Physical Sciences and Mathematics Commons^™

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 …

Modelling Carbon Nanostructures For Filtering And Adsorbing Polycyclic Aromatic Hydrocarbons, Thien Tran-Duc, Ngamta Thamwattana

Dr Ngamta Thamwattana

The discovery of carbon nanostructures, such as graphene and carbon nanotubes, has led to the creation of many novel nano-devices. In this paper, we consider an environmental application of carbon nanostructures for filtering and adsorbing polycyclic aromatic hydrocarbons (PAHs) which are environmental pollutants. We mathematically investigate the adsorption of PAHs onto a graphene sheet and determine the underlying mechanisms of suction of PAHs into a carbon nanotube. We adopt a continuum approach together with the semi-empirical Lennard-Jones potential to determine van der Waals interaction forces and energies. Results obtained here for certain PAHs are well in agreement with existing experimental …

Continuum Modelling For Carbon And Boron Nitride Nanostructures, James M. Hill, Ngamta Thamwattana

Dr Ngamta Thamwattana

Continmuum based models are presented here for certain boron nitride and carbon nanostructures.

Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher

Graduate Theses and Dissertations

Rice (Oryza sativa L.)-based cropping systems are different from other row crops due to the flood-irrigation scheme used from about one month after planting to a few weeks prior to harvest. The frequent cycling between anaerobic (i.e., flooding during the growing season) and aerobic (i.e., generally, the remainder of the year) conditions can influence the rate of soil organic matter (SOM) decomposition, which can greatly influence carbon (C) and nitrogen (N) storage and sequestration in the soil over time. Therefore, a study was conducted on a silt-loam soil (fine, smectitic, thermic, Typic Albaqualf) at the Rice Research and Extension Center …

Co2 Injection Into A Deep Saline Aquifer: Porosity Measurements, Numerical Modeling, And Costs Associated With Uncertainty Of Petrophysical Parameters, Michael John Gragg

Masters Theses

Anthropogenic levels of atmospheric greenhouse gases, particularly carbon dioxide (CO₂) have increased rapidly over the last several decades and coincide with rising temperatures globally. One possible solution is to capture CO₂ before it is released into the atmosphere by large point sources, such as fossil fuel power plants. Once captured, the CO₂ can be condensed and transported to a storage facility. Of the available options for storage of condensed CO₂, geologic sequestration in deep saline aquifers is considered the most viable option.

Porosity measurements were obtained for nearly 100 core samples of the Knox …

Shedding Light On Plant Litter Decomposition: Advances, Implications And New Directions In Understanding The Role Of Photodegradation, Jennifer Y. King, Leslie A. Brandt, E. Carol Adair

Rubenstein School of Environment and Natural Resources Faculty Publications

Litter decomposition contributes to one of the largest fluxes of carbon (C) in the terrestrial biosphere and is a primary control on nutrient cycling. The inability of models using climate and litter chemistry to predict decomposition in dry environments has stimulated investigation of non-traditional drivers of decomposition, including photodegradation, the abiotic decomposition of organic matter via exposure to solar radiation. Recent work in this developing field shows that photodegradation may substantially influence terrestrial C fluxes, including abiotic production of carbon dioxide, carbon monoxide and methane, especially in arid and semi-arid regions. Research has also produced contradictory results regarding controls on …

The Loss Of Carbon Dioxide From Activated Perbenzoate Anions In The Gas Phase: Unimolecular Rearrangement Via Epoxidation Of The Benzene Ring, David G. Harman, Aravind Ramachandran, Michelle Gracanin, Stephen J. Blanksby

Stephen Blanksby

The unimolecular reactivities of a range of perbenzoate anions (X−C6H5CO3-), including the perbenzoate anion itself (X = H), nitroperbenzoates (X = para-, meta-, ortho-NO2), and methoxyperbenzoates (X = para-, meta-OCH3) were investigated in the gas phase by electrospray ionization tandem mass spectrometry. The collision-induced dissociation mass spectra of these compounds reveal product ions consistent with a major loss of carbon dioxide requiring unimolecular rearrangement of the perbenzoate anion prior to fragmentation. Isotopic labeling of the perbenzoate anion supports rearrangement via an initial nucleophilic aromatic substitution at the ortho carbon of the benzene ring, while data from substituted perbenzoates indicate that …

