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 15 of 15 for “"Active layer thickness"”.
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Analysis of microtopography, vegetation, and active-layer thickness using terrestrial LIDAR and kite photography, Barrow, AK
… change. This study examined changes in the active layer of permafrost near Barrow, Alaska at very fine scale to capture subtle changes related to microtopography and landcover. In 2010, terrestrial LIDAR was used to collect high-resolution elevation data for four 10 m × 10 m plots where …
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Analysis of microtopography, vegetation, and active-layer thickness using terrestrial LIDAR and kite photography, Barrow, AK
… change. This study examined changes in the active layer of permafrost near Barrow, Alaska at very fine scale to capture subtle changes related to microtopography and landcover. In 2010, terrestrial LIDAR was used to collect high-resolution elevation data for four 10 m × 10 m plots where …
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Effect of feed temperature on the performance and properties of the NF270 membrane
… of the membrane: pore radius, effective active layer thickness, and volumetric charge density. From 25°C to 40°C, the fitted parameters showed a 29% increase in pore size, and an 84% increase in effective active layer thickness; volumetric charge density increased in magnitude by …
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Forced and Unforced Permafrost Changes in the Northern Hemisphere during 1901-2100
… in both spatial and temporal coverage. Active layer thickness (ALT) modeling is another approach that can overcome many of these limitations, but the models have large uncertainty in predicting future permafrost changes.This doctoral research firstly investigated the impacts of climate …
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Resonant Cavity Enhanced Photodetectors and Optoelectronic Switches
… the quantum efficiency without increasing the active layer thickness to optimize the bandwidth. The resonant cavity enhanced (RCE) detection scheme can be used in many different detector designs to improve the device sensitivity without any detrimental effects on the device speed. This thesis …
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P3HT:PCBM-based organic solar cells : Optimisation of active layer nanostructure and interface properties.
… C[61] butyric acid methyl ester (PCBM) as an active layer in the ratio of (1:1) (P3HT:PCBM). The efficiency and stability of P3HT:PCBM-based solar cells have been examined using different methods and employing novel materials such as1-[N-(2-ethoxyethyl) pent-4-ynamide] -8 (11), 15 (18), 22 …
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Vegetation Succession and Environmental Relations at the Illisarvik Drained Lake Experiment, Western Arctic Coast, Canada
… height were the primary factors controlling active-layer thickness and ground temperatures at Illisarvik. The vegetation height likely acts as a proxy for the insulating influence of the snow.
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Internal composition, structure, and hydrological significance of rock glaciers in the Eastern Cascades, Washington
… permafrost) is insulated by an outer debris layer, react slowly to climate change, thus acting as sinks for ice and liquid water storage in mountain environments. This study utilized ground penetrating radar (GPR) to investigate the internal structure, composition, and hydrological …
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A Framework for Evaluating Thaw Settlement in Permafrost Regions
… that combines TSPI with predicted changes in active layer thickness. The ITSH enables early identification of areas prone to thaw settlement, informing planning prior to site investigations. Finally, these contributions were synthesized into a Thaw Settlement Evaluation Framework, offering …
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Land-atmosphere exchange of carbon in a high-Arctic wet tundra ecosystem
… temperature, gross primary production (GPP), active layer thickness and soil organic acids. The spatial variability in CH4 fluxes was closely correlated to water table depth (WtD), species compo-sition and soil organic acids. The CH4 fluxes remained low during autumn and early winter of both …
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Subarctic ecosystem responses to climate, catchment and permafrost dynamics in the Holocene
… permafrost decay. A high nutrient/productivity layer in the other lake between 1900 and 1800 cal BP may have been related to the same event in the mire. Sedge peat accumulated from 1350 cal BP. Renewed permafrost aggradation is indicated indirectly around 700 cal BP and directly 120 cal BP from …
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The isolation and study of rheological and mass transfer parameters in the spinning of advanced hollow fibre membranes for gas separation
… effect of extrusion shear on membrane active layer thickness and the subtle effects of forced convection residence time. The fibres produced displayed above recognised intrinsic selectivities for the gas separations studied and this was attributed to shear enhanced molecular orientation …
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Generation, recombination and extraction of charges in polymer
… Further optimization of the blend ratio, active layer thickness, and polymer molecular weight resulted in 6.6% efficiency for F-PCPDTBT:PC70BM solar cells. Interestingly, the double fluorinated version 2F-PCPDTBT exhibited poorer FF despite a further reduction of geminate and non-geminate …
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Rotary kiln transport phenomena: a study of the bed motion and heat transfer
… by a yield criterion. By considering the active layer (the shearing region near the bed surface) to be thin, relative to the chord length, the applied granular flow equations reduce to the boundary layer equations of Prandtl, which are solved to obtain the active layer thickness and the …