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 “"Nitrogen addition"”.
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Flame deposition of diamond : gas phase diagnostics and the effects of nitrogen addition
Contains fulltext : 19317_flamdeofd.pdf (Publisher’s version ) (Open Access)
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Interactive effects of chronic nitrogen addition and pulsed deluge events on community structure and function of the shortgrass steppe
… resources such as atmospheric CO2 and reactive nitrogen. Patterns of perturbations can be evaluated through the "pulse-press" framework which describes resource alteration along a temporal continuum: from discrete, short-term "pulse" to chronic, long-term "press". The combination of chronic …
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Carbon storage in grasslands : the impact of atmospheric nitrogen pollution
Atmospheric nitrogen deposition is a major threat to biodiversity and ecosystem service provision around the globe. It is known that nitrogen enrichment affects various chemical and biological processes involved in carbon cycling and storage in soil. This is especially significant as soil carbon …
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ELECTROSTATIC (LANGMUIR) PROBE MEASUREMENTS IN RF DRIVEN He, N2, BCl3, AND BCl3/N2 PLASMAS
… observed etch rate enhancement of GaAs with nitrogen addition. The system was validated in both helium and nitrogen plasmas. Probe measurements showed that as the nitrogen concentration in BCl3/N2 plasmas increased, the average electron energy actually decreased (5.52 eV @ 0% N2, 4.14 eV @ …
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La influencia de la tecnología de la vinificación en la microbiología y el desarrollo de la fermentación alcohólica
… by vacuum filtering. The resources studied: Nitrogen addition (diammonium phosphate and commercial activator with ammonium sulfate), Aeration (by oxygen addition direct and racking), Survival factors addition (Ergosterol), Yeast hulls addition and inert cellulose substrates addition (tree …
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The role of nitrogen on the flotation performance of a complex sulphide ore
This thesis focuses on the role of nitrogen on flotation performance of a sulphide PGM ore. Merensky ore obtained from Impala Platinum mine, Rustenburg, was used in laboratory batch flotation tests. Nitrogen addition was implemented during the conditioning and / or flotation stages of the test. In …
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Autoignition and emission characteristics of gaseous fuel direct-injection compression-ignition combustion
… the effects of ethane, hydrogen and nitrogen addition) were studied. An experimental investigation was carried out on a shock tube facility. Ignition delay, ignition kernel location, and NOx emissions were measured. The results indicated that the addition of ethane to the fuel …
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An investigation of the effects of the addition of powdered activated carbon to the activated sludge of cellulose acetate manufacturing wastewater
… the stimulation of greater biomass growth. PAC addition increased the oxygen uptake rate (OUR), the observed cell yield coefficient (Ybbs) and the first order substrate removal coefficient (Kb) of the activated sludge system, which were operated at a temperature of 18°C and a biological solids …
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Fundamental studies of mixed gas plasmas in ICP-MS
… or removing these interference effects. In addition the use of mixed gas plasmas for sensitivity enhancement has been assessed using both wet and dry sample introduction systems. Simplex optimization procedures have been used throughout. The addition of nitrogen to all three argon gas flows …
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Phytoplankton Ecology in the Skidaway River Estuary
… either nutrient enrichment (phosphorous and/or nitrogen addition) or control treatments. Within and among all sampling periods the phytoplankton community was dominated by large diatoms including Coscinodiscus and Nitzschia species, and other taxa including chlorophytes like Nannochloropsis and …
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Seasonal, biogeochemical, and microbial response of soils to simultaneous warming and nitrogen additions
<p>Climate warming and nitrogen deposition are global environmental threats that could alter soil microbial communities and the biogeochemical processes they perform. Few studies have examined interactive effects of elevated temperatures and nitrogen inputs. Many studies have also not considered …
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Interactions, Heterogeneity, and the Determinants of Multispecies Coexistence
… chapter one, I examine how changes in resources (nitrogen availability) and natural enemies (foliar pathogens) modify the mechanisms of plant diversity and composition. To do that, I quantify the intrinsic growth rates and interaction coefficients between eight common Central European perennial …
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Arsenic in the Pak Pa-Nang River Basin, Thailand
… digestion procedure, followed by carrier gas nitrogen addition (N2)-ICP-MS analysis, to overcome argon chloride (40Ar35Cl+) interference, was used to measure total arsenic. Validation for these procedures was carried out using certified reference materials and real samples, mussel, cockle, …
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Ectomycorrhizal associations in tropical montane forest: insights into their influence on nutrient cycling and functional responses to soil fertility
… on EM fungal compositional variation. In addition, analysis of the phylogenetic beta diversity for Russula, the most abundant and diverse EM genus in the community, revealed that Russula species show greater than expected phylogenetic dissimilarity among taxa occupying sites with …
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The use of rockdust and composted materials as soil fertility amendments
… on plant yield that were attributed to nitrogen addition by compost and manure. NPK chemical fertilizer produced a yield effect at an earlier point in the trial compared to manure and compost. This, and the chemical analysis of the materials showed that the organic materials required a …
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Analysis of the quantity and cost of modelled nitrate deposition to the Vaal River from power station emissions with insights for cost-benefit analysis and policy recommendations
… processes have led to high levels of reactive nitrogen entering freshwater ecosystems. This increase in reactive nitrogen levels has caused several adverse environmental and health effects and has resulted in higher deposition rates of nitrates to freshwater ecosystems. The costs and benefits …
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The link between Permeable Interlocking Concrete Pavement (PICP) design and nutrient removal
… for the treatment of various nutrients (ammonia-nitrogen, orthophosphate-phosphorus and nitrate-nitrogen) commonly found in stormwater runoff. Ten experimental cells each housing a different permeable pavement design were constructed in the NEB laboratory at the UCT. Infiltration tests (ASTM …