Zawartość Węgla I Siarki W Pyle Pm2,5 I Pm10 W Powietrzu W Centrum Krakowa, Monika Dziugieł, Marek Bogacki, Robert Oleniacz, Marian Mazur

Robert Oleniacz

This paper presents the results of the PM2.5 and PM10 mass concentration measurements in an urban air and results obtained from the additional chemical analysis concerning carbon and sulfur content of the collected dust samples. Dust samples were collected at the measuring point located on the roof of five-storey building at the AGH University of Science and Technology in Krakow, Poland (the center of the urban area of the city). In the scope of this study the relations between the carbon and sulfur content within the collected dust samples were determined in the function of the dust fraction content and …

Agenda: Drafting Model Laws On Indoor Pollution For Developing And Developed Nations, University Of Colorado Boulder. Center For Energy & Environmental Security, Colorado Natural Resources, Energy And Environmental Law Review

Drafting Model Laws on Indoor Pollution for Developing and Developed Nations (July 12-13)

On July 12 and 13, 2012, experts convened at Colorado Law to demonstrate the extent to which a model law could help address the global problem of indoor air pollution from inefficient cook stoves. The air pollution that results from inefficiently burning biomass as fuel for cooking has serious health and climatic consequences. The workshop produced two sets of Model Laws and commentaries to help nations solve the problem, and the commentaries were published in the Colorado Natural Resources, Energy, and Environmental Law Review.

Drafting Model Laws On Indoor Pollution For Developing And Developed Nations Workshop, July 12-13, 2012, Boulder, Colorado: Introduction, Lakshman Guruswamy

Drafting Model Laws on Indoor Pollution for Developing and Developed Nations (July 12-13)

11 pages.

"This Essay introduces the framework for deliberation and legislative drafting undertaken at the workshop: Drafting Model Laws on Indoor Pollution for Developing and Developed Nations on July 12-13, 2012, in Boulder, Colorado. There are a number of fundamental premises upon which the workshop was based, and this Essay refers to the most salient among them."-- Excerpted from 24 Colo. Nat. Resources, Energy & Envtl. L. Rev. 319 (2013).

Low Energy (E, 2e) Study From The 1t₂ Orbital Of Ch₄, Shenyue Xu, Hari Chaluvadi, Xueguang Ren, Thomas Pfluger, Arne Senftleben, Chuangang Ning, Shuncheng Yan, Peng Zhang, Jie Yang, Xinwen Ma, Joachim Hermann Ullrich, Don H. Madison, Alexander Dorn

Physics Faculty Research & Creative Works

Single ionization of the methane (CH₄) 1t₂ orbital by 54 eV electron impact has been studied experimentally and theoretically. The measured triple differential cross sections cover nearly a 4π solid angle for the emission of low energy electrons and a range of projectile scattering angles. Experimental data are compared with theoretical calculations from the distorted wave Born approximation and the molecular three-body distorted wave models. It is found that theory can give a proper description of the main features of experimental cross section only at smaller scattering angles. For larger scattering angles, significant discrepancies between experiment and …

The State Of Sustainable Transportation At Union College: A Transportation Audit Of Union College Students And Faculty, Benjamin Engle

Honors Theses

Union College has established a Climate Action Plan with the goal of carbon neutrality by 2060 as part of its commitment to sustainability. A significant component of Union’s carbon footprint, however, is student and faculty transportation. The purpose of this research was to analyze the transportation behavior of students and faculty to determine the carbon emissions that result from the use of various transportation methods. Two campus‐wide surveys were conducted; one was distributed to students and the other targeted faculty. For comparison purposes, survey questions were designed to be compatible with, but more focused than, those of a survey conducted …

Putting The Wind At Our Backs: Assessing U.S. Potential For 20% Wind Energy By 2030, Kevin T. Harnett

Honors Theses

The discussion surrounding the future of energy, particularly in the United States, has gained significant momentum in recent years for an obvious reason — it’s daunting. Our dependence on fossil fuels has positioned our nation in an undesirable predicament with a questionable future. With the associated consequences, principally Climate Change, it is essential that energy be addressed as a primary national concern. Renewables need to flip the switch.

