Digital Commons Network^™

Damage Tolerance Of Buckling-Critical Unidirectional Carbon, Glass,And Basalt Fiber Composites In Co-Cured Aramid Sleeves, Michael D. Embley

Theses and Dissertations

Compression strength after impact tests were conducted on unidirectional composite rods with sleeves. These elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies). The unidirectional cores composed of carbon, glass, or basalt fiber/epoxy composites were co-cured in aramid sleeves. Sleeve patterns included both bi-directional (unsymmetric) braids and unidirectional spiral wraps with sleeve coverage ranging from nominally half to full. The diameters were nominally 8 and 11 mm (5/16 and 7/16 in). The larger diameter had nominally twice the cross-sectional area, to quantify the effects of scaling. The specimens were long enough to …

Factors Controlling Dissolved Organic Carbon Lability And Ecological Fate In The East Branch Swift River, Massachusettes, Hall Eric

Theses and Dissertations

Fluvial systems have been estimated to transform, transport, or store 2.75 petagrams (Pg) of Organic Carbon (OC) per year. Although approximately 1Pg per year of terrestrial carbon is fluxed to the atmosphere through inland waters, little is known about the factors regulating its eventual ecological fate. 28 day lability incubations were conducted concurrent with the measurement of several environmental parameters including discharge, nutrient concentration, DO13C, and DOC:DON at several sites along Bigelow Brook and the East Branch of the Swift River, Massachusetts. Temporal and spatial variation of DOC, DOC:DON and DO13C were explored. Two distinct DOC consumption rates, short and …

Towards Novel Entangled Carbon Nanotube Composite Electrodes, Gordon G. Wallace, P. Sherrell, J. Chen, A. Minett

Gordon Wallace

The commercialization of carbon nanotube electrodes is impeded by the lack of bulk processing techniques. One approach to overcome this impediment is the growth of macroscopic CNT composite architectures which do not require any extra processing. Unfortunately the fundamental growth mechanisms of these carbon composites is not currently understood. To probe this mechanism a systematic examination of the effect of certain growth parameters was undertaken. Within this paper we present the promising preliminary findings of this study revealing extremely complex relationships between variables during growth. We also present the performance of the produced architectures as capacitor electrodes and the further …

Requirements For A Renewables Revolution, Felix Mormann

Faculty Scholarship

This Article identifies and analyzes the obstacles presently barring the rise of renewables, evaluates the role of the current policy favorite emission pricing, and offers design recommendations for a comprehensive U.S. renewables policy.

Successful climate change mitigation requires a timely shift to renewable sources of energy, such as sunlight, wind or tides, to decarbonize today’s high-carbon electricity sector. But market pull alone is not strong enough. This Article discusses the most widely cited economic barriers and identifies and evaluates additional obstacles related to the electricity sector’s regulatory framework.

Emission pricing is largely considered the most efficient policy to drive the …

Biological And Ecological Responses To Carbon-Based Nanomaterials, Tatsiana Ratnikova

All Dissertations

Nanotechnology has been undergoing tremendous development in recent decades, driven by realized perceived applications of nanomaterials in electronics, therapeutics, imaging, sensing, environmental remediation, and consumer products. Along with these developments there have been increased evidences that engineered nanomaterials are often associated with hazardous effects they invoke in biological and ecosystems through intentional designs or unintentional discharge. Consequently there is a crucial need for documenting and understanding the interactions between nanoparticles and biological and ecosystems. This dissertation is aimed at bridging such a knowledge gap by examining the biological and ecological responses to carbon nanoparticles, a major class of nanomaterials which …

Determination Of Freshwater Algal Biomass And Sulfolipid Content As Functions Of Inorganic Carbon Treatment, Melissa Morella

All Theses

Cultures of mixed freshwater algae were grown in open batch reactors made up of modified BG-11 media that contained 0, 25, 50 or 100% of the suggested inorganic carbon content (0, 0.5, 0.1 and 0.2 g/L Na₂CO₃) to assess the subsequent production of the high-value product, sulfoquinovosyl diacylglycerol (SQDG). After 25 days of growth, the reactors were composed of primarily Oscillatoria growth. All four reactors exhibited a trend of increasing biomass and alkalinity with time, and an initial increase then decrease in pH. The total inorganic carbon (TIC) in all reactors exhibited a mirrored, opposite trend …

Risks Posed To Drinking Water Aquifers Due To Leakage Of Dissolved Co2 In Improperly Abandoned Wellbores, Kirk Ellison

