much for consumption in natura, besides little vitamin tenor C, in the two storage conditions.
Este trabalho teve por objetivos verificar através da caracterização de frutos do bacurizeiro da Região do Meio Norte, quais as melhores condições de atmosfera, de tempos e temperaturas de armazenamento, para prolongar a vida pós - colheita do bacuri (Platonia insignis Mart) para comercialização in natura. Os frutos colhidos na planta, armazenados sob atmosfera modificada apresentaram ótima aparência externa e interna até o final do experimento (25 dias), enquanto que os armazenados sob atmosfera ambiente tiveram sua aparência externa comprometida após o sexto dia, entretanto sua aparência interna foi satisfatória até o final do experimento. A perda de massa foi maior nos frutos sem filme, com perdas de até 47% aos 25 dias de armazenamento, contra 8% nos frutos com filme. A qualidade físico-quimica da polpa foi pouco afetada durante o armazenamento com destaque para os sólidos solúveis totais que apresentaram menor percentual nos frutos com filme. Os frutos colhidos na planta, armazenados a 7 ºC em atmosfera modificada tiveram sua aparência externa comprometida após 20 dias, por injúrias pelo frio, enquanto que nas temperaturas de 9 e 11 ºC a vida útil foi de 36 dias. A coloração das frutas evoluiu de verde claro para amarelo apenas nas temperaturas de 9 e 11 ºC, sendo que a 11 ºC a coloração atingiu uma maior intensidade. A qualidade da polpa praticamente não foi afetada pelas temperaturas de armazenamento. Os frutos apanhados após caírem da planta, armazenados a temperatura ambiente e atmosfera modificada tiveram sua aparência externa comprometida no décimo nono dia de armazenamento e a interna após 21 dias. Já para os frutos armazenados sob refrigeração e atmosfera modificada, a aparência externa foi comprometida aos 28 dias de armazenamento, apesar de apresentar aparência interna satisfatória até o trigésimo quinto dia. A perda de massa foi de 7,74% e 2,17%, nos frutos armazenados a 25 ºC e 12 ºC, respectivamente. Os frutos armazenamento a temperatura ambiente tiveram rendimento em torno de 16%, enquanto, que os frutos armazenados sob refrigeração o rendimento foi de 15%. Os valores dos SST decresceram durante o armazenamento nas duas temperaturas avaliadas. Após 35 dias de armazenamento a 25 ºC os frutos apresentaram em média 12,12 ºBrix, enquanto que a 12 ºC após 42 dias de armazenamento apresentaram um valor de 11,28 ºBrix. Os valores de pH apresentaram pouca variação através do tempo nas duas condições de armazenamento e a AT obteve maior variação no armazenamento a 25 ºC. A relação SST/AT apresentou variações consideráveis entre o inicio e o final nos dois tipos de armazenamento, sendo mais intenso no armazenamento a temperatura ambiente. Os frutos apresentaram baixos teores de compostos fenólicos em todas as frações caracterizando a polpa de bacuri como pouco adstringente, demonstrando potencial para consumo in natura, além de pouco teor de vitamina C, nas duas condições de armazenamento.
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Rizzo, Luciana Varanda. "Modelamento dos processos de conversão gás-partícula e de formação de núcleos de condensação de nuvens na Amazônia." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-15042014-121728/.
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A região amazônica constitui um complexo ecossistema, integrando a floresta, o sistema hídrico e a atmosfera. A região tem passado por profundas mudanças no uso do solo, com a troca de floresta por pastagens e culturas agrícolas, alterando o funcionamento natural do ecossistema. Tais alterações vêm sendo estudadas pelo Experimento de Grande Escala da Biofera-Atmosfera na Amazônia (LBA). Fazendo uso do modelo MAPS (Model for Aerosol Process Studies), do tipo caixa de dimensão zero, foram simulados os processos dinâmicos de produção de aerossóis orgânicos a partir de precursores gasosos (VOCs - Volatile Organic Compounds), e da formação de núcleos de condensação de nuvens (CCN - Cloud Condensation Nuclei) na Amazônia. Os resultados deste trabalho mostram que o processo de conversão gás-partícula altera as propriedades físico-químicas da população de aerossóis e CCNs. A oxidação dos monoterpenos, compostos orgânicos voláteis emitidos pela vegetação, leva à produção de aerossóis secundários na moda fina. A conversão de floresta para pastagem reduz as emissões de monoterpenos, com uma conseqüente diminuição na produção de novas partículas orgânicas. Em 24 horas de simulação, o modelo MAPS calcula uma concentração de 2.0 ug/m POT.3 de aerossóis orgânicos secundários para o ambiente de floresta, em comparação com o valor de 0.69 ug/m POT.3 previsto para o ambiente de pastagem. A produção de aerossóis orgânicos secundários, devido à conversão gás-partícula, traz conseqüências para os processos de produção de CCN e formação de nuvens. A partir de uma população natural de aerossóis constituída majoritariamente por compostos orgânicos, o modelo prevê a ativação de 90% das partículas à supersaturação de 0.5%, evidenciando o papel dos aerossóis biogênicos orgânicos no processo de formação de nuvens na Amazônia. O material particulado das estações seca e chuvosa da Amazônia apresenta características muito diversas, ) no que diz respeito à distribuição de tamanho e de espécies químicas. A partir das propriedades físico-químicas dos aerossóis de queimadas, o modelo calculou uma concentração de 250 partículas de CCN por cm POT.3 a uma supersaturação de 0.15%, em oposição às 100 partículas de CCN por cm POT.3 produzidas a partir de aerossóis naturais, sob condições idênticas de umidade. A maior quantidade de CCNs na estação seca interfere nos processos físicos de produção de nuvens, podendo provocar uma diminuição da taxa de crescimento de gotas, um aumento no tempo de residência das nuvens, e a conseqüente redução da taxa de precipitação na Amazônia.The Amazon Forest is a very complex ecosystem, which integrates its vegetation, its hydrological system, and the atmosphere. The Amazonian vegetation, with its natural metabolism, emits a large amount of biogenic particles and trace gases to the atmosphere. The region is passing through deep changes with respect to land use and land cover. The conversion of forest to pasture or agricultural land alters the ecosystem natural behavior. Using a zero dimensional box model named MAPS (Model for Aerosol Processes Studies),the dynamical processes of gas-to-particle conversion and cloud condensation nuclei (CCN) formation have been simulated for Amazonia. The parameters that constraint the model were based on data collected during the Large Biosphere-Atmosphere Experiment in Amazon (LBA). This work shows that gas-to-particle conversion processes affects the physical and chemical properties of natural aerosol population. Oxidation of monoterpenes, volatile organic compounds emitted by vegetation, causes a fine mode secondary organic aerosol production. The conversion of forest to pasture land reduces monoterpene emissions, diminishing the production of new organic particles as consequence. In 24 hours of simulation, the model predicts a secondary organic aerosol concentration of 2.0 g/m³ for forest, and 0.69 g/m³ for pasture environment. The production of secondary organic aerosol, due to gas-to-particle conversion, influences CCN population and cloud processes formation. From a natural aerosol population composed mainly by organic compounds, the model predicts that 90% of the particles activates at 0.5% of ambient supersaturation, showing the important role of organic aerosol on CCN formation in Amazon. Dry and wet season particulate matter in Amazonia shows very distinct characteristics of size and chemical species distribution. From a typical burning season aerosol, the model predicted a concentration of 250 CCN/cm³ at a supersaturation of 0.15%. With similar humidity conditions, a concentration of 100 CCN/cm³ was calculated from natural wet season aerosol. The increased number of CCN during the dry season affects cloud formation, and can reduce the growth rate of droplets, enlarge cloud lifetime, and consequently diminish cloud precipitation rates.
