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Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González Nov 2014

Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González

Steven J. Hall

Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments was equivalent to more than two times the annual fine litterfall mass and nutrient content in control …


Design And Synthesis Of Chelating Compounds And Solid-Supported Chelators For Metal Depleted Solutions, Surendra Dawadi Jul 2014

Design And Synthesis Of Chelating Compounds And Solid-Supported Chelators For Metal Depleted Solutions, Surendra Dawadi

Dissertations

Metals are essential to life, yet they can be toxic for biological systems when present in excessive amounts. The major source of metal overload in humans is diet; and in some cases, intravenous feeding. Thus the removal of toxic metal ions from contaminated clinical products such as total parenteral nutrition (TPN) solutions, and drinking and waste water is extremely important. The use of chelating resins, which are polymeric solids containing covalently immobilized chelating compounds, for the selective removal of metal ions from contaminated solutions has been conceptualized long ago. Herein, the design and synthesis of metal specific chelating compounds and …


Facile Synthesis And Characterization Of A Thermally Stable Silica-Doped Alumina With Tunable Surface Area, Porosity, And Acidity, Maryam Khosravi Mardkhe Mar 2014

Facile Synthesis And Characterization Of A Thermally Stable Silica-Doped Alumina With Tunable Surface Area, Porosity, And Acidity, Maryam Khosravi Mardkhe

Theses and Dissertations

Mesoporous γ-Al2O3 is one of the most widely used catalyst supports for commercial catalytic applications. The performance of a catalyst strongly depends on the combination of textural, chemical and physical properties of the support. Pore size is essential since each catalytic system requires a unique pore size for optimal catalyst loading, diffusion and selectivity. In addition, high surface area and large pore volume usually result in higher catalyst loading, which increases the number of catalytic reaction sites and decreases reaction time. Therefore, determination of surface area and porosity of porous supports is critical for the successful design and optimization of …


Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson Jan 2014

Monitoring The Influence Of Acid Deposition On Soil And Implications To Forest Health In The Daniel Boone National Forest, Tyler M. Sanderson

Theses and Dissertations--Forestry and Natural Resources

Combustion of fossil fuels has contributed to many environmental problems including acid deposition. The Clean Air Act (CAA) was created to reduce ecological problems by cutting emissions of sulfur and nitrogen. Reduced emissions and rainfall concentrations of acidic ions have been observed since the enactment of the CAA, but soils continue to receive some acid inputs. Soils sensitive to acid deposition have been found to have low pH, a loss of base cations and a shift in the mineral phase controlling the activity of Al3+ and/or SO42-. If inputs continue, soil may be depleted of base …


Spin-Mediated Transport In Superconducting And Spin-Polarized Systems, Joseph C. Prestigiacomo Jan 2014

Spin-Mediated Transport In Superconducting And Spin-Polarized Systems, Joseph C. Prestigiacomo

LSU Doctoral Dissertations

The effects of spin-imbalance on the electronic transport properties of spin-polarized and superconducting systems have been studied in detail. The transport properties of the quaternary Heusler alloys Co2MnSi1-xAlx (0≤x≤1), which have been theoretically predicted to develop a half-metallic band structure as x→0, were investigated. Resistivity versus temperature measurements as a function of Al concentration (x) revealed a systematic reduction in the residual resistivity ratio as well as a transition from weakly-localized to half-metallic conduction as x→0. From measurements of the ordinary and anomalous Hall effects, the charge carrier concentration was found to increase, while the anomalous Hall coefficient decreased by …