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 22 for “"hygroscopicity"”.
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Arctic Aerosol Sources and Continental Organic Aerosol Hygroscopicity
… issue: the sources of Arctic aerosol and the hygroscopicity of continental organic aerosol. Small particles were observed in Baffin Bay during September 2008 that coincided with high atmospheric and ocean surface dimethyl sulphide (DMS) concentrations suggesting that the aerosol formed from …
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Cloud condensation nuclei in western Colorado: observations and model predictions
… in time, and little in space. Estimates of the hygroscopicity parameter indicated consistently low aerosol hygroscopicity typical of organic aerosol species. The modeling approach included the addition of prognostic CCN to the Regional Atmospheric Modeling System (RAMS). The RAMS droplet …
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Hygroscopic growth and cloud condensation nuclei activity of fresh and chemically-aged biomass-pyrolyzed organic aerosol
… κ-Köhler theory to calculate representative hygroscopicity parameters, κGF and κCCN, respectively (c.f. Petters and Kreidenweis 2007). Discrepancies as large as factors of three between κGF and κCCN suggest that approximating the surface tension of solution droplets to that of pure water, as …
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Simultaneous collection of sulfur dioxide and nitrogen oxides via spray drying: Using sodium-based and calcium-based sorbents with select additives
… the removal-efficiency tests. The experimental hygroscopicity tests evaluated the dependence of optical particle diameter on relative humidity, additive concentration, additive composition, and sorbent composition. The solubility calculations evaluated the dependence of sorbent's solubility on …
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Aerosol Optical Properties and the Influence of Particulate Organic Matter
… results in a reduction in the aerosol's optical hygroscopicity. (Abstract shortened by UMI.).
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Isolation of ambient aerosols of known critical supersaturation: the differential critical supersaturation separator (DSCS)
… aerosol size distributions and size-resolved hygroscopicity of DScS separated aerosol. The dry diameter (Dp*) of particles sampled in the TDMA system as well as the known Sc prescribed in the DScS were combined in a modified version of K????hler Theory to make predictions of particle …
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Modeling study of the hygroscopic, optical, and cloud-activation properties of aerosols from biofuel combustion
… on the size distribution, mixing state, hygroscopicity, optical properties, CCN activity, and total quantity of aerosols emitted from biofuel combustion. The change in cloud characteristics due to biofuel burning aerosols is uncertain, in part, due to the uncertainty in the added number …
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Idealized particle-resolved large-eddy simulations to evaluate the impact of emissions spatial heterogeneity on CCN activity
… to aerosol-cloud interactions including particle hygroscopicity and cloud condensation nuclei (CCN) activity. This thesis investigates the impact of emissions spatial heterogeneity on CCN activity by using the particle-resolved model PartMC coupled to the Weather Research and Forecasting model …
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Design of oral insulin tablet formulations to enable manufacture and storage under ambient conditions
… chemical protection, whereas PVPVA offered lower hygroscopicity and greater resistance to humidity-induced plasticisation. These findings were extended to ternary insulin–sucrose–polymer systems. Optimisation via mixture design of experiments targeted elevated glass transition temperature (Tg) and …
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Orb weaver capture thread biomechanics and evolution
… glycoprotein core and aqueous layer that confers hygroscopicity. The first study investigates the durability of these droplets to cycling, or repeatedly adhering, extending, and pulling off. Droplets of four species proved resilient, cycling 40 times. Cycling, coupled with droplet humidity …
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Molecular interactions in pharmaceutical preformulation and supramolecular complexes. Structural properties governing drug-plasma protein binding and investigation of amino acids co-crystals
… drug (NSAID) and citric acid which overcome the hygroscopicity problems and improved the physical stability issues during storage. This study has also identified a new formulation which is helpful for improvement in the stability of effervescent tablets at various relative humidity (RH) …
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Sub-grid process analysis of the sensitivity of black carbon aging to particle microphysical properties at emission
… population, such as geometric mean diameter, hygroscopicity, and cloud condensation nuclei activity, to changes in local ambient conditions. The simulation results indicate that the evolution of the black carbon mixing state is most sensitive to the formation of secondary inorganic aerosol, …
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Role of Water in the Formation, Transformation and Fate of Secondary Organic Aerosol
… that there is a simple relationship between the hygroscopicity of organic aerosol and its oxygen-to-carbon ratio. Addition of various types of organic material onto sulfate particles resulted in the suppression of water uptake during droplet growth. Experiments using sulfate particles with …
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Development and implementation of a microresonator impactor for atmospheric particulate sensing
… studies introduced possible extensions to hygroscopicity and compositional applications. Ambient particle measurements with the MIS, simulating a real-world application to air quality monitoring, showed the capabilities as a PM instrument while highlighting concerns to be addressed for …
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Investigating Aerosol Composition with Low Cost Optical Particle Counters
… This provides information on the volatility and hygroscopicity of the aerosols. These OPC outputs are processed programmatically and fed into a neural net to classify what category an incoming aerosol belongs to. This method is run for both compound-derived categories which mimic real PM sources …
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Cloud condensation nucleus activity comparison of dry- and wet-generated mineral dust aerosol : the significance of soluble material
… However, the former requires a single hygroscopicity parameter instead of the two adjustable parameters required by the latter. For dry-generated particles, the size dependence of K is likely an artifact of the shape of the size distribution: there is a sharp drop-off in particle …
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Synthetic Design of Multiphase Systems for Advanced Polymeric Materials
… and demonstrated over 50,000% increased hygroscopicity relative to the parent homopolymer, and exhibited preserved crystallizability. Multiphase systems were also designed to additively manufacture reinforced elastomers through vat photopolymerization using a degradable scaffold approach …
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Analysis of drug polymorphism by diffuse reflectance visible spectroscopy- a novel approach
… polymorphs were further examined using hygroscopicity studies, contact angle measurements and computer simulation. The contact angles of several liquids with the polymorph surface were measured in order to characterise the nature of the functional groups exposed on the surface of the …
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Cellulose nanocrystals as a candidate for solar geoengineering
… brightening due to possessing only a moderate hygroscopicity, CNCs are promising for stratospheric aerosol injection. Desirable properties for agents of stratospheric aerosol injection include an ability to scatter incident shortwave solar radiation from space and a low propensity to absorb …
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Surfactant Behavior in Atmospheric Aerosols
… in the atmosphere might not always increase the hygroscopicity of aerosols. Overall, the results of this thesis demonstrate how variable aerosol properties are due to the organics present within complex aerosol compositions. This work will help direct future laboratory studies on atmospherically …
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