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Physical Sciences and Mathematics

2019

Carbon

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Effects Of Detritivores On Nutrient Dynamics And Corn Biomass In Mesocosms, Josephine Lindsey-Robbins, Angélica Vázquez-Ortega, Kevin Mccluney, Shannon Pelini Dec 2019

Effects Of Detritivores On Nutrient Dynamics And Corn Biomass In Mesocosms, Josephine Lindsey-Robbins, Angélica Vázquez-Ortega, Kevin Mccluney, Shannon Pelini

School of Earth, Environment and Society Faculty Publications

(1) Background: Strategies aimed at managing freshwater eutrophication should be based on practices that consider cropland invertebrates, climatic change, and soil nutrient cycling. Specifically, detritivores play a crucial role in the biogeochemical processes of soil through their consumptive and burrowing activities. Here, we evaluated the effectiveness of increasing detritivore abundance as a strategy for nutrient management under varied rainfall. (2) Methods: We manipulated soil macroinvertebrate abundance and rainfall amount in an agricultural mesocosms. We then measured the phosphorus, nitrogen, and carbon levels within the soil, corn, invertebrates, and soil solution. (3) Results: Increasing detritivore abundance in our soil significantly increased …


Identifying The N Sources For Black Mangrove (Avicennia Germinans) In A South Texas Mangrove Forest, Ashley Elizabeth Murphy Dec 2019

Identifying The N Sources For Black Mangrove (Avicennia Germinans) In A South Texas Mangrove Forest, Ashley Elizabeth Murphy

Theses and Dissertations

Black mangrove (Avicennia germinans) in south Texas provide ecosystem services and benefits to humans including: habitat for wildlife, prevention of coastline erosion, and mitigation of natural disasters. One step to preserve their ecological functions is to identify and protect the source of their nitrogen (N). Nitrogen stable isotopes were sampled for one year beginning August 2018 and used as tracers to identify how mangroves obtain N. Total N in (A. germinans) and associated (Batis maritima) (plants) (2.1%) was more abundant than in cyanobacteria (0.6%) and sediment (0.1%). Plant d15N signatures (5.52‰) were more similar to sediment (5.21‰) than cyanobacteria (1.98‰), …


Cost Effectiveness Of Greenhouse Gas Reductions Through Afforestation Of Agricultural Land In The Arkansas Delta, Karli A. Moore Dec 2019

Cost Effectiveness Of Greenhouse Gas Reductions Through Afforestation Of Agricultural Land In The Arkansas Delta, Karli A. Moore

Graduate Theses and Dissertations

Sequestration of atmospheric carbon in forested lands offsets carbon emissions from other industries. Conversion of private lands, particularly agricultural tracts in marginal areas, to forests can bolster carbon abatement. The United States government agencies administer some voluntary, incentive-based programs to encourage landowners to adopt production practices with positive environmental outcomes. This policy stream can be used to increase transition of marginal agricultural land to forests, thereby creating new carbon sinks. We analyze an eleven-county study area in the Arkansas Delta to determine feasibility for a subsidy focused on carbon abatement through afforestation. This study area is significant for two reasons: …


Reconstructing Geographic And Trophic Histories Of Fish Using Bulk And Compound-Specific Stable Isotopes From Eye Lenses, Amy A. Wallace Nov 2019

Reconstructing Geographic And Trophic Histories Of Fish Using Bulk And Compound-Specific Stable Isotopes From Eye Lenses, Amy A. Wallace

USF Tampa Graduate Theses and Dissertations

The present research examined the viability and utility of eye lenses as a source of lifetime stable-isotope records in fish. It is presented in three sections. The first section compared bulk isotopic variation (bulk analysis) within fish eye-lenses at two temporal resolutions and compared patterns obtained from left and right eyes. The first temporal resolution was lower in an attempt to expose broad-scale isotopic changes during life while reducing effort and cost. This approach did reveal lifetime patterns, but tended to miss certain life events, particularly during early life. The second resolution was higher and provided detail that was missed …


Measurements Of The 16c + 12c And 16c + 13c Fusion Cross Sections With Implications For Astrophysics, Ashley Ann Hood Nov 2019

Measurements Of The 16c + 12c And 16c + 13c Fusion Cross Sections With Implications For Astrophysics, Ashley Ann Hood