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Brüggemann, Martin [Verfasser]. "Development, characterization, and application of flowing atmospheric-pressure afterglow ionization for mass spectrometric analysis of ambient organic aerosols / Martin Brüggemann." Mainz : Universitätsbibliothek Mainz, 2015. http://d-nb.info/1079036709/34.
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Jorge, Danilo Custódio. "Particulate carbon in the atmosphere: distribution aging and wet deposition." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16829.
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Doutoramento em Ciências e Engenharia do AmbienteDuring the last decades a significant number of studies was performed about the cycling of carbonaceous matter in the atmosphere. Despite the efforts of the scientific community, a full understanding about the composition and formation of carbonaceous aerosol in ambient air was not yet achieved, reflecting the great variety of emitting sources and the complexity of transformation processes in the atmosphere. In addition, very little is known about a specific type of carbonaceous aerosol: the indoor carbonaceous aerosol. Removal of particulate carbonaceous matter from the atmosphere is another component of the carbon cycle that has received poor attention from researchers. The main aim of this work was to contribute to a better understanding of the sources, transformation processes and removal of atmospheric carbonaceous matter. Particulate matter, organic carbon (OC) and elemental carbon (EC) concentrations were measured simultaneously in the indoor and outdoor air of residences located in urban and sub-urban areas of northwestern Mainland Portugal. Average indoor to outdoor ratios (I/O) for OC were higher than 1 in occupied residences, showing that indoor sources, such as cooking, smoking, biomass burning and movement of people, strongly influenced indoor OC concentrations. In contrast, I/O ratios for EC were close to 1, except for a smokers’ residence, suggesting that indoor concentrations were mainly controlled by outdoor sources, most likely from vehicular emissions and biomass burning. Aerosol composition was also evaluated during one year in a kerbside site located in a busy road of Oporto. Road traffic, local dust and biomass burning were found to be the most important sources of aerosol particles. Most of the aerosol constituents exhibited well-defined temporal variations, which were related with the seasonal variability of source strengths, atmospheric processes and climatic conditions. In addition, precipitation samples were collected and characterized for chemical constituents at a background site in the Azores Islands and an urban site in the city of Oporto. Transport from continental areas bordering the North Atlantic Ocean were the main source of EC in the Azores. Both local emissions and long-range transport explained the levels of water soluble organic carbon found in the same samples. Concentrations of carbonaceous matter in Oporto were considerably higher than those measured before in other background areas in Portugal, indicating a significant atmospheric contamination by anthropogenic activities.
Nas últimas décadas foram desenvolvidos vários estudos sobre a circulação atmosférica da matéria carbonácea. Contudo, apesar dos esforços da comunidade científica, não se conseguiu ainda compreender detalhadamente a composição e a formação do aerossol carbonáceo no ar ambiente, o que reflete a grande variedade de fontes emissoras e a complexidade dos processos de transformação que ocorrem na atmosfera. Acresce ainda que se sabe muito pouco sobre um caso particular do aerossol de carbono: as partículas carbonáceas em suspensão no ar interior. Outra componente do ciclo do carbono que tem merecido pouca atenção da comunidade científica é a remoção das partículas carbonáceas da atmosfera. Este trabalho tem como objetivo principal contribuir para um melhor conhecimento sobre as fontes, processos de transformação e remoção da matéria carbonácea presente na atmosfera. As concentrações de matéria particulada, carbono orgânico (CO) e carbono elementar (CE) foram medidas simultaneamente no ar interior e exterior de residências localizadas em áreas urbanas e sub-urbanas da região nordeste de Portugal Continental. Os valores médios da razão entre as concentrações no ar interior e exterior (I/E) para o CO foram superiores a 1 para as residências com ocupantes, mostrando que as fontes interiores, como a confeção de alimentos, a queima de biomassa e o movimento de pessoas, influenciaram fortemente os teores de CO. Pelo contrário, obtiveram-se valores médios próximos de 1 para a razão I/E do CE, excluindo uma residência de fumadores, sugerindo que as concentrações deste componente eram controladas por fontes externas, muito provavelmente o tráfego automóvel e a queima de biomassa. A composição do aerossol foi também avaliada durante um ano num local confinante com uma estrada de tráfego intenso na cidade do Porto. Verificou-se que as principais fontes emissoras de partículas eram o tráfego automóvel, as poeiras do solo e a queima de biomassa. Muitos dos constituintes do aerossol mostraram variações temporais bem marcadas, as quais foram relacionadas com a variabilidade sazonal das fontes emissoras, dos processos atmosféricos e das condições climáticas. Procedeu-se ainda à recolha de amostras de precipitação e posterior caracterização química num local de fundo do arquipélago dos Açores e num local urbano da cidade do Porto. A principal fonte do CE nos Açores é o transporte a longas distâncias a partir das áreas continentais que envolvem o Atlântico Norte. Os teores de carbono orgânico insolúvel tiveram origem tanto em emissões locais como no transporte a longas distâncias. As concentrações de matéria carbonácea no Porto mostraram-se substancialmente superiores às que tinham sido medidas em áreas remotas de Portugal, indicando uma contaminação significativa por atividades antropogénicas.
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Diert-Boté, Irati. "An exploration of English language learners’ emotions and beliefs in a Catalan context: Insights from self-reported experiences and observed classroom practices." Doctoral thesis, Universitat de Lleida, 2021. http://hdl.handle.net/10803/671527.
