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 17 of 17 for “"Macroporosity"”.
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Effects of severe cattle treading on soil physical properties and pasture productivity
… had increasingly detrimental effects on soil macroporosity, saturated hydraulic conductivity (Ksai), unsaturated hydraulic conductivity (K_40), surface roughness, depths of pug prints, bare ground area, ryegrass tiller density, and herbage accumulation. Soil dry bulk density and total porosity …
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The catalytic conversion of low chain length hydrocarbons to liquid fuels using ion exchange resin
… production rate is obtained with increasing macroporosity, increasing degree of functionalization and decreasing catalyst bead size. A minimum acid strength of pKA = -2.4 is required. The liquid production rate is increased by increasing the reaction temperature and weight hourly space …
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A tour-de-force in polymer crosslinked aerogels
… Here, we report a method where an open macroporosity is introduced by pyrolysing RF aerogels whose skeletal nanoparticles have been coated conformally and crosslinked chemically with an isocyanate-derived polymer. The new macroporous material was evaluated electrochemically for possible …
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Thermomechanical Modeling of Oxidation Effects in Porous Ultra-High Temperature Ceramics
… representative volume elements (RVEs) with macroporosity volume fractions of 10%, 40% and 70% to establish a baseline for the response due to geometric effects. Compressive strains of up to 30% were applied at room temperature. The 10% and 40% RVEs showed shear banding and subsequent shear …
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Microstructure-induced capillary force effects on penetration and release in hydroxyapatite bone scaffolds
… scaffolds with both microporosity (<50µm) and macroporosity (>100µm) are known to enhance bone formation. Including microporosity in a scaffold increases bone volume and distribution. The integration of the bone with the scaffold is also improved as both cells and mineralized bone have been …
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The Influence of Trees on Soil Hydraulic Properties : Species Effects and the Provision of Ecosystem Services.
… Ks corresponded with significantly higher soil macroporosity and macropore flow. A mesocosm experiment, undertaken to investigate the influence of tree roots and associated soil macrofauna on Ks, was found to be of insufficient duration for significant changes to occur; however non-significant …
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Slash Mulching and Incorporation as Mechanical Site Preparation for Pine Plantation Establishment and Subsequent Effects on Soil Moisture and Site Hydrology
… on the pocosin study site except for soil macroporosity, which was significantly increased by bedding. Site hydrology and soil water nutrients were not significantly affected by the treatments, but seedling survival and height growth were significantly increased by bedding. Mulching had no …
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Reaction and Transport Coupling in Multi-Functional Catalysts for Selective Oxidation of Ammonia to Nitrogen
… generating pores to increase the washcoat macroporosity. Steady state reaction experiments showed a noted increase in NH3 conversion while testing NH3 oxidation the dual-layer ASC with negligible change in N2 selectivity. Modeling and analysis of ASC catalysts is presented using 1 + 1 …
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AN INVESTIGATION OF SOIL WATER MOVEMENT ON DRAINED AND UNDRAINED CLAY GRASSLAND IN SOUTH WEST ENGLAND
… which had been mole drained and so had enhanced macroporosity. Macropore flow was generated under unsaturated conditions (little matric potential response and no water table was identified). Stable oxygen concentrations were δ18O +3.5 and -5.8 in tracer and background water respectively. …
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Loblolly Pine (Pinus taeda L.) Plantation Response to Mechanical Site Preparation in the South Carolina and Georgia Piedmont
… nitrogen, foliar nitrogen, bulk density, and macroporosity were not affected by site preparation. All treatments were equally deficient in foliar nitrogen. The Shear/Disc and Shear/Rake/Disc treatments had a significantly positive relationship between foliar nitrogen and pine volume. These …
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Characterization of a Novel Biodegradable Material to Reduce Emission of Ammonia
… size distribution showed that RCC exhibited both macroporosity and mesoporosity whilst SECC showed only mesoporosity. It is interesting to note that upon steam exploding RCC, the macropores within RCC collapsed to form more mesopores in SECC. The high uptake of SECC was determined to be its small …
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Diagenetic controls on porosity, thermal history, and hydrocarbons in the Wolfcamp A, eastern Midland Basin, Texas
… of the region and the controls on carbonate macroporosity. Transmitted-light microscopy, UV-epifluorescence, cathodoluminescence, and SEM-EDS microscopy, as well as δ18O, δ13C, 87Sr/86Sr, and fluid inclusion analyses were performed. The diagenetic history could be divided into stages: Early …
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Impacts of forest harvesting on the performance of soil-landscape modelling in a radiata pine forest, northern New Zealand
… pH, available Mg, available P, available K, macroporosity, and total C) were also examined. In the third sub-study, the impacts of forest harvesting on the performance of seven techniques representing the class-based, quantitative soillandscape modelling, and geostatistical approaches to the …
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Characterizing the physical and hydraulic properties of pine bark soilless substrates
… and the addition of peat and coir lowered macroporosity, with peat having the greater effect. The total porosity inferred from the infiltration method was significantly smaller than that inferred from drainage experiments due to assumptions related to pore shape. The second study focused on …
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Additive Manufacturing Filled Polymer Composites for Environmental Contaminants: Material Extrusion Processing, Structure and Performance
… AM print process parameters to increase the macroporosity of the printed composite structure to create voids and channels allowing water infiltration and chemical adsorption to zeolite. Faster printing of larger roadways generated macrostructural voids that were maintained by extrusion at …
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Dissolved organic carbon and colour dynamics in drained and restored blanket peat
… density and ultimately reduced the degree of macroporosity within the soil. In turn, this is thought to have increased the residence time and surface area over which percolating waters flow, which is likely to have enhanced the degree of interaction with decompositional products, and thus the …
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Influence of soil bulk density and matric potential on relative gas diffusivity and urea/nitrate-derived N₂O and N₂ losses
… pore size distribution. As soil ρb increased, macroporosity (% of total soil volume) decreased by 23% while soil mesoporosity and microporosity increased by 6 and 2%, respectively. In Chapter 6, data from the previous experiments (Chapters 4 and 5) was compiled to assess the overall impact of …