Modeling Biofuel Production In Southern Pine Forests: The Effects On Soil Properties, Brittany L. Oakes

Honors Theses

From consuming energy alone in 2009, the United States ranked second as a carbon emitter at 5,425 million metric tons annually; China was the leader at 7,706 million metric tons and India placed third at 1,591 million metric tons (EIA, 2010). Yet in 2009, the U.S. consumed more electricity than both China and India and was the leading importer of electricity (EIA, 2010). Incorporating more domestic sources of renewable energy can simultaneously alleviate two issues: mitigating climate change catastrophes and significantly reduce our dependence on foreign markets for electricity and other forms of energy. Additionally, evidence of dwindling international oil …

The Carbon Budget Impact Of Sagebrush Degradation, Andrew Connor Austreng

Boise State University Theses and Dissertations

More than 20,000 km2 of sagebrush (Artemesia spp.) ecosystems within the Great Basin have been replaced, often following wildfire, by the nonnative winter annual cheatgrass (Bromus tectorum). At a field site in the central Snake River Plain of southern Idaho, the impact of this invasion on the soil carbon (C) reservoir has been evaluated and the potential soil C benefits of bunchgrass (Agropyron cristatum) seeding was assessed. Using a large soil C dataset (n = 850), differences in total organic carbon and root biomass were quantified in immediately-adjacent sagebrush, cheatgrass, and bunchgrass communities. Statistical …

Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock

Graduate Theses and Dissertations

Graphene, what some are terming the "new silicon", has the possibility of revolutionizing technology through nanoscale design processes. Fabrication of graphene for device processing is limited largely by the temperatures used in conventional deposition. High temperatures are detrimental to device design where many different materials may be present. For this reason, graphene synthesis at low temperatures using plasma-enhanced chemical vapor deposition is the subject of much research. In this thesis, a tool for ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV-PECVD) and accompanying subsystems, such as control systems and alarms, are designed and implemented to be used in future graphene growths. …

Variability Of Black Carbon Deposition To The East Antarctic Plateau, 1800-2000 Ad, M. M. Bisiaux, R. Edwards, J. R. Mcconnell, M. R. Albert

Dartmouth Scholarship

Refractory black carbon aerosols (rBC) from biomass burning and fossil fuel combustion are deposited to the Antarctic ice sheet and preserve a history of emissions and long-range transport from low- and mid-latitudes. Antarctic ice core rBC records may thus provide information with respect to past combustion aerosol emissions and atmospheric circulation. Here, we present six East Antarctic ice core records of rBC concentrations and fluxes covering the last two centuries with approximately annual resolution (cal. yr. 1800 to 2000). The ice cores were drilled in disparate regions of the high East Antarctic ice sheet, at different elevations and net snow …

Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce

College of Arts and Sciences Poster Presentations

Soil carbon is the third largest carbon pool within the global carbon cycle; however, soil carbon amounts are not well quantified, and exchange rates of soil carbon are not well understood. Soil carbon can be divided into organic carbon and inorganic carbon, where inorganic carbon (pedogenic carbonate) is precipitated during soil formation and accumulates over time in semi-arid and arid environments. Calcic soils within the semiarid regions of the Boise Valley result from active pedogenic accumulation of secondary CaCO₃ resulting in prominent 'caliche' layers in soils formed on many of the Boise River terraces. The larger goals of this …

Feeding Habitats Of The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi, In The Suwannee And Yellow Rivers, Florida, As Identified By Multiple Stable Isotope Analyses, Kenneth J. Sulak, J. J. Berg, M. Randall

United States Geological Survey: Staff Publications

Stable ¹³C, ¹⁵N, and ³⁴S isotopes were analyzed to define the feeding habitats of Acipenser oxyrinchus desotoi in the Suwannee and Yellow River populations. For the majority (93.9%) of Suwannee sub adults and adults, 13C and 34S signatures indicate use of nearshore marine waters as primary winter feeding habitat, probably due to the limiting size of the Suwannee Sound estuary. In the Yellow River population, 13C isotope signatures indicate that adults remain primarily within Pensacola Bay estuary to feed in winter, rather than immigrating to the open Gulf of Mexico. A minor Suwannee River subset (6% of …

An Investigation Of Voluntary Corporate Greenhouse Gas Emissions Reporting In A Market Governance System: Australian Evidence, Michaela Rankin, Carolyn Windsor, Dina Wahyuni

Carolyn Windsor

Purpose – Institutional governance theory is used to explain voluntary corporate greenhouse gas (GHG) reporting in the context of a market governance system in the absence of climate change public policy. This paper seeks to hypothesise that GHG reporting is related to internal organisation systems, external privately promulgated guidance and EU ETS trading.