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Com a conseqüència del ‘gir emocional’ (Pavlenko, 2013) en el camp d’Adquisició de Segones Llengües – i en particular gràcies a l’arribada de la Psicologia Positiva, s'ha dedicat més atenció al paper que exerceixen les emocions i processos relacionats com les (auto-)creences en l'aprenentatge de segones llengües/llengües estrangeres. L'objectiu d'aquest projecte d'investigació és explorar les creences i emocions que els estudiants d’anglès manifesten i construeixen en relació amb (i) la metodologia d’ensenyament i el tipus de tasques (especialment les tasques orals); i (ii) el paper de les relacions entre professor i alumne. S'ha adoptat un enfocament qualitatiu en quatre estudis independents però entrellaçats, en què s’han analitzat tant dades observacionals (enregistraments d'àudio/vídeo a l'aula) com no observacionals (entrevistes, grups de discussió i ítems de resposta oberta). Els resultats indiquen que molts estudiants han construït autoconceptes insegurs amb (auto)creences disfuncionals i experiències emocionals negatives interrelacionades, especialment pel que fa a les tasques de parla, en gran part a causa d'una tradició d'enfocaments gramaticals i d’escassa producció oral. L'anàlisi mostra que és possible canviar cap a una mentalitat més positiva, però el procés d'adaptació implica períodes difícils de transició per aquells estudiants que semblen sentir-se més insegurs amb les seves habilitats lingüístiques. Durant aquest procés, s’ha demostrat que el paper del professor és crucial per a crear positivitat a classe promovent un contacte positiu entre professor i alumne i creant un entorn segur on els estudiants respectin i treballin col•laborativament per tal de vèncer la inhibició a l’hora de parlar en anglès.A raíz del 'giro emocional' (Pavlenko, 2013) en el campo de Adquisición de Segundas Lenguas – y, en particular, gracias a la llegada de la Psicología Positiva, se ha dedicado más atención al papel que desempeñan las emociones y procesos relacionados como las (auto)creencias en el aprendizaje de segundas lenguas/lenguas extranjeras. El objetivo de este proyecto de investigación es explorar las creencias y emociones que los estudiantes de inglés manifiestan y construyen en relación con (i) la metodología de enseñanza y el tipo de tareas (especialmente las tareas orales); y (ii) el papel de las relaciones entre profesor y alumno. Se ha adoptado un enfoque cualitativo en cuatro estudios independientes pero entrelazados en los cuales se han analizado tanto datos observacionales (grabaciones de audio/vídeo en el aula) como no observacionales (entrevistas, grupos de discusión e ítems de respuesta abierta). Los resultados indican que muchos estudiantes han construido autoconceptos inseguros con (auto)creencias disfuncionales y experiencias emocionales negativas interrelacionadas, especialmente con respecto a las tareas de habla, en gran parte debido a una tradición de enfoques gramaticales y escasa producción oral. El análisis muestra que es posible cambiar hacia una mentalidad más positiva, pero el proceso de adaptación implica períodos difíciles de transición para aquellos estudiantes que parecen sentirse más inseguros con sus habilidades lingüísticas. Durante este proceso, se ha demostrado que el papel del profesor es crucial para crear positividad en clase promoviendo un contacto positivo entre profesor y alumno y creando un entorno seguro donde los estudiantes respeten y trabajen colaborativamente para vencer la inhibición a la hora de hablar en inglés.
Due to the ‘emotional turn’ (Pavlenko, 2013) in SLA – and particularly thanks to the advent of Positive Psychology – closer attention has been devoted to the role that emotions and related processes such as (self-)beliefs play in foreign/second language learning. The aim of this doctoral thesis is to explore the English language learning beliefs and emotions students display and have constructed in relation to (i) the teaching methodology and the type of tasks (particularly oral tasks), and (ii) the role of the teacher and student-teacher relationships. A qualitative approach has been adopted in four independent yet intertwined studies in which both observational (classroom audio/video-recordings) and non-observational (interviews, focus groups and open-ended items) data have been analyzed. Findings indicate that many students have constructed insecure self-concepts with interrelated dysfunctional (self-)beliefs and negative emotional experiences – especially regarding speaking tasks – largely due to a tradition of grammar-based approaches and scarce oral production. The analysis shows that change towards more positive mindsets is possible but the adaptation process involves difficult periods of transition for those students who appear to feel more insecure with their language abilities. During this process, the role of the teacher has been proven to be crucial in fostering positivity in class by promoting positive teacher-student contact and by creating a safe environment in which students respect and work collaboratively in order to overcome English speaking inhibition.
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Van, Drooge Barend L. "Long-range atmospheric transpod and fate of persistent organic pollutants in remote mountain areas." Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/3660.
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Cusack, Michael. "Physical and chemical processes affecting atmospheric aerosols in the Western Mediterranean regional background." Doctoral thesis, Universitat Autònoma de Barcelona, 2013. http://hdl.handle.net/10803/129553.
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En este trabajo se muestra un estudio detallado de las fuentes de emisión y de los procesos físico-químicos que afectan a los aerosoles atmosféricos en el entorno regional de Montseny, situado en el Mediterráneo Occidental, una región relativamente poco estudiada en cuanto a calidad del aire. En el marco de calidad del aire, el estudio de los aerosoles atmosféricos está siendo de gran y creciente interés en la actualidad debido tanto a los potenciales efectos perjudiciales en la salud derivados de la exposición a estos contaminantes, como a sus efectos en el clima. Se ha llevado a cabo el análisis de una extensa serie temporal (2002-2010) de niveles de PM2.5 (material particulado de diámetro menor de 2.5 µm) y de su composición química, con el objetivo de describir las tendencias y fluctuaciones en las concentraciones, así como de identificar las posibles causas de estas variaciones. El análisis de la tendencia temporal de PM2.5 mostró una disminución estadísticamente significativa, generalizada a lo largo de Europa. Esta tendencia de disminución se atribuye a la eficacia de estrategias de reducción de la contaminación aplicadas por los países miembros de la UE, dado que muchos de los compuestos asociados a actividades antropogénicos, como el sulfato, el carbono orgánico y muchos metales traza, muestran un descenso gradual. Por otro lado, también se demostró que parámetros meteorológicos a escala global, como la Oscilación del Atlántico Norte (NAO), pueden regir las tendencias en las concentraciones de PM a través de Europa. En ciertos países, la recesión económica de los últimos años también parece haber afectado a los niveles de contaminantes antropogénicos. Este trabajo incluye la identificación y caracterización de las variaciones diarias y estacionales, así como de las fuentes de emisión, de PM1 (material particulado de diámetro menor de 1 µm) y de partículas sub-micrónicas. Las principales fuentes de emisión incluyen sulfato secundario, aerosol orgánico secundario, combustión de fuel oil, trafico rodado, quema de biomasa, emisiones industriales y nitrato. La formación de nuevas partículas y su posterior crecimiento se identificó como una fuente importante de partículas ultrafinas (partículas menores de 100 nm de diámetro). Durantes lo meses más cálidos las concentraciones de partículas muestran un aumento debido a que los procesos fotoquímicos de formación de partículas se ven favorecidos, las concentraciones de materia mineral son también más elevadas, hecho asociado a procesos de resuspensión del suelo y a intrusiones Saharianas mas frecuentes, se registran niveles más altos de sulfato y de compuestos procedentes del tráfico marítimo como consecuencia de brisas marinas más pronunciadas, y las condiciones son más propicias para la generación de emisiones biogénicas.. Por otro lado, durante los meses más fríos se describen episodios de contaminación intensos a consecuencia de condiciones anticiclónicas que causan el estancamiento de las masas de aire y la acumulación de contaminantes atmosféricos a través de la región. Estos episodios se caracterizan especialmente por niveles elevados de nitrato. La meteorología local, y específicamente la acción de brisas de mar y montaña, se identifican como un agente que controla el transporte de masas de aire contaminadas desde zonas urbanas a zonas rurales, y que rige la variabilidad diaria de aerosoles atmosféricos. Durante los meses fríos, la formación de nuevas partículas se observa en ausencia de una atmósfera contaminada, siempre que exista suficiente radiación solar y los gases precursores necesarios (acido sulfúrico, vapores orgánicos