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 31 for “"accelerated ageing"”.
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Investigation of accelerated ageing protocols applied to Lean NOx Trap catalysts
… results of my research work on the effects of ageing on the structure and functionalities of a tri-metal (Pt-Pd-Rh) commercial Lean NOX Trap (LNT) catalyst. The investigation has been focused on the correlation between the real-world ageing and artificial or rapid-ageing procedures. Samples …
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The effect of accelerated ageing on the corrosion resistance of sheet duralumin
Thesis: B.S., Massachusetts Institute of Technology, Department of Electrochemical Engineering, 1935
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The role of accelerated ageing in aberrant lung tissue repair and remodelling in COPD
… the pathogenesis of COPD are urgently needed. Accelerated ageing has been postulated to play a role in COPD with characteristic of ageing demonstrated in lungs from COPD patients compared to age-matched smokers without COPD. Recently, extracellular matrix (ECM) dysregulation has been described …
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Automated techniques for surface coating deterioration studies
… development of automated techniques for use in accelerated ageing studies involving polymer based surface coatings. These techniques were required in order that the effects of low concentrations of pollutant gases, specifically nitric oxide, on surface coatings could be investigated with a …
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The Convergence of Accelerated and Physiological Vascular Ageing: A Multi-Omic Analysis of 2D and 3D in vitro models of Progeria
Cellular and molecular hallmarks of ageing contribute heavily to onset of vascular disease with age. With the average age of global populations increasing, the associated rise in vascular diseases presents a huge challenge. A key obstacle in vascular gerontology research is a lack of suitable in …
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Analytical studies of the degradation of cellulose nitrate artefacts
… this. Work has also involved the use of accelerated ageing tests to study the effect of sulphate in the degradation and also the influence of inorganic fillers, iron and humidity. It has been concluded that the degradation of cellulose nitrate artefacts is dependent on the presence of …
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Nanostructured carbon-based materials for electrochemical applications
… the textural properties of the carbon products. Accelerated ageing tests on platinized samples prepared with mesoporous carbons exposed to different annealing treatments showed a significant improvement in stability after annealing for two hours at 1500oC, over performing an in-house prepared Pt/ …
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Glutathione Dynamics in Arabidopsis Seed Development and Germination
… microscopy. Stress in the form of natural and accelerated ageing, and germination at high and low temperature and at low water potential was applied to both WT and anGR2 seeds to test vigor. Results show similar glutathione levels and GR activity (except during late imbibition) in WT and anGR2. …
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The effect of carbon dioxide, temperature and water stress on growth, yield and seed quality of sunflower (Helianthus Annuus L.)
… hulled seed weight, seed germination and vigour (accelerated ageing and electrical conductivity tests). The results from conviron trials revealed that elevated CO2 enhanced growth by increasing the sunflower height in both trials. In terms of yield and seed quality of the progeny seeds, the trials …
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Impulse ageing of polymeric materials
… hypothesis that lightning impulses can lead to accelerated ageing of extruded polymeric cables. The results show that there may well be a reduction in electric field strength of the insulation of a power cable that experiences a lot of impressed lightning impulse over-voltages. Pre-designed …
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The Influence of Fibre Processing and Treatments on Hemp Fibre/Epoxy and Hemp Fibre/PLA Composites
… compared to the UTFE composites. Hygrothermal ageing of 65 wt% untreated and alkali treated long and short fibre/epoxy composites (produced by curing at 70oC) showed that long fibre/epoxy composites were more resistant than short fibre/epoxy composites and ATFE composites were more resistant …
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Effect of Harvest date on seed quality and potential longevity of two Soyabeans(Glycine max(L.)Merr) Varieties
… of fresh and dried seed, initial seed vigour and accelerated ageing test. Seed was artificially aged at each harvest for varying periods(1,2, 3, 4, 5, 6 and 7 days) after which germination and vigour tests were done. The results showed that variety had significant effect on vigour of artificially …
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Effect of Harvest date on seed quality and potential longevity of two Soyabeans(Glycine max(L.)Merr) Varieties
… of fresh and dried seed, initial seed vigour and accelerated ageing test. Seed was artificially aged at each harvest for varying periods(1,2, 3, 4, 5, 6 and 7 days) after which germination and vigour tests were done. The results showed that variety had significant effect on vigour of artificially …
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Ageing of HDPE Geomembranes Used to Contain Landfill Leachate or Hydrocarbon Spills
The ageing of high density polyethylene geomembrane (GM) liners used to minimize advection and diffusion of contaminants in municipal solid waste landfill leachate and in hydrocarbon spills to the environment is examined. The evaluation of the ageing of GMs used in landfills involved four …
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Long-Term Performance of HDPE Geomembranes as Landfill Liners
… based on both conventional laboratory accelerated immersion tests and simulated landfill liner tests. A 1.5mm HDPE geomembrane was immersed in different synthetic leachates at different temperatures in order to evaluate the effects of leachate chemical constituents on the depletion of …
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An investigation of the factors affecting the degradation of cellulose acetate artefacts in museum collections
… of various ages and degrees of degradation using accelerated ageing and comparing these results to those for naturally aged samples. Initial work has been carried out to investigate the plastic each artefact is made from and also its chemical composition. Various analytical techniques have been …
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Reducing the risk of open display: optimising the preventive conservation of historic silks
… plain silks were the study’s focus. Year long accelerated ageing experiments have demonstrated that although the inclusion of UV radiation during light ageing increased the rate of deterioration, light ageing caused small changes to silk. Thermal ageing with different humidity levels …
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Material selection and manufacture for a polymer heart valve application
… and mechanical properties before and after accelerated ageing by oxidation and hydrolysis. Thermal ageing in air was also studied. Collection of this qualitative and quantitative information builds a useful database of results from which to develop an understanding of the nature of …
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Investigating the Relationship between Markers of Ageing and Cardiometabolic Disease
Human ageing is accompanied by characteristic metabolic and endocrine changes, including altered hormone profiles, insulin resistance and deterioration of skeletal muscle. Obesity and diabetes may themselves drive an accelerated ageing phenotype. Untangling the causal web between ageing, obesity …
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Penetration and permanence of an organophosphate and a pyrethroid in structural wood for insect control
… and lack of ovicidal effect with chlorpyrifos. Accelerated ageing studies employing an environmental chamber (40°C, 70% RH) at a 1:6 ratio of accelerated to natural weathering indicated no significant difference in surface or below-surface concentrations of permethrin in wood aged artificially …
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