LSU Doctoral Dissertations

The fusion of neutron-rich nuclei is of interest to nuclear astrophysics and nuclear structure. X-ray superbursts are powered by runaway thermonuclear burning deep inside of a neutron star, where heating from the pycnonuclear fusion of neutron-rich isotopes is an important heat source. Experimental measurements of fusion cross sections of neutron-rich isotopes have provided insights regarding nucleon transfer and nuclear structure properties affecting fusion. Recently, the 15C + 12C total fusion cross section was measured using a 15C beam produced by the in-flight beam production facility, which is part of the Argonne Tandem LINAC Accelerator System (ATLAS) at …


Magnetic Mineral Diagenesis In The River‐Dominated Inner Shelf Of The East China Sea, China, Can Ge, Weiguo Zhang, Chenyin Dong, Yan Dong, Jinyan Liu, Nguyen Thi Thu Hien, Huan Feng, Lizhong Yu Nov 2019

Magnetic Mineral Diagenesis In The River‐Dominated Inner Shelf Of The East China Sea, China, Can Ge, Weiguo Zhang, Chenyin Dong, Yan Dong, Jinyan Liu, Nguyen Thi Thu Hien, Huan Feng, Lizhong Yu

Huan Feng

The inner shelf of the East China Sea is a river-dominated margin characterized by fine-grained mud deposits and a rapid sedimentation rate. Three short sediment cores (similar to 2.7m in length) were examined to characterize spatial variations in magnetic mineral diagenesis. The sediment cores were analyzed for sedimentation rates, magnetic properties, particle size distribution, organic carbon, and total sulfur content. The two more proximal cores with higher sedimentation rates (similar to 2.2cm/yr and similar to 0.96cm/yr) do not exhibit obvious effects of reductive dissolution of magnetite with increasing depth, which is consistent with their lower total sulfur content. The offshore …


Life History Through The Eyes Of A Hogfish: Evidence Of Trophic Growth And Differential Juvenile Habitat Use, Meaghan E. Faletti Oct 2019

Life History Through The Eyes Of A Hogfish: Evidence Of Trophic Growth And Differential Juvenile Habitat Use, Meaghan E. Faletti

USF Tampa Graduate Theses and Dissertations

Understanding ontogenetic linkages among fish habitats is critical for conservation of fish populations and the ecosystems on which they rely. Natural tags such as stable isotopes are an effective tool commonly used to investigate ecological questions regarding fish movement and habitat use. Here, I analyzed stable isotopes from the sequentially deposited laminae of Hogfish (Lachnolaimus maximus) eye lenses from the eastern Gulf of Mexico (eGOM) to investigate trophic and geographic changes across individual life histories. I documented evidence of entire-life scale trophic growth through increases in δ15N. I also observed depth separation at the juvenile stage, evidenced by variation in …


Payment For Ecosystem Services: Incentives To Support Environmental Quality & Farming In Vermont, Stephen Posner, Taylor Ricketts, Eric Roy Oct 2019

Payment For Ecosystem Services: Incentives To Support Environmental Quality & Farming In Vermont, Stephen Posner, Taylor Ricketts, Eric Roy

Reports and Policy Briefs

Environmental quality is an ongoing concern in the Lake Champlain Basin. Vermont farmers are in a unique position to manage land in a way that maintains and improves environmental quality. A payment for ecosystem services (PES) program for Vermont would both support the economic vi- ability of Vermont farms and incentivize farmers to improve water quality and soil health. How- ever, conceptual and practical implementation challenges remain.


Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki Oct 2019

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki

Electrical & Computer Engineering Theses & Dissertations

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J/cm2) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C4+ are observed. When no acceleration voltage is applied between …


Topological Nodal Line Semimetals In Graphene Network Structures, Jian-Tao Wang, Hongming Weng, Chengfeng Chen Jul 2019

Topological Nodal Line Semimetals In Graphene Network Structures, Jian-Tao Wang, Hongming Weng, Chengfeng Chen

Physics & Astronomy Faculty Research

Topological semimetals are a fascinating class of quantum materials that possess extraordinary electronic and transport properties. These materials have attracted great interests in recent years for their fundamental significance and potential device applications. There have been intensive studies suggested that three-dimensional graphene networks support topological semimetals with two types of continuous nodal lines: one is to form closed nodal rings in Brillouin zone and the other ones traversing the whole Brillouin zone to be periodically connected. Carbon has negligible spin-orbit coupling, non-magnetism and great diversity of allotropes, which makes it very promising in realizing topological nodal line semimetals. Here we …