semi-volátiles). Durante los meses cálidos, la formación de nuevas partículas se observa con mucha más frecuencia debido a una radiación solar más intensa y a concentraciones más elevadas de gases precursores procedentes de emisiones biogénicas, dándose incluso en atmósferas contaminadas. Además, en este trabajo se describe la posibilidad de evaporación de partículas, que parece verse favorecida bajo condiciones de altas temperaturas, intensa radiación solar, baja humedad relativa y de dilución atmosférica.A detailed study of the physical and chemical processes and sources affecting atmospheric aerosols in Montseny in the Western Mediterranean regional background is presented in this work, a region relatively understudied in Europe in this field. Atmospheric aerosols in the context of air pollution is currently an area of study of great interest owing to the health implications of exposure to airborne contaminants and the effects of aerosols on global climate change. A long-term time series of data (2002-2010) of PM2.5 (particulate matter of diameter less than 2.5 µm) and chemical composition is analysed with the aim to identify the trends and fluctuations in concentrations, and the possible causes for such fluctuations are described. Trend analysis of PM2.5 shows a decreasing trend with statistical significance for levels of PM across Europe. This decreasing trend is attributed to the efficacy of pollution abatement strategies, as many components associated with anthropogenic activities undergo a gradual decrease such as sulphate, organic carbon and trace metals. Furthermore, large scale meteorology such as the North Atlantic Oscillation is also identified as an influencing process affecting PM concentrations across Europe. In certain countries the economic recession of recent years has appeared to further compound these decreasing trends in ambient pollutant levels. The emission sources of both PM1 (particulate matter of diameter less than 1 µm) and sub-micrometre particles are identified and the daily and seasonal variations in the emission sources are described. These sources include secondary sulphate, secondary organic aerosol, fuel oil combustion, traffic and biomass burning, industrial and nitrate. New particle formation and growth is identified as an important source of ultrafine particles (particles of diameter less than 100 nm). Many of these sources undergo a distinct daily and weekly variation and seasonal variation associated with anthropogenic activities and meteorology across the region, with elevated concentrations during the warmer months as a result of enhanced photochemistry, elevated concentrations of crustal material associated with soil resuspension and increased Saharan dust intrusions, elevated levels of sulphate and shipping emissions as a result of pronounced sea breezes, and enhanced biogenic emissions. Intense episodes of pollution are described during the colder months as a result of anticyclonic conditions causing air mass stagnation and the accumulation of pollutants across the region. These episodes are especially characterised by elevated concentrations of nitrate. Local meteorology, specifically the action of mountain and sea breezes, are identified as controlling agents for the transport of polluted air masses from urbanised areas to rural areas, and govern the daily variability of atmospheric aerosols. During the colder months, new particle formation is observed to occur in the absence of a polluted atmosphere, provided solar radiation and the necessary gaseous precursors (sulphuric acid, semi-volatile organic vapours) are available. However, during warmer months, new particle formation is observed to be much more frequent owing to the intensified solar radiation and increased concentrations of gaseous precursors from biogenic emissions, even in polluted atmospheres. This scenario has not been described in many publications for non-urban environments. Furthermore, the possibility of particle evaporation is described, suggesting that gas-to-particle transformations (homogenous nucleation) are reversible, and this process is significantly underreported in literature. Evaporation appears to be favoured under warm temperatures, high solar radiation, low relative humidity and atmospheric dilution.
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Sánchez, Balseca Joseph. "Spatio-temporal association of physic characteristics and chemical composition of the atmosphere with human mortality data." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673195.
Full textAbstract:
Air pollution is an environmental challenge that has an important influence on the life of human beings.
Therefore, the development, implementation, and evaluation of new statistical approaches will improve the numerical modeling of the spatial distribution of air pollutants and their socio-economic impact. Demography statistically evaluates the change in human populations over time (temporal models). Mortality is a factor that influences the human population, and its definition in the short, medium and long term is of utmost importance for government health and economic plans. Air pollution directly influences human mortality, and it should be incorporated into the structure of demographic mortality models. Air pollution data is collected from satellite information or ground-level monitoring, which needs statistical models to obtain pollution levels in places with no monitoring stations. Air pollution data description uses the aggregate form (mean values over a large geographical level) and the spatially-structured form (values at local territories). In addition, air pollution data could be statistically treated using both traditional and compositional approaches. This thesis assesses the addition of air pollution data using both forms of descriptions separately under both statistical treatment approaches on the useful demographic Farrington-Like model. For this purpose, a generalized linear modelling framework was proposed assuming that the human mortality data has a negative binomial distribution. The mortality data used both total and disaggregated forms. The disaggregation used three demographic aspects sex, age, and location. Air pollutants were modelled using Dynamic Linear Models (DLM) and spatially extended with Gaussian and Gaussian-Mattern Fields under traditional and compositional approaches. For instance, the spatial distribution of concentration of PM2.5 in wildfires event with a limited number of monitoring stations was featured with a Gaussian-Mattern Field; and the spatial distribution of concentrations of SO2, CO, O3, NO2, and PM2.5 was featured using a Gaussian Field. The results obtained in each stage of this doctoral thesis presented adequate quality-model indexes (NSE = 0.5, RMSE ˜0, and Pearson correlation coefficients ˜ 1)La contaminación del aire es un desafío ambiental que tiene una influencia en la vida de los seres humanos. Por lo tanto, el desarrollo, implementación y evaluación de nuevos enfoques estadísticos mejorará el modelado numérico de la distribución espacial de los contaminantes del aire y su impacto socioeconómico. En el ámbito de la demografía, es común evaluar estadísticamente el cambio en las poblaciones humanas a lo largo del tiempo (modelos temporales). La mortalidad es un factor que influye en la población humana, y su definición en el corto, mediano y largo plazo es de suma importancia para los planes de salud y económicos del gobierno. La contaminación del aire influye directamente en la mortalidad humana y debe incorporarse a la estructura de los modelos demográficos de mortalidad. Los datos de contaminación del aire se recopilan a partir de información satelital o monitoreo a nivel del suelo que necesita modelos estadísticos para obtener los niveles de contaminación en lugares sin estaciones. La descripción de los datos de contaminación del aire se realiza de forma agregada (valores medios en una gran escala geográfica) y de forma espacialmente estructurada (territorios locales). Además, los datos de contaminación del aire se tratan estadísticamente utilizando enfoques tanto tradicionales como de composición. Esta tesis evalúa la adición de datos de contaminación del aire utilizando ambas formas de descripciones por separado bajo ambos enfoques de tratamiento estadístico en el modelo demográfico Farrington-Like. Para este propósito, se propuso un marco de modelado lineal generalizado asumiendo que los datos de mortalidad humana tienen una distribución binomial negativa. Los datos de mortalidad se usaron como totales y desagregados. La desagregación utilizó tres aspectos demográficos: sexo, edad y ubicación. Los contaminantes del aire se modelaron utilizando modelos lineales dinámicos (DLM) y se ampliaron espacialmente con los campos Gaussiano-Mattern y Gaussiano bajo enfoques tradicionales y de composición. Por ejemplo, la distribución espacial de la concentración de PM2.5 en un evento de incendios forestales con un número limitado de estaciones de monitoreo se presentó con un campo Gaussian-Mattern; y la distribución espacial de las concentraciones de SO2, CO, O3, NO2 y PM2.5 se presentó utilizando un campo gaussiano. Los resultados obtenidos en cada etapa de esta tesis doctoral presentaron índices de calidad de modelado adecuados (NSE = 0,5, RMSE ≈0 y coeficientes de correlación de Pearson ≈1).
