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 12 of 12 for “"Chemical Aging"”.
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Physical, Mechanical and Chemical Aging of Polyurea Nanocomposites
… addition on the overall character (mechanical, chemical and microstructural) of different polyurea systems. Control tensile strength, dynamic mechanical and nanoindentation properties of these composites are used as parameters to rank the mechanical performance of these composites. Evaluation of …
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Comparative Study of the Effects of Physical and Chemical Aging on Extracted and Recovered Asphalt Binders from Some Municipal and Provincial Roads in Canada
… comparatively study the effects of physical and chemical aging on the performance of extracted and recovered loose-mix and core mix samples from some provincial and municipal contracts in Ontario. In this study, four loose-mix (plant-aged) and eight core-mix (field-aged, 4 - 5 years) samples were …
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On Thermal Aging Prevention in Polymer Core Composite Conductor Rods
… to understand and reduce the impact of thermal aging on the core rods. The research demonstrates that the source of flexural failure in the rods moves from predominantly physical aging to predominantly chemical aging as a function of time and temperature, a brand new explanation that is …
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Hygroscopic growth and cloud condensation nuclei activity of fresh and chemically-aged biomass-pyrolyzed organic aerosol
… of the complexities in their initial size and chemical composition, but also because of transformations (aging) they undergo in the atmosphere upon exposure to reactive species (e.g., NH3 and O3). This study presents results of bench-scale experiments on biomass pyrolysis organic carbon (OC) …
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The effect of environmental aging/exposure on the durability of high performance polymeric composites
… been known to undergo both physical as well as chemical aging. The aging time, temperature, and environment play a significant role in affecting the physical and chemical aging behavior in the polymers. Currently, there is a dearth of information on the combined effects of physical and chemical …
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Manufacture and rehabilitation of guard-rail posts using composites for superior performance
… posts were subjected to 6-cycle accelerated aging and freeze-thaw chemical aging (in acidic, alkaline, water and salt water solutions). The retention in mechanical properties was measured using flexure tests and DMTA. The performance in terms of modulus and rigidity was reduced the most by …
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Examination of the Aging Properties of Novel Cyanate Ester Thermosets and the Subsequent Evaluation of the Material under Application Conditions
… for determining the effect of physical and chemical aging on these mechanical properties, and 3) evaluate the AroCy® B-10 cyanate ester resin from Ciba-Geigy for use in applications where temperatures could easily reach 177°C (300°F). Dynamic mechanical analysis used in a step isothermal …
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Investigation of the evolution of atmospheric particles with integration of the stochastic particle-resolved model PartMC-MOSAIC and atmospheric measurements
… the mixing state and other physico-chemical properties of individual aerosol particles can be tracked as the particles undergo aerosol aging processes. However, existing PartMC-MOSAIC applications have mainly been based on idealized scenarios, and a link to real atmospheric …
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Role of Water in the Formation, Transformation and Fate of Secondary Organic Aerosol
… explores the role of water in SOA formation, chemical aging and fate as cloud condensation nuclei. The formation of SOA from the photooxidation of isoprene in the presence of various sulfate seed particles was investigated using a flow tube reactor. Under constant environmental conditions, …
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Chemical and Physical Studies of Secondary Organic Aerosol Formed from Beta-pinene Photooxidation
… However, our understanding of the physical and chemical properties of these aerosols is inadequate, thus their climate and health influences are poorly constrained. In this study, we investigated the secondary organic aerosol (SOA) formation from OH-initiated oxidation of -pinene. The majority …
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Spinal cord gene expression changes in the chicken (Gallus gallus) model of phenyl saligenin phosphate induced delayed neurotoxicity
… that neuropathic OP esters have to bind NTE and chemically ?age? for OPIDN induction. It was hypothesized that phenyl saligenin phosphate (PSP), a neuropathic OP ester that essentially irreversibly inhibits NTE as it undergoes the chemical aging process, results in changes in spinal cord gene …
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Durability of Polyimide Adhesives and Their Bonded Joints for High Temperature Applications
… up to 18 months (including several intermediate aging times) in the above environments. The strain energy release rate (G) of the adhesive joints was monitored as a function of exposure time in the different environments. A 40% drop in fracture toughness was noted over the 18 month period, with …