Design/methodology/approach – A two-stage approach is used. The initial model examines whether firms’ GHG disclosures are associated with internal organisation systems factors: environmental management systems (EMS), corporate governance quality and environmental management committees as well as external private guidance provided by the Global Reporting Initiative (GRI) and …

Interannual And Spatial Impacts Of Phenological Transitions, Growing Season Length, And Spring And Autumn Temperatures On Carbon Sequestration: A North America Flux Data Synthesis, Chaoyang Wu, Alemu Gonsamo, Jing Ming Chen, Werner A. Kurz, David T. Price, Peter M. Lafleur, Rachhpal S. Jassal, Danilo Dragoni, Gil Bohrer, Christopher M. Gough, Shashi B. Verma, Andrew E. Suyker, J. William Munger

School of Natural Resources: Faculty Publications

Understanding feedbacks of ecosystem carbon sequestration to climate change is an urgent step in developing future ecosystem models. Using 187 site-years of flux data observed at 24 sites covering three plant functional types (i.e. evergreen forests (EF), deciduous forests (DF) and non-forest ecosystems (NF) (e.g., crop, grassland, wetland)) in North America, we present an analysis of both interannual and spatial relationships between annual net ecosystem production (NEP) and phenological indicators, including the flux-based carbon uptake period (CUP) and its transitions, degree-day-derived growing season length (GSL), and spring and autumn temperatures. Diverse responses were acquired between annul NEP and these indicators …

The Density Factor In The Synthesis Of Carbon Nanotube Forest By Injection Chemical Vapor Deposition, R. W. Call, C. G. Read, C. Mart, T. -C. Shen

T. -C. Shen

Beneath the seeming straight-forwardness of growing carbon nanotube(CNT) forests by the injection chemical vapor deposition(CVD) method, control of the forest morphology on various substrates is yet to be achieved. Using ferrocene dissolved in xylene as the precursor, we demonstrate that the concentration of ferrocene and the injection rate of the precursor dictate the CNT density of these forests. However, CNT density will also be affected by the substrates and the growth temperature which determine the diffusion of the catalyst adatoms. The CNT growth rate is controlled by the temperature and chemical composition of the gases in the CVD reactor. We …

Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou

Australian Institute for Innovative Materials - Papers

Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be the most effective dopant to enhance high-field properties. However, the critical role of carbon remains elusive, and also low-field critical current density has not been improved. Here, we have undertaken malic acid doping of MgB2 and find that the microscopic origin for the enhancement of high-field properties is due to boron vacancies and associated stacking faults, as observed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. The carbon from the malic acid almost uniformly encapsulates …

Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler

Australian Institute for Innovative Materials - Papers

Free-standingsingle-walledcarbonnanotube/SnO₂ (SWCNT/SnO₂) anodepaper was prepared by vacuum filtration of SWCNT/SnO₂ hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, in which ultra-fine SnO₂ nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately as groups of nanoparticles on the surfaces of singlewalled CNT bundles. Electrochemical measurements demonstrated that the anodepaper with 34 wt.% SnO₂ had excellent cyclic retention, with the high specific capacity of 454 mAh g⁻¹ beyond 100 cycles at a current …

Ch4, Co, And H2o Spectroscopy For The Sentinel-5 Precursor Mission: An Assessment With The Total Carbon Column Observing Network Measurements, A Galli, A Butz, R A. Scheepmaker, O Hasekamp, J Landgraf, P Tol, D Wunch, N M. Deutscher, G C. Toon, P O. Wennberg, D W. T Griffith, I Aben

Faculty of Science - Papers (Archive)

The TROPOspheric Monitoring Instrument (TROPOMI) will be part of ESA’s Sentinel-5 Precursor (S5P) satellite platform scheduled for launch in 2015. TROPOMI will monitor methane and carbon monoxide concentrations in the Earth’s atmosphere by measuring spectra of back-scattered sunlight in the short-wave infrared (SWIR).