All Theses

In order to ensure safe long-term storage of carbon dioxide in geologic formations, the risks posed by improperly abandoned wells must be understood and minimalized. In addition to supercritical and gaseous CO2, brine containing dissolved CO2 poses a leakage risk. CO2 dissolution in brine leads to denser brine and better long-term storage security, but its leakage risk is not zero. Under specific circumstances with formation overpressure or overlying aquifer drawdown, dissolved brine can flow up improperly abandoned wells where it can potentially enter and contaminate drinking water aquifers. The possibility that depressurization in the wellbore may cause CO2 exsolution from …

Equilibrium Speciation Of Select Lanthanides In The Presence Of Acidic Ligands In Homo- And Heterogeneous Solutions, Troy Robinson

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation explores lanthanide speciation in liquid solution systems related to separation schemes involving the acidic ligands: bis(2-ethylhexyl) phosphoric acid (HDEHP), lactate, and 8-hydroxyquinoline. Equilibrium speciation of neodymium (Nd³⁺ ), sodium (Na⁺ ), HDEHP, water, and lactate in the TALSPEAK liquid-liquid extraction system was explored under varied Nd³⁺ loading of HDEHP in the organic phase and through extraction from aqueous HCl and lactate media. System speciation was probed through vapor pressure osmometry, visible and Fourier Transform Infrared (FTIR) spectroscopy, ²² Na and ¹³ C labeled lactate radiotracer distribution measurements, Karl Fischer titrations, and equilibrium pH measurements. Distribution …

Slides: Long-Term Augmentation Of The Water Supply Of The Colorado River System, Les Lampe

Navigating the Future of the Colorado River (Martz Summer Conference, June 8-10)

Presenter: Les Lampe, Colorado River Water Consultants, Las Vegas, Nevada

29 slides

Investigation Of Electrical Transport In Hydrogenated Multiwalled Carbon Nanotubes, Adam L. Friedman, Hyunkyung Chun, Don Heiman, Yung Joon Jung, Latika Menon

Yung Joon Jung

Highly disordered multiwalled carbon nanotubes of large outer diameter (~60 nm) fabricated by means of chemical vapor deposition process inside porous alumina templates exhibit ferromagnetism when annealed in a H2/Ar atmosphere. In the presence of an applied magnetic field, there is a transition from positive to negative magnetoresistance. The transition may be explained in terms of the Bright model for ordered and disordered carbon structures. Additionally, temperature dependent electrical transport experiments exhibit a zero-bias anomaly at low temperature.

Method For Hydraulically Separating Carbon And Classifying Coal Combustion Ash, Thomas L. Robl, John Groppo

Center for Applied Energy Research Faculty Patents

A method for selective separation of particles from a particle-containing material includes preparing a slurry of the particle-containing material and a dispersant, passing the slurry through a hydraulic classifier in a first direction, establishing a particle flow in a direction that is different from the first direction, and recovering particles having a mean particle size of about 2-7 μm. The flow of particles defines a cross-current flow relative to the slurry feed direction. The method further includes providing the classifier with an interior divider assembly defining at least one inclined channel. The divider assembly typically includes a plurality of substantially …

Woodland Expansion's Influence On Belowground Carbon And Nitrogen In The Great Basin U.S., Benjamin M. Rau, Dale W. Johnson, Robert R. Blank, Robin J. Tausch, Bruce A. Roundy, Richard F. Miller, Todd G. Caldwell, Annmarie Lucchesi

Articles

Vegetation changes associated with climate shifts and anthropogenic disturbance can have major impacts on biogeochemical cycling and soils. Much of the Great Basin, U.S. is currently dominated by sagebrush (Artemisia tridentate (Rydb.) Boivin) ecosystems. Sagebrush ecosystems are increasingly influenced by pinyon (Pinus monophylla Torr. & Frém and Pinus edulis Engelm.) and juniper (Juniperus osteosperma Torr. and Juniperus occidentalis Hook.) expansion. Some scientists and policy makers believe that increasing woodland cover in the intermountain western U.S. offers the possibility of increased organic carbon (OC) storage on the landscape; however, little is currently known about the distribution of OC …

Molecular Beam Epitaxy Approach To The Graphitization Of Gaas(100) Surfaces, Paul J. Simmonds, John Simon, Jerry M. Woodall, Minjoo Larry Lee

Paul J. Simmonds

The authors present a method for obtaining graphitized carbon on GaAs(100) surfaces. Carbon-doped GaAs is grown by molecular beam epitaxy before controlled thermal etching within the growth chamber. An AlAs layer beneath the carbon-doped GaAs acts as a thermal etch stop. As the GaAs is etched away, the carbondopant atoms remain on the surface due to their low vapor pressure. The total number of carbon atoms available is precisely controllable by the doping density and thickness of the carbon-doped GaAs layer. Characteristic phonon modes in Raman spectra from the thermally etchedsurfaces show that the residual surfacecarbon atoms form sp^{2 …}