The Climate Sensitivity Of Carbon, Timber, And Species Richness Covaries With Forest Age In Boreal–Temperate North America, Dominik Thom, Marina Golivets, Laura Edling, Garrett W. Meigs, Jesse D. Gourevitch, Laura J. Sonter, Gillian L. Galford, William S. Keeton Jul 2019

The Climate Sensitivity Of Carbon, Timber, And Species Richness Covaries With Forest Age In Boreal–Temperate North America, Dominik Thom, Marina Golivets, Laura Edling, Garrett W. Meigs, Jesse D. Gourevitch, Laura J. Sonter, Gillian L. Galford, William S. Keeton

Rubenstein School of Environment and Natural Resources Faculty Publications

Climate change threatens the provisioning of forest ecosystem services and biodiversity (ESB). The climate sensitivity of ESB may vary with forest development from young to old-growth conditions as structure and composition shift over time and space. This study addresses knowledge gaps hindering implementation of adaptive forest management strategies to sustain ESB. We focused on a number of ESB indicators to (a) analyze associations among carbon storage, timber growth rate, and species richness along a forest development gradient; (b) test the sensitivity of these associations to climatic changes; and (c) identify hotspots of climate sensitivity across the boreal–temperate forests of eastern …


Estuarine Dissolved Organic Carbon Flux From Space: With Application To Chesapeake And Delaware Bays, Sergio R. Signorini, Antonio Mannino, Marjorie A.M. Friedrichs, Pierre St-Laurent, John Wilkin, Aboozar Tabatabai, Raymond G. Najjar, Eileen E. Hofmann, Fei Da, Hanqin Tian, Yuanzhi Yao Jun 2019

Estuarine Dissolved Organic Carbon Flux From Space: With Application To Chesapeake And Delaware Bays, Sergio R. Signorini, Antonio Mannino, Marjorie A.M. Friedrichs, Pierre St-Laurent, John Wilkin, Aboozar Tabatabai, Raymond G. Najjar, Eileen E. Hofmann, Fei Da, Hanqin Tian, Yuanzhi Yao

CCPO Publications

This study uses a neural network model trained with in situ data, combined with satellite data and hydrodynamic model products, to compute the daily estuarine export of dissolved organic carbon (DOC) at the mouths of Chesapeake Bay (CB) and Delaware Bay (DB) from 2007 to 2011. Both bays show large flux variability with highest fluxes in spring and lowest in fall as well as interannual flux variability (0.18 and 0.27 Tg C/year in 2008 and 2010 for CB; 0.04 and 0.09 Tg C/year in 2008 and 2011 for DB). Based on previous estimates of total organic carbon (TOCexp) exported by …


Facilitating Greenhouse Gas Reduction And Climate Change Adaptation Within The Coastal Zone: A Policy Analysis For The California Coastal Commission, Nicole Young May 2019

Facilitating Greenhouse Gas Reduction And Climate Change Adaptation Within The Coastal Zone: A Policy Analysis For The California Coastal Commission, Nicole Young

Master's Theses

California is already experiencing impacts to its coastline due to climate change, and more severe impacts are anticipated if greenhouse gas emissions continue to rise. These climate change impacts are especially strong within the California coastal zone, which falls under the jurisdiction of the California Coastal Commission. The Commission has a history of rigorous environmental protection and is committed to protecting California’s coast through proactive planning and regulation, however they will need to initiate coastal policies with ambitious targets to facilitate effective climate change adaptation and mitigation. This study analyzed existing California climate policies and Coastal Commission policies to identify …


Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon May 2019

Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon

Senior Theses

Two-dimensional materials exhibit properties unlike anything else seen in conventional substances. Electrons in these materials are confined to move only in the plane. In order to explore the effects of these materials, we have built apparatus and refined procedures with which to create two-dimensional structures. Two-dimensional devices have been made using exfoliated graphene and placed on gold contacts. Their topography has been observed using Atomic Force Microscopy (AFM) confirming samples with monolayer, bilayer, and twisted bilayer structure. Relative work functions of each have been measured using Kelvin Probe Force Microscopy (KPFM) showing that twisted bilayer graphene has a surface potential …