Enginyeria ambiental
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Heywood, Matthew Spencer. "Optical and Mass Spectrometric Studies of a Helium Dielectric-Barrier Atmospheric-Pressure Plasma Jet Used as an Ambient Desorption Ionization Source." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/2980.
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Recently there has been a surge in the field of mass spectrometry centered around the concept of rapid analysis of target analytes with minimal or no sample preparation. The target analyte undergoes desorption from its surface of origin and is subsequently ionized under ambient conditions. The technique is termed ambient desorption/ionization mass spectrometry (ADI-MS). Since the introduction of ADI-MS in 2004, there has been an explosion of research based around the development of novel ambient desorption/ionization (ADI) sources with the capability of desorbing and ionizing a variety of target analytes from various sampling surfaces. One type of ADI source uses the properties of an electrical discharge, typically a helium gas plasma, for desorption and ionization. For electrical-discharge-based sources, ionization is the result of an atmospheric pressure chemical ionization (APCI) process. The initiation of the APCI process it generally attributed to the Penning ionization of atmospheric nitrogen (N2) by highly energetic helium metastable species (Hem). In this work, I describe the direct imaging of the densities of helium metastable atoms in atmospheric pressure plasma jet (APPJ) of a helium-based dielectric-barrier discharge (DBD) using collisionally-assisted laser-induced fluorescence. Axial Hem distributions are compared to the emission of excited helium (He*) and nitrogen ion (N2+*) species in the plasma. A correlation is found between Hem densities and the performance of the ionization source in ADI-MS. Fluorescence images also show that Hem densities increase substantially when a glass slide is placed 10 mm from the discharge capillary in a geometry typical for desorption/ionization experiments. Advantage is taken of the time-varying nature of the plasma to produce axial profiles of temporally and spectrally resolved fluorescence images of Hem atoms and ground state nitrogen ions in the plasma jet. The axial distribution and similarities in the temporal behavior of the helium metastable and ground state nitrogen ion species give strong evidence that nitrogen ion species are created via Penning ionization by helium metastable atoms. Although axial distributions of He*,N2+*, and N2* emission support the fluorescence data, temporally-resolved emission measurements show that emission from key plasma species is almost entirely the result of excitation by a temporal energy wave. The effect that hydrogen (H2) has on the helium metastable atom densities is also presented. The addition of hydrogen to the discharge gas severely quenches the metastable state, leaving it virtually undetectable. The addition of 0.9% H2 to the helium in the source provides an order of magnitude increase in ADI-MS signal for target analytes despite the quenching of the Hem population.
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Bagulho, Mariana Polido de Oliveira. "As cores como estimulo ambiental : efeitos nas respostas do consumidor na restauração." Master's thesis, Instituto Superior de Economia e Gestão, 2015. http://hdl.handle.net/10400.5/10645.
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Mestrado em MarketingA atmosfera de serviços, durante muito tempo, não teve o reconhecimento que tem atualmente enquanto forte ferramenta de marketing. Alguns estudos têm vindo a demonstrar a influência da atmosfera e dos estímulos ambientais no consumidor a vários níveis. Este estudo pretende analisar o efeito de um estímulo em particular - as cores - no consumidor ao nível das emoções, perceções e comportamentos de aproximação na restauração. A metodologia utilizada foi a quantitativa e o propósito é exploratório, uma vez que se pretende explorar o efeito das cores da atmosfera no consumidor. Assim, foi recriado, em 3 dimensões, o interior de um restaurante em duas versões: numa usou-se uma cor quente (vermelho) e na outra uma cor fria (azul). As imagens do restaurante foram colocadas num questionário online, através do qual se recolheram 516 respostas. Os resultados permitiram observar que as cores influenciam o consumidor, em particular os estados de prazer, excitação, perceção do ambiente, perceção do nível de preços e intenção de consumir. À exceção da intenção de consumir, os inquiridos mostraram uma preferência pelo ambiente de cor quente. Em função dos resultados obtidos no estudo, as empresas devem reconhecer a importância da atmosfera, e das cores em específico, nas emoções, perceções e comportamentos de aproximação dos consumidores. E devem ainda ter em atenção a escolha das cores aquando do planeamento da atmosfera do serviço.
For a long time, services atmosphere was not recognized as a strong marketing tool as it happens nowadays. Some studies have been demonstrating that atmosphere and environmental stimuli's have an influence on consumers. This study intends to analyze the effect of a specific stimulus - colors - on consumer's emotions, perceptions and approach behaviors in restaurants. The methodology used in this study was quantitative. The purpose is exploratory since the intention is to explore the atmosphere's color effect on consumer's behavior. Therefore, it was recreated (in 3 dimensions) two versions of a restaurant's interior. For the first one was used a warm color (red) and a cool color (blue) on the second one. The two images were applied on an online survey which has collected 516 responses. The results observe that colors have an influence on consumers, especially on pleasure, arousal, environmental and price perceptions and purchase intention. Excluding purchase intention, respondents showed a preference for warm color environments. In conclusion, companies should recognize the importance of atmosphere and colors on emotions, perceptions and approach behaviors. Therefore, companies should chose colors carefully when it comes to service atmosphere planning.
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Whitson, Sara E. "The Development, Implementation and Application of Ambient Ionization Mass Spectrometry to Complex Polymeric Systems." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1226433768.
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Raeppel, Caroline. "Evaluation de la contamination des atmosphères intérieures et extérieures induite par les usages non agricoles de pesticides." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00869960.
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Dans le but d'évaluer la contamination des atmosphères intérieures et extérieures induite par les usages non agricoles de pesticides, deux approches complémentaires ont été mises en oeuvre : l'utilisation de capteurs passifs de type Tenax TA pour réaliser des prélèvements d'air, et l'utilisation de cheveux employés comme biomarqueurs d'exposition. Des campagnes de mesures ont été menées sur plusieurs sites à la suite de traitements de désherbage ou de désinsectisation ainsi quedans des logements. Les échantillons d'air et de cheveux ont été extraits respectivement par thermodésorption et par extraction solide-liquide, avant d'être analysés en chromatographie gazeuse couplée à la spectrométrie de masse (GC-MS). Une augmentation du niveau de contamination de l'air extérieur et intérieur et l'existence de transferts entre ces deux milieux ont pu être observées après l'application de pesticides. Dans les logements, des pesticides actuellement employés mais aussi des pesticides interdits et persistants ont été détectés. Plusieurs pesticides ont également été détectés dans les cheveux, mais l'exposition humaine à ces derniers n'a pas pu toujours être corrélée à une contamination de l'air.