Carbon And Sulfur Cycling In Early Paleozoic Oceans, Cara Kim Thompson

Doctoral Dissertations

Here, I evaluate biospheric evolution during the Ordovician using high-resolution inorganic carbon and sulfur (carbonate-associated sulfate and pyrite) isotope profiles for Early Ordovician to early Late Ordovician strata from geographically distant sections in Western Newfoundland and the Argentine Precordillera. Additionally, I present new, high-resolution U-Pb ages for volcanic ash beds within strata of the Argentine Precordillera. Carbon isotope data record subdued variation that is typical of Early- to Middle Ordovician strata worldwide. By contrast, sulfur-isotopic compositions of carbonate-associated sulfate reveal a complex signal of short-term, rhythmic variation superimposed over a longer-term signal. This short-term, rhythmic variation occurs in all sections …

A Study Of Carbon Features In Type Ia Supernova Spectra, Jerod T. Parrent, R. C. Thomas, Robert A. Fesen, G. H. Marion

Dartmouth Scholarship

One of the major differences between various explosion scenarios of Type Ia supernovae (SNe Ia) is the remaining amount of unburned (C+O) material and its velocity distribution within the expanding ejecta. While oxygen absorption features are not uncommon in the spectra of SNe Ia before maximum light, the presence of strong carbon absorption has been reported only in a minority of objects, typically during the pre-maximum phase. The reported low frequency of carbon detections may be due to low signal-to-noise data, low abundance of unburned material, line blending between C II 6580 and Si II 6355, ejecta temperature differences, asymmetrical …

Forest Carbon Mapping And Spatial Uncertainty Analysis: Combining National Forest Inventory Data And Landsat Tm Images, Andrew Lawrence Fleming

Theses

Being able to accurately map forest carbon is a critical step in the global carbon cycle modeling and management process. This project is aimed at enhancing the current methodologies used for forest carbon mapping, and applying a method to account for any errors produced. By doing so, more accurate decisions can be made based on the knowledge gained from forest carbon maps; such as policy decisions on how to manage forests, or how to mitigate climate change. The use of remotely sensed images, in combination with Forest Inventory and Analysis (FIA) data, is one such way of doing this. This …

The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner

Theses and Dissertations

Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a …

Revisiting Soil C And N Sampling: Quantitative Pits Vs. Rotary Cores, Benjamin M. Rau, April M. Melvin, Dale W. Johnson, Christine L. Goodale, Robert R. Blank, Guinevere Fredriksen, Watkins W. Miller, James D. Murphy, Donald E. Todd Jr., Roger F. Walker

Articles

Increasing atmospheric carbon dioxide and its feedbacks with global climate have sparked renewed interest in quantifying ecosystem carbon (C) budgets, including quantifying belowground pools. Belowground nutrient budgets require accurate estimates of soil mass, coarse fragment content, and nutrient concentrations. It has long been thought that the most accurate measurement of soil mass and coarse fragment content has come from excavating quantitative soil pits. However, this methodology is labor intensive and time consuming. We propose that diamond-tipped rotary cores are an acceptable if not superior alternative to quantitative soil pits for the measurement of soil mass, coarse fragment content, C and …

Changes To Electrical Conductivity In Irradiated Carbon Nanocomposites, Nickolas A. Duncan

Theses and Dissertations

Carbon nanotubes (CNT) and carbon nanofibers (CNF) are two nanoparticles incorporated in a polymer to create a composite material. These composites are two potential lightweight materials for use as replacements for aluminum structures on satellite systems. Both composite materials have a low resistivity that is consistent with conductive materials. However, the CNT composite is substantially more conductive than the CNF composite. The CNT and CNF composites were irradiated with electrons and neutrons to fluence levels of and. No changes were observed in the resistivity of the CNF composites following neutron and electron irradiation. A 3.7% increase in resistivity was observed …

Crop Updates 2011 - Farming Systems, Janette Drew, Rob Grima, Bob French, Raj Malik, Mark Seymour, Christine Zaicou-Kunesch, Glenn Mcdonald, Brendon Nicholas, Dennis Van Gool, James Fisher, Peter Tozer, Doug Abrecht, Michael Robertson, Cameron Weeks, Michael O'Conner, Peter Newman, Mike Clarke, Andrew Blake, Gordon Macaulay, Vijay Jayasena, Syed M. Nasar-Abbas, Larisa Cato, Robert Loughman, Ken Quail