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Full-Text Articles in Engineering

Direct Air Capture: Catalyzing A Carbon Negative Future, Tagg K. Lee Jan 2023

Direct Air Capture: Catalyzing A Carbon Negative Future, Tagg K. Lee

Civil and Environmental Engineering Publications

Direct Air Capture (DAC) technology has emerged as a promising means to address the escalating challenges of atmospheric carbon dioxide (CO2) levels and mitigate climate change. This paper provides an elementary overview of DAC, encompassing its underlying principles, technological advancements, and associated challenges. Point Source Carbon Capture is compared against Direct Air Capture with a solid or liquid sorbent, and physisorbents/chemisorbents are outlined. The past decade has seen a steep rise in the usage of chemical sorbents in particular, which are explored alongside their regeneration processes. This review provides an introductory explanation for the mechanisms of common DAC …


Nanostructured Carbon Materials For Active And Durable Electrocatalysts And Supports In Fuel Cells, Adam Riese Sep 2015

Nanostructured Carbon Materials For Active And Durable Electrocatalysts And Supports In Fuel Cells, Adam Riese

Electronic Thesis and Dissertation Repository

Meeting the energy demands of the future will require a breadth of technologies and materials for generating and converting electricity. Increasing activity and reducing costs of electrocatalysts for fuel cells is among the most important challenges for the technology. With advances in nanomaterials there has been increased interest in creating novel catalysts with both high activity and excellent long-term durability. This thesis aims to understand how modification of nanostructured carbons can be used to improve the activity and durability of catalysts and supports for the oxygen reduction reaction (ORR). Using an integrating approach to synthesis, characterization, and electrochemical testing, it …


Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu Dec 2012

Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu

Electronic Thesis and Dissertation Repository

This dissertation explored topographic controls on spatial and temporal patterns in water yield and nutrient (carbon, nitrogen and phosphorus) export from forested headwater catchments in the Turkey Lakes Watershed in central Ontario, where other factors contributing to differences in water yield and nutrient export, including climate, geology, forest, and soils, are relatively constant. Topographic characteristics, including (a) hydrological flushing potential (expansion of water table into nitrate-N producing areas); (b) hydrological storage potential (area of wetlands, which can alternatively allow water and nutrients to bypass wetlands when storage capacity is filled with water or to trap them when not filled); and …