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Kacem, Ahmed. "Modélisation numérique de la pyrolyse en atmosphères normalement oxygénée et sous-oxygénée." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4708/document.
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Le taux de pyrolyse est un paramètre clé du comportement du feu qui, à son tour, contrôle le transfert de chaleur à la surface du combustible. Dans cette étude, un modèle de pyrolyse volumique d’un combustible solide semi–transparent prenant en compte le rayonnement au sein du solide et la régression de l’interface a été couplé au code ISIS. Un algorithme génétique a été utilisé afin de déterminer un jeu optimal de paramètres cinétiques pour la pyrolyse du PMMA à partir d’une expérience de pyrolyse pure sous cône calorimètre en atmosphère normalement oxygénée. Des expériences de pyrolyse avec flamme de plaques carrées ont été réalisées afin de valider les résultats du modèle. L’analyse des résultats obtenus au centre de l’échantillon montre que la vitesse de régression de la surface devient constante en fonction du temps et que la contribution radiative au flux de chaleur total reste pratiquement constante. Les résultats du modèle couplé sont en bon accord avec la littérature et les mesures de cette étude. Néanmoins, le flux de chaleur incident aux bords de l’échantillon est sous-estimé. Une bonne concordance est obtenue entre les hauteurs de flammes prédites et celles déduites de la corrélation de Heskestad. Enfin, pour simuler la pyrolyse du PMMA en atmosphère sous–oxygénée, une chimie à deux étapes avec prise en compte du phénomène d’extinction de la flamme a été utilisée. Les résultats des simulations ont été comparés aux mesures réalisées dans le dispositif CADUCEE pour des fractions volumiques d’oxygène de 18,5% et 19,5%. La baisse du taux de pyrolyse et des températures de flamme avec la fraction volumique d’oxygène est bien reproduite par le modèleThe pyrolysis rate is a key parameter controlling fire behavior, which in turn drives the heat feedback from the flame to the fuel surface. In the present study an in–depth pyrolysis model of a semi–transparent solid fuel with spectrally–resolved radiation and a moving gas/solid interface was coupled with the CFD code ISIS. A combined genetic algorithm/pyrolysis model was used with Cone Calorimeter data from a pure pyrolysis experiment to estimate a unique set of kinetic parameters for PMMA pyrolysis. In order to validate the coupled model, ambient air flaming experiments were conducted on square slabs of PMMA. From measurements at the center of the slab, it was found that the experimental regression rate becomes almost constant with time, and that the radiative contribution to the total heat flux remains almost constant. Coupled model results show a fairly good agreement with the literature and with current measurements. Nevertheless, the flame heat flux feedback at the edges of the slab is underestimated. Predicted flame heights based on a threshold temperature criterion were found to be close to those deduced from the correlation of Heskestad. Finally, in order to predict the pyrolysis of PMMA under reduced ambient oxygen concentration, a two–step chemical reaction and a flammability diagram for flame extinction was used. Model results are compared with data obtained in the experimental facility CADUCEE for ambient oxygen concentrations of 18.2 and 19.5%. Data show that the total mass loss rate and flame temperature decrease with the oxygen concentration, which is well reproduced by the model
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Mainord, Jacinda L. "Investigation of Ambient Reactive Nitrogen Emissions Sources and Deposition in the Columbia River Gorge National Scenic Area." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3621.
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Anthropogenic reactive nitrogen is emitted into the atmosphere from fossil fuel combustion (nitrogen oxides) and agricultural activities (nitrogen oxides and ammonia). Nitrogen oxide emissions have long been controlled for their role in ambient air pollution and human health effects. However, reactive nitrogen deposition is less understood even though it can play a significant role in altering biodiversity, impairing ecosystem and biogeochemical function and degrading cultural artifacts. Although nitrogen deposition is a natural part of biogeochemical cycling, many ecosystems across the United States are at risk of exceeding the critical nitrogen deposition load. While nitrogen oxides are routinely measured in urban areas, far less is known in non-urban landscapes where ecosystems may be especially sensitive. Regional chemical transport models have been used to predict the impacts of ambient reactive nitrogen deposition in non-urban areas, but models have difficulty simulating reactive nitrogen due to poorly quantified emissions, especially from the agricultural sector.
My research explores the speciated deposition of reactive nitrogen through monitoring and modeling in the unique field setting of the 150 mile Columbia River Gorge (CRG) located along the border of Oregon and Washington. This site is ideally suited for this investigation due to the large sources of reactive nitrogen at either end of the CRG and unique seasonally driven channel wind flow. Seasonally driven wind allowed us to look at the reactive nitrogen emissions flowing through the CRG to assess ambient the reactive nitrogen partitioning and deposition gradient. Using data collected by the United States Forest Service to control ambient haze in the CRG and our co-located nitrogen oxides (NOx) gas analyzer, we first characterized the influence of seasonal, bimodal wind distributions on the spatial distribution of reactive nitrogen. We found that during winter months with predominantly easterly winds, particulate nitrate and ammonium and gas-phase nitrogen dioxide levels create a gradient from the eastern end to the western end. Particulate nitrate and sulfate mass concentrations influence the CRG gradient during summer months with predominantly western winds. We also found that the magnitude of the impact from east is greater than the magnitude of impact from the west. When we compared our observations to regional chemistry transport models, we found that models are significantly under-predicting levels of reactive nitrogen in the CRG. This bias is not isolated to a single station within the Gorge, but throughout the whole Columbia Basin. Our results indicate that there are under-represented emissions in the region leading to this bias.
Partly due to the bias in reactive N gas-phase species in the CRG, regional models have been underestimating the impact of gas-phase reactive N on dry N deposition. We conducted field studies at two sites within the CRG monitoring reactive nitrogen species (nitric oxide, nitrogen dioxide, ammonia, nitric acid, particulate nitrate, particulate ammonium, and particulate sulfate) as well as ozone and meteorological parameters. These measurements allowed us to conduct the first comprehensive analysis of reactive nitrogen partitioning and deposition in the CRG.
Through our measurements, we found reactive nitrogen was higher in the spring than the summer. We found concentrations ranging from 0-15 ppbv ammonia, 0-7 ppbv nitric acid, 0-2 µg/m3 ammonium nitrate and 0-1 µg/m3 ammonium sulfate at the sites. Through the measurements of all these species, we evaluated the limiting gas-phase precursor to inorganic nitrogen particle formation. In the springtime, ammonia limits the formation of particulate reactive nitrogen; while in the summer, nitric acid and oxidized sulfur limit the formation of inorganic nitrogen particles. This suggests that there may be more sources of ammonia in the spring with fertilizer application or perhaps reactive nitrogen reservoirs are renoxified through thermal dissociation during warmer summer months.
Our estimated deposition from gas and particle phase reactive nitrogen ranged from 0-0.14 kg N/ha per day. We also found that gas-phase reactive nitrogen plays the largest role in dry N deposition in the CRG with particle-phase contributing less than 15% of total dry N deposition. These results are important for land managers to understand the total impact of reactive nitrogen to non-urban areas. This research can inform mitigation strategies for haze formation, identify the major species and sources involved in dry N deposition and assess the potential impacts to ecosystems and cultural artifacts.
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Mader, Brian T. "Gas/solid and gas/particle partitioning of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polycyclic aromatic hydrocarbons to filter surfaces and ambient atmospheric particulate material /." Full text open access at:, 2000. http://content.ohsu.edu/u?/etd,193.
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Tsurumaru, Hiroshi. "Comprehensive evaluation of oxidative capacity of ambient air with new detection technique of HOx (OH, HO{2}) radical production rate." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/195990.
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Izquierdo, Miguel Rebeca. "Source areas and atmospheric transport processes of chemical compounds and pollen in the NE Iberian Peninsula and the Canary Islands." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/96858.
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Els ecosistemes forestals reben una entrada important de nutrients per deposició atmosfèrica. Per conèixer millor els mecanismes de deposició s'han realitzat mesures en paral·lel de la deposició humida, seca i global en una estació de mostreig al Montseny. La comparació entre els fluxos humit i sec va revelar que els compostos atmosfèrics en aquesta zona es dipositen principalment via deposició humida (74% de deposició humida+seca). Els nostres resultats indiquen que la deposició global representa bé la deposició atmosfèrica total, ja que la deposició global més les partícules dipositades després de l'última pluja van representar el 97% de la deposició total (humida+seca).
Els models de canvi climàtic per a la regió Mediterrània prediuen modificacions en els patrons de circulació de vent i de precipitació. La caracterització de la climatologia sinòptica i el transport a llarga distància de contaminants atmosfèrics al Montseny va mostrar una disminució de les adveccions atlàntiques i un augment de les masses d'aire africanes i europees en la circulació general en del NE d'Espanya. S'han aplicat Mètodes d'Anàlisi Estadístic de Trajectòries (TSMs) per interpretar els canvis de la química de la precipitació durant els últims 25 anys en alguns ions que mostren tendències significatives (ex. SO42-, H+ i NO3-). En el període inicial (1984-1993) els contaminants antropogènics (SO42-, H+ i NO3-) que es dipositaven al Montseny procedien principalment d’Europa Central i Oriental. La disminució significativa de SO42- i H+ a la precipitació del Montseny reflecteix la reducció de les emissions de sofre al centre d'Europa. En el període recent (1998-2009), els TSMs indiquen que l’origen del SO42-, H+ i NO3- es pot atribuir al tràfic marítim en el Mar del Nord i a països de l’Est d'Europa i el Nord d'Àfrica. Cal tenir això en compte per a la protecció dels ecosistemes i la salut humana.
La pols mineral és un aerosol atmosfèric d'origen natural que presenta una entrada en polsos irregulars i massius a l'atmosfera que pot produir nombrosos impactes ambientals. En aquest context, s'ha descobert que els elements derivats de la pols mineral influeixen en els ecosistemes terrestres i marins del NE d’Espanya. Cal tenir en compte que la pols actua com a substrat on reaccionen els contaminants antropogènics, per tant, no s’ha de considerar com a font natural pura. Al Montseny, la pols africana va aportar el 66% dels 576μmols m-2 a-1 de fòsfor (P) particulat total dipositat. Assumint que les mostres recollides a 25km de la costa són representatives de l'entrada P atmosfèric a les aigües costaneres, el P atmosfèric soluble representa <1% de la producció primària nova anual de la Mediterrània Occidental. Tot i això, un únic episodi de pols africana (22-27 maig, 2008) va representar el 24-33% de la producció nova anual induïda pel P atmosfèric. Aquests resultats destaquen la importància biogeoquímica dels aerosols dipositats a la mar Mediterrània Occidental.
El transport a llarga distància de pol·len s'ha estudiat a Tenerife (Illes Canàries). Les principals procedències van ser: (1) La regió Mediterrània a través dels vents alisis en la capa límit marina (MBL). Aquests episodis es van caracteritzar per la presència de pol·len d'arbres (Casuarina, Olea i Quercus) barrejat amb pol·len d'herbes (Artemisia, Chenopodiaceae-Amaranthaceae i Poaceae). (2) El sector del Sàhara, a través del transport de pol·len principalment d'herbes (Chenopodiaceae-Amaranthaceae, Cyperaceae i Poaceae) a nivell de la MBL i, en un cas, el pol·len de Casuarina en la troposfera lliure. I (3) la regió del Sahel, amb episodis associats al transport de pol·len de palmeres (Arecaceae) i herbes (Chenopodiaceae-Amaranthaceae, Cyperaceae i Poaceae). Cal tenir en compte aquests episodis a Tenerife com a possible causa dels episodis d'al·lèrgia respiratòria.Forest ecosystems receive an important input of nutrients from the atmosphere. To better understand the mechanisms of deposition measurements in parallel of wet, dry and bulk deposition have been performed. The comparison between wet and dry fluxes revealed that the removal of atmospheric compounds at Montseny occurred mainly by wet deposition, which accounted for 74% of total deposition (wet+dry). Bulk deposition at Montseny was considered representative of total atmospheric deposition, since bulk deposition plus the recovery of deposited particles after the last rain accounted for 97% of total deposition (wet+dry). Climate change models predict modifications in the wind circulation and precipitation patterns for the Mediterranean region. Our study on the characterisation of the synoptic climatology for the last 25 years showed a decrease of Atlantic advections and the increase of African and European air flows in the general circulation over NE Spain. Trajectory Statistical analysis Methods (TSMs) have been used to interpret the variation of precipitation chemistry during the last 25 years for some ions that show significant variation trends (e.g. SO42-, H+ and NO3-). A source-receptor model indicates that in the initial period (1984-1993) anthropogenic pollutants (SO42-, H+ and NO3-) deposited at Montseny originated from central and eastern Europe. The significant temporal decrease of SO42- and H+ in precipitation collected in Montseny reflects the abatement of sulphur emissions in central Europe. In the recent period (1998-2009), the model indicates that the sources of SO42-, H+ and NO3- can be attributed to maritime traffic in the North Sea and from countries in Eastern Europe and North Africa. This must be taken into account for a further protection of ecosystems and human health. Mineral dust is an atmospheric aerosol from natural origin which, entrained massively into the atmosphere, can have significant environmental impacts. In this context, mineral dust-derived element fluxes have been found to influence terrestrial and marine ecosystems of the eastern Iberian Peninsula. Dust is considered as a “natural” pollutant, but it should be noted that it acts as a substrate for reaction of anthropogenic pollutants. Therefore dust can not be considered a pure natural source. In Montseny, African dust accounted for 66% of the 576 µmols m-2 y-1 of total particulate phosphorus (P) deposited. Samples (collected 25 km inland from the coast) were assumed to represent the atmospheric P input into coastal waters. Based on this assumption, the atmospheric-derived soluble P contributed only <1% of annual new primary production in the western Mediterranean. However, one strong African dust event (22-27 May, 2008) accounted for 24-33% of the atmospheric P-induced annual new production. These results highlight the biogeochemical importance of aerosols deposited in the Western Mediterranean Sea. The long-range transport of pollen was studied in Tenerife (Canary Islands). The main were: (1) The Mediterranean region through the trade winds in the marine boundary layer (MBL). These episodes were characterized by the presence of pollen from trees (Casuarina, Olea and Quercus) mixed with pollen from herbs (Artemisia, Chenopodiaceae-Amaranthacea and Poaceae). (2) The Saharan sector, through transport at the MBL level carrying principally pollen from herbs (Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae) and, in one case, Casuarina pollen uplifted to the free troposphere. And (3) the Sahel, which appears as episodes associated to transport of pollen from palm trees (Arecaceae) and herbs (Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae). Sporadic events of long-range pollen transport need to be taken into consideration in Tenerife as possible cause of respiratory allergy episodes.