Deposition Of Platinum Particles On Surface-Modified Carbon Ultramicroelectrodes, Caitlin Millsaps May 2019

Deposition Of Platinum Particles On Surface-Modified Carbon Ultramicroelectrodes, Caitlin Millsaps

Undergraduate Honors Theses

Nanoparticles are used as electrocatalysts due to their large surface area-to-volume ratios. Most studies of nanoparticle electrocatalysis are performed on collections of particles on a support, which represent ensemble average behavior influenced by spatial distribution of the nanoparticles. Therefore, recent emphasis has been placed on analyzing electrocatalytic behavior of single particles. The focus here is to develop carbon ultramicro- and nanoelectrode platforms for studying the electrocatalytic properties of single metal nanoparticles. Ultramicroelectrodes were prepared using chemical vapor deposition of carbon in pulled quartz capillaries. Electrode diameters were determined by cyclic voltammetry. Electrodes were modified using a soft nitriding technique to …


Endolithic Microbial Carbon Cycling In East Antarctica, Natalie Tyler Apr 2019

Endolithic Microbial Carbon Cycling In East Antarctica, Natalie Tyler

Theses and Dissertations

Microbes adapt to inhospitable conditions by colonizing niches that protect them from severe environmental conditions, making them model organisms in the search for life on other planets. Endoliths are globally ubiquitous microbes that colonize structural cavities within rocks, which protect them from environmental stressors while maintaining access to nutrition and light sources. Despite harsh katabatic winds, extreme temperature fluctuations, harmful UV radiation and exposure to desiccation, endolithic communities have been observed in Antarctica. Previous studies have found viable and abundant microbial biomass through microscopy and the addition of isotopic labels. However, due to the slow metabolic activity of these microbes, …


Stable Isotope Analysis Of Japan Sea And East China Sea Sediments: Late Pleistocene Paleoceanographic Reconstructions, Heather Dawn Black Mar 2019

Stable Isotope Analysis Of Japan Sea And East China Sea Sediments: Late Pleistocene Paleoceanographic Reconstructions, Heather Dawn Black

FIU Electronic Theses and Dissertations

The East Asian Monsoon system is an important dynamic of East Asian climates, affecting over one-third of the world’s population. Marginal seas within East Asia are ideal environments to study past fluctuations of monsoon intensities and durations as they are sensitive to climatic and glacio-eustatic sea level changes. This study focuses on continuous sedimentary sequences collected from three Integrated Oceanic Drilling Program Expedition 346 sites; Sites U1426 and U1427 in the Japan Sea and Site U1429 in the East China Sea. Elemental concentration (%TOC, %TN, and %CaCO3) and stable isotope ratios (δ13C and δ15N) …


Environmental Controls On Dissolved Carbon Export And River Geochemistry - A Case Study In The Mississippi-Atchafalaya System, Jeremy Reiman Mar 2019

Environmental Controls On Dissolved Carbon Export And River Geochemistry - A Case Study In The Mississippi-Atchafalaya System, Jeremy Reiman

LSU Master's Theses

Rivers serve as an important medium for the exchange of elements between land, ocean, and atmosphere. This thesis consists of three interconnected studies with the overarching goal of analyzing the environmental factors influencing dissolved carbon dynamics and river geochemistry in large rivers. These studies utilized river water samples and in-stream measurements collected from the Mississippi and Atchafalaya Rivers at hourly to monthly intervals between 2013 to 2018, along with ambient river and meteorological data downloaded from public-access databases. Results indicate substantially higher dissolved organic carbon concentrations (DOC, 611 ±181 µmol L-1) but lower concentrations of dissolved inorganic carbon …


Carbon Dioxide Measurement In Irish Blanket Peatlands: An Assessment Of Pool-Soil Flux Variability, Mariya Radomski, Alan Gilmer, Vivienne Byers, Eugene Mcgovern Jan 2019

Carbon Dioxide Measurement In Irish Blanket Peatlands: An Assessment Of Pool-Soil Flux Variability, Mariya Radomski, Alan Gilmer, Vivienne Byers, Eugene Mcgovern

