Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 53 for “"atmospheric aerosols"”.
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Surfactant Behavior in Atmospheric Aerosols
Atmospheric aerosols are very important in the Earth climate system due to their role in cloud formation and the global radiation budget. However, there are still many unanswered questions about how the composition of the aerosol varies and how this composition affects the climate system. While …
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Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations
… aim of this research is to assess the role of atmospheric aerosol and dust in the transport of metal and metalloid contaminants from mining operations to assess the deleterious impacts of these emissions to ecology and human health. In a field campaign, ambient particulates from five mining …
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Microphysics of atmospheric aerosols : phase transitions and cloud formation mechanisms
… uncertainties in understanding the effect of atmospheric aerosols on the environment. Using laboratory measurements, microphysical properties of typical micro-meter size atmospheric aerosols are investigated in this study. Upper tropospheric ice clouds (cirrus) form when ice is nucleated …
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Investigating secondary atmospheric aerosols using chemically-speciated observations and targeted model development
… uncertainties associated in simulating their atmospheric formation and fates, earth science models have historically struggled to accurately represent secondary aerosols, and continue to demonstrate significant bias when compared to observational datasets. The goal of this doctoral thesis is …
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The role of atmospheric aerosols on the development of the Southeast Madagascar phytoplankton bloom
Στον ολιγοτροφικό νότιο Ινδικό Ωκεανό, νοτιοανατολικά των ακτών της Μαδαγασκάρης, έχει παρατηρηθεί μια επαναλαμβανόμενη, σποραδική άνθηση (bloom) φυτοπλαγκτού, η οποία εμφανίζει έντονη ετήσια μεταβλητότητα. Η φυτοπλαγκτονική άνθηση Νοτιοανατολικά της Μαδαγασκάρης είναι συντονισμένη με το καλοκαίρι …
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Method for investigating the hygroscopic and optical character of organic carbon in atmospheric aerosols
… and optical characteristics of organic carbon aerosols impact the radiative energy balance of the atmosphere, and therefore Earth’s climate. This thesis discusses the development of a method to fractionate organic carbon according to climate-relevant properties. Ion-exchange High Performance …
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Inorganic and organic speciation of atmospheric aerosols by ion chromatography and aerosol chemical mass closure
… ionic constituents by ion chromatography (IC) in atmospheric aerosol samples; (2) to determine low molecular weight dicarboxylic acids (DCAs) and methanesulphonate (MSA-) by IC and to assess their contribution to the water-soluble organic carbon (WSOC); (3) to perform quality control of the IC …
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A framework for the modeling of suspended multicomponent particulate systems with applications to atmospheric aerosols
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1995.
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Investigations of cloud altering effects of atmospheric aerosols using a new mixed Eulerian-Lagrangian aerosol model
… altered the composition and size-distribution of atmospheric aerosol particles over the last century. This, in turn, has altered cloud albedo, lifetime, and patterns which together are thought to exert a negative radiative forcing on the climate; these are the indirect effects of atmospheric …
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Improving Our Understanding of Atmospheric Aerosols and Their Climate Effects: Implications for Satellite Retrievals and GCM Simulations
… focusing on improving our understanding of atmospheric aerosols using both observational data and model simulations. EOF analysis of Aerosol Index (AI) product from Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) reveals global distribution of absorbing …
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Characterisation of Microphysical and Optical Properties of Atmospheric Aerosols in a High Arctic environment: Villum Research Station, NE Greenland
Atmospheric aerosols are solid or liquid phase particles which are suspended in ambient air. These particles have an impact on the climate through direct and indirect radiative forcing, and their measurement presents challenges in high latitude environments where concentrations may fall under the …
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Physico-chemical characterisation of atmospheric aerosols in Tanzania, with emphasis on the carbonaceous aerosol components and on chemical mass closure
Three aerosol sampling campaigns were conducted at two sites (i.e., Dar es Salaam and Morogoro) in Tanzania, during different seasons from May 2005 through May 2006. A Gent PM10 stacked filter unit sampler with sequential Nuclepore polycarbonate filters, providing coarse (2-10 µm diameter) and fine …
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A new technique to find both real and imaginary index of refraction of atmospheric aerosols from clear sky radiance measurements.
… the real and imaginary index of refraction of atmospheric aerosols has been developed which utilizes polarized sky radiance measurements in the solar principal plane. The technique requires that the aerosol size distribution, Rayleigh optical depth, aerosol optical depth, surface albedo, and …
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Characterization of a 3D printed pumped counterflow virtual impactor and an aerodynamic lens concentrator
Atmospheric aerosols have an important role in cloud formation and, by extension, in the overall climate system. Field studies are required to refine the uncertainty associated with the net radiative effect of atmospheric aerosols. Two pre-existing cloud sampling devices, the pumped counterflow …
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Physical and chemical characterization of single atmospheric aerosols: Laboratory studies of interactions of acidic trace gases with sea -salt aerosols, and, Development efforts for an aerosol charging system using a corona discharge
… been an interest for in situ analysis of single atmospheric aerosols. To this end, the Flytrap instrument was developed under a NASA Phase I and Phase II Small Business Innovative Research Grant. The centerpiece of the instrument was a spherical void electrodynamic levitator that was used to …
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Development of improved sampling and analysis methods for measuring organic, elemental, and water-soluble organic carbon in atmospheric aerosols and application to aerosol studies in Europe and tropical/equatorial and oceanic regions
… improved collection procedures for carbonaceous aerosols, whereby the sampling artifacts are better controlled or can be corrected for; (3) to perform detailed carbonaceous aerosol characterisation studies in Belgium and at urban and forested sites throughout Europe and (4) in the Brazilian …
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A photophonic instrument concept to measure atmospheric aerosol absorption
… to measure the absorption of solar radiation by atmospheric aerosols was designed, built and tested. The concept was based on the photophonic phenomenon discovered by Bell and an acoustic resonator developed by Helmholtz. The design consisted of two chambers: an aerosol chamber and a reference …
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Atmospheric organic aerosol - water interactions
Atmospheric aerosols are responsible for adverse health effects and uncertain climate forcing. Depending on their composition, they can directly affect climate by scattering or absorbing solar radiation and they can also indirectly affect by serving as cloud condensation nuclei (CCN). While the …
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Ambient Observations of Aerosols, Novel Aerosol Structures, And Their Engineering Applications
The role of atmospheric aerosols remains a crucial issue in understanding and mitigating climate change in our world today. These particles influence the Earth by altering the Earth's delicate radiation balance, human health, and visibility. In particular, black carbon particulate matter remains …
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Characterization of microparticle velocities in converging-diverging nozzle systems
… speeds and scientific literature suggests that atmospheric aerosols may cause damage to them. Ongoing work in particle impact damage modeling, aerosol deposition methods, and fundamental studies of particle impact dynamics require acceleration of particles to high speeds and associated …
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