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Pereira, Daniela Cristina de Almeida. "Poluição em ambientes internos. Caracterização de espécies no material particulado de atmosferas escolares." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-12042018-094059/.
Full textAbstract:
Atualmente a poluição do ar é um assunto relevante para a população e para os órgãos governamentais, em razão dos efeitos na saúde e no clima. Tão importante quanto a quantidade de material particulado na atmosfera, é também, a sua composição. O objetivo deste estudo foi determinar a concentração de MP10 e espécies orgânicas e inorgânicas em amostras coletadas em ambientes internos e externos de três escolas do Estado de São Paulo, para avaliar a qualidade do ar. As concentrações de MP10 foram determinadas por gravimetria, depois foram submetidas à extração, rotaevaporação, fracionamento em coluna, e os compostos foram determinados através da cromatografia gasosa acoplada ao espectrômetro de massas; o carbono elementar e o carbono orgânico foram determinados pelo método termo-óptico, pelo sistema desenvolvido na Universidade de Aveiro; o carbono grafítico foi determinado por refletometria e os metais por EDXRF e algumas amostras foram analisadas por cromatografia de íons, no instituto de Astronomia, Geofísica e Ciências Atmosféricas da Universidade de São Paulo. As amostras de MP10 foram coletadas nos seguintes sítios: (i) escola de Aplicação, dentro da Cidade Universitária, de área urbana que sofre influência de via de grande movimento de veículos e da vegetação local; (ii) escola Madalena de Almeida do Cais, na cidade de Nova Granada localizada a cerca de 475 quilômetros da cidade de São Paulo, com baixa população e poucos veículos; (iii) escola particular em bairro residencial da zona oeste, que sofre a influência de avenida com grande fluxo de veículos. Os resultados indicaram que a concentração do MP10 foi mais alta em ambiente interno que externo na escola dentro da USP. Na escola particular, a concentração mediana apontou que o ambiente externo apresentou concentração de MP10 superior ao ambiente interno. Para os hidrocarbonetos policíclicos aromáticos, observou-se que tanto na escola do interior quanto na escola do campus, houve maior concentração em ambiente interno, e alguns de maior peso molecular, atribuídos às emissões veiculares, foram mais altos em ambiente externo. As razões diagnósticas indicaram queima de combustíveis fósseis ao redor dos sítios amostrados. As amostras coletadas nas escolas apresentaram baixos riscos à saúde. Os compostos 2- metilantraquinona e benzo(a)antraceno-7,12-diona foram encontrados nas amostras, denotando a influência da exaustão veicular. A fração carbonácea (EC + OC) apresentou maior concentração em ambiente externo, e a razão OC/EC para o ambiente externo apontou para a queima de biomassa. A fonte de carbono grafítico corroborou a influência do tráfego. Para a maioria dos elementos, com exceção do cromo, manganês e ferro, as concentrações obtidas em ambiente interno foram as mais altas, majoritariamente oriundos da ressuspensão do solo. O cromo e o manganês estão relacionados com a emissão dos veículos que utilizaram a mistura gasolina e etanol; o ferro, com a crosta terrestre. Para os íons, a concentração média para ambientes externos apresentou a seguinte tendência: SO42- > NO3- > Ca2+ > NH4+ > Na+ > K+> Mg2+ > Cl- e para ambientes internos foi Ca2+ > SO42- > NO3- > Na+ > NH4+ > K+ > Cl- > Mg2+ > F-. A maioria das espécies apresentou a influência da ressuspensão do solo; o nitrato e o sulfato foram atribuídos à emissão veicular, e o cátion amônio foi formado por reações a partir da degradação da matéria orgânica e dos processos que ocorrem nos catalisadores veiculares.Nowadays, air pollution is a relevant issue for people and government agencies because of the health and climate effects. As important as the amount of particulate matter in the atmosphere, is also, its composition. The object of this study was to determine the concentration of PM10 and organic and inorganic species in samples collected in indoor and outdoor environment of three schools in the State of São Paulo, to evaluate air quality. The concentrations of PM10 were determined by gravimetry, then the samples were subjected to extraction, rotary evaporation, column fractionation, and the compounds were determined by gas chromatography coupled to the mass spectrometer; elemental carbon and organic carbon were determined by the thermooptical method, by the system developed at the University of Aveiro; the graphitic carbon was determined by reflectometry and the metals by EDXRF and some samples were analyzed by ion chromatography, at the Institute of Astronomy, Geophysics and Atmospheric Sciences of the University of São Paulo. PM10 samples were collected at the following sites: (i) school of Application, within the University City, an urban area that is influenced by a large vehicular route and local vegetation; (ii) Madalena de Almeida do Cais school, in the city of Nova Granada located about 475 kilometers from the city of São Paulo, with low population and few vehicles; (iii) private school in a residential neighborhood in the western zone, which suffers the influence of avenue with a large flow of vehicles. The results indicated that PM10 concentration was higher in indoor than outdoor environment in the school within USP. In the private school, the median concentration indicated that the outdoor environment presented a concentration of PM10 higher than the indoor environment. For the polycyclic aromatic hydrocarbons, it was observed that both countryside school and campus school, a higher concentration of compounds in the indoor environment was found, only some high molecular weight compounds, attributed to vehicular emissions, were higher in the external environment. Diagnostic ratios indicated the burning of fossil fuels around the sites sampled. Samples collected in schools presented low health risks. 2-methylanthraquinone and benzo(a)anthracene-7,12-dione were found in the samples, denoting the influence of vehicle exhaust. The carbonaceous fraction (EC + OC) presented higher concentration in the outdoor environment and OC/EC ratio for the outdoor environment pointed to biomass burning. The graphite carbon source corroborated the traffic influence. For most of the elements, except for chromium, manganese and iron, the concentrations obtained in indoor environment were the highest, mainly derived from soil resuspension. Chromium and manganese are related to the emission of the vehicles that used the mixture gasoline and ethanol; iron is from the terrestrial crust. For the ions, the average concentration for outdoor environments presented the following trend: SO42-> NO3-> Na+> NH4+> Na+> K+> Mg2+> Cl- and for indoor environments was Ca2+> SO42-> NO3-> Na+ > NH4+> K+ > Cl-> Mg2+> F-. Most of the species showed the influence of soil resuspension; nitrate and sulfate were attributed to human activities, i. e., vehicular emission, and, the ammonium cation was formed by reactions from the degradation of the organic matter and the processes that occur in vehicular catalysts.