Atmospheric Carbon Dioxide Retrieved From The Greenhouse Gases Observing Satellite (Gosat): Comparison With Ground-Based Tccon Observations And Geos-Chem Model Calculations, A Cogan, H Boesch, R Parker, L Feng, Paul Palmer, J-F Blavier, Nicholas M. Deutscher, Ronald Macatangay, Justus Notholt, C M. Roehl, Thorsten Warneke, Debra Wunch

Faculty of Science - Papers (Archive)

We retrieved column-averaged dry air mole fractions of atmospheric carbon dioxide (XCO 2) from backscattered short-wave infrared (SWIR) sunlight measured by the Japanese Greenhouse gases Observing SATellite (GOSAT). Over two years of XCO 2 retrieved from GOSAT is compared with XCO 2 inferred from collocated SWIR measurements by seven ground-based Total Carbon Column Observing Network (TCCON) stations. The average difference between GOSAT and TCCON XCO 2 for individual TCCON sites ranges from -0.87 ppm to 0.77 ppm with a mean value of 0.1 ppm and standard deviation of 0.56 ppm. We find an average bias between all GOSAT and TCCON …

The Biogeochemistry Of Carbon Isotopes In Local Lakes, Stephen Edward Sadurski

Browse all Theses and Dissertations

Photosynthesis, respiration, and decay of organic matter all involve the transfer of carbon among the carbon-bearing species in the systems. These biogeochemical processes also fractionate the carbon isotope composition, which results in changes to the carbon isotope composition of the dissolved inorganic carbon (DIC) pool. This thesis presents two separate, but related studies regarding the influence of biogeochemical processes on carbon isotopes in local lakes. Crystal Lake is a small but deep glacial lake (12.5 acres, 11.9 meters). The study shows that during thermal stratification, the heaviest carbon can be found in the epilimnion near the surface, where photosynthesis dominates …

Enhanced Hydrogen Storage Properties Of Naalh4 Co-Catalysed With Niobium Fluoride And Single-Walled Carbon Nanotubes, Jianfeng Mao, Zaiping Guo, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

The effects of single-walled carbon nanotubes (SWCNTs) as a co-catalyst with NbF₅ on the dehydrogenation and hydrogenation kinetics of NaAlH₄ were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, differential thermal analysis, temperature-programmed desorption, and isothermal hydrogen ab/desorption techniques. It has been revealed that there is a synergistic effect of SWCNTs and NbF₅ on the de/rehydrogenation of NaAlH4, which improves the hydrogen de/absorption performance when compared to adding either SWCNTs or NbF₅ alone. For example, the apparent activation energy for the first-step and the second-step dehydrogenation of the co-doped NaAlH4 sample is estimated to be 85.9 …

Irradiation Si On Carbon Nanotube Paper As A Flexible Anode Material For Lithium-Ion Batteries, Shulei Chou, Mihail Ionescu, Jia-Zhao Wang, Brad Winton, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Silicon single walled carbon nanotube composite paper was modified by low energy ion implantation using 5i to obtain a flexible composite paper. Raman and FE-SEM results show that structure of SWCNT could be destroyed by the implantation. Electrochemical measurements display that the implanted SI can improve the specific capacity and the reversible capacity of CNT paper. After 50 cycles, the specific capacity of 5Hmplanted CNT paper is 30 per cent higher than the pristine CNT.

Conducting Composite Materials From The Biopolymer Kappa-Carrageenan And Carbon Nanotubes, Ali Aldalbahi, Jin Chu, Peter Feng, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

Conducting composite films containing carbon nanotubes (CNTs) were prepared by using the biopolymer kappa-carrageenan (KC) as a dispersant. Rheological studies indicated that 0.5% w/v was the appropriate KC concentration for dispersing CNTs. Our results showed that multiwalled nanotubes (MWNTs) required less sonic energy than single-walled nanotubes (SWNTs) for the dispersion process to be complete. Films prepared by vacuum filtration exhibited higher conductivity and improved mechanical characteristics compared to those prepared by evaporative casting. All composite films displayed sensitivity to water vapour, but MWNT films were more sensitive than SWNT films.