Articles

Peatlands have been recognised as having a significant role in the mediation of atmospheric carbon dioxide (CO2) levels with direct implications for global climate change. Longitudinal in situ measurement systems for CO2 concentrations in blanket peatland ecosystems are difficult to implement where the nature of terrestrial–aquatic connectivity and hydrodynamics have a significant effect on the carbon cycle. The need for greater data on CO2 concentrations and flux monitoring in these settings has been well recognised. However, applying the most appropriate monitoring approach presents a special challenge. This paper sets out the development of a direct method for field based longitudinal …


Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse Jan 2019

Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse

Legacy Theses & Dissertations (2009 - 2024)

This dissertation presents theoretical and experimental studies in carbon nanotubes (CNTs), graphene, and van der Waals heterostructures. The first half of the dissertation focuses on cutting edge tight-binding-based quantum transport models which are used to study proton irradiation-induced single-event effects in carbon nanotubes [1], total ionizing dose effects in graphene [2], quantum hall effect in graded graphene p-n junctions [3], and ballistic electron focusing in graphene p-n junctions [4]. In each study, tight-binding models are developed, with heavy emphasis on tying to experimental data. Once benchmarked against experiment, properties of each system which are difficult to access in the laboratory, …


Electrostatically Assembled Construction Of Ternary Tio2-Cu@C Hybrid With Enhanced Solar-To-Hydrogen Evolution Employing Amorphous Carbon Dots As Electronic Mediator, Jiaxin Zhu, Mengmeng Zhang, Jinyan Xiong, Yinan Yan, Weijie Li, Gang Cheng Jan 2019

Electrostatically Assembled Construction Of Ternary Tio2-Cu@C Hybrid With Enhanced Solar-To-Hydrogen Evolution Employing Amorphous Carbon Dots As Electronic Mediator, Jiaxin Zhu, Mengmeng Zhang, Jinyan Xiong, Yinan Yan, Weijie Li, Gang Cheng

Australian Institute for Innovative Materials - Papers

The huge demand for renewable hydrogen produced by water splitting has prompted people to conduct in-depth research on the hydrogen evolution reaction for the development of earth-abundant, non-precious, and multi-functional metal catalysts. Herein, a noble-metal-free ternary composite of TiO2-Cu@C was prepared by electrostatic self-assembly loaded copper nanoparticles and amorphous carbon dots (CDs) on porous TiO2 microrods. The good conductivity of the CDs was beneficial to promoting the charge transfer and separation, generating an enhanced solar-to-hydrogen performance on TiO2-Cu@C. The optimized TiO2-Cu@C reveals a stable and notable hydrogen evolution rate of 3911 μmol g−1h−1, which is 1.6 times that of TiO2-Cu …


Bio‑Derived Hierarchical Multicore-Shell Fe2n‑Nanoparticle‑Impregnated N‑Doped Carbon Nanofiber Bundles: A Host Material For Lithium‑/Potassium‑Ion Storage, Hongjun Jiang, Ling Huang, Yunhong Wei, Boya Wang, Hao Wu, Yun Zhang, Hua-Kun Liu, Shi Xue Dou Jan 2019

Bio‑Derived Hierarchical Multicore-Shell Fe2n‑Nanoparticle‑Impregnated N‑Doped Carbon Nanofiber Bundles: A Host Material For Lithium‑/Potassium‑Ion Storage, Hongjun Jiang, Ling Huang, Yunhong Wei, Boya Wang, Hao Wu, Yun Zhang, Hua-Kun Liu, Shi Xue Dou

Australian Institute for Innovative Materials - Papers

Despite the significant progress in the fabrication of advanced electrode materials, complex control strategies and tedious processing are often involved for most targeted materials to tailor their compositions, morphologies, and chemistries. Inspired by the unique geometric structures of natural biomacromolecules together with their high affinities for metal species, we propose the use of skin collagen fibers for the template crafting of a novel multicore-shell Fe2N-carbon framework anode configuration, composed of hierarchical N-doped carbon nanofiber bundles firmly embedded with Fe2N nanoparticles (Fe2N@N-CFBs). In the resultant heterostructure, the Fe2N nanoparticles firmly confined inside the carbon shells are spatially isolated but electronically well …


Synthesis Of Cose2-Snse2 Nanocube-Coated Nitrogen-Doped Carbon (Nc) As Anode For Lithium And Sodium Ion Batteries, Jin Bai, Huimin Wu, Shiquan Wang, Guangxue Zhang, Chuanqi Feng, Hua-Kun Liu Jan 2019

Synthesis Of Cose2-Snse2 Nanocube-Coated Nitrogen-Doped Carbon (Nc) As Anode For Lithium And Sodium Ion Batteries, Jin Bai, Huimin Wu, Shiquan Wang, Guangxue Zhang, Chuanqi Feng, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

CoSe2-SnSe2/NC nanocubes (CSNC@NC) coated by nitrogen-doped carbon (NC) were synthesized successfully by an ordinary pyrazole polymerization and carbonization process. In comparison with bare CSNC, the CSNC@NC composite exhibited good structural stability and improved electrical conductivity when used as anode. The CSNC@NC electrode showed a stable Li storage capacity (730.41 mAh g−1 over 100 cycles at 0.2 A g−1) and excellent rate performance (402.10 mAh g−1 at 2 A g−1). For Na storage, the discharge capacity could be maintained 279.3 mAh g−1 over 100 cycles at 0.2 A g−1; the lower capacity than that for Li storage maybe caused by the …


Constructing Coo/Co3s4 Heterostructures Embedded In N-Doped Carbon Frameworks For High-Performance Sodium-Ion Batteries, Can Guo, Wenchao Zhang, Yi Liu, Jiapeng He, Shun Yang, Mingkai Liu, Qinghong Wang, Zaiping Guo Jan 2019

Constructing Coo/Co3s4 Heterostructures Embedded In N-Doped Carbon Frameworks For High-Performance Sodium-Ion Batteries, Can Guo, Wenchao Zhang, Yi Liu, Jiapeng He, Shun Yang, Mingkai Liu, Qinghong Wang, Zaiping Guo

Australian Institute for Innovative Materials - Papers

Heterostructures are attractive for advanced energy storage devices due to their rapid charge transfer kinetics, which is of benefit to the rate performance. The rational and facile construction of heterostructures with satisfactory electrochemical performance, however, is still a great challenge. Herein, ultrafine hetero-CoO/Co3S4 nanoparticles embedded in N-doped carbon frameworks (CoO/Co3S4@N-C) are successfully obtained by employing metal-organic frameworks as precursors. As anodes for sodium ion batteries, the CoO/Co3S4@N-C electrodes exhibit high specific capacity (1029.5 mA h g−1 at 100 mA g−1) and excellent rate capability (428.0 mA h g−1 at 5 A g−1), which may be attributed to their enhanced electric …


Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp Jan 2019

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …


Seasonal Soil Carbon Fluxes In Transitioning Agricultural Soils In Central Washington State: Relations To Land-Use, Environmental Factors And Soil Carbon-Nitrogen Characteristics, Brandon Kautzman Jan 2019

Seasonal Soil Carbon Fluxes In Transitioning Agricultural Soils In Central Washington State: Relations To Land-Use, Environmental Factors And Soil Carbon-Nitrogen Characteristics, Brandon Kautzman

All Master's Theses

Changing agricultural land-use practices to increase soil carbon sequestration contributes to climate change mitigation and improved food security by moving CO2 from the atmosphere into soil as soil organic carbon (SOC). In 2016, a farm in Thorp, Washington, Spoon Full Farm, began converting land historically farmed using conventional methods of tillage and synthetic fertilizers to conservation farming methods with direct seeding and organic soil amendments with a goal of sequestering carbon in the soil. This project evaluates relationships of soil CO2 respiration and net ecological exchange (NEE) with land-use types, seasonal environmental factors (air temperature, relative humidity, soil …


Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji Jan 2019

Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji

Electrical & Computer Engineering Faculty Publications

Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg-1 at 2 mVs-1), higher surface capacitive contribution (75%), better stability and rate …


Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath Jan 2019

Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

Abstract: Phosgene in the atmosphere is produced via the degradation of carbon tetrachloride, methyl chloroform, and a number of chlorine‐containing very short lived substances (VSLS). These VSLS are not regulated by the Montreal Protocol even though they contribute to stratospheric ozone depletion. While observations of VSLS can quantify direct stratospheric source gas injection, observations of phosgene in the upper troposphere/lower stratosphere can be used as a marker of product gas injection of chlorine‐containing VSLS. In this work we report upper troposphere/lower stratosphere measurements of phosgene made by the ACE‐FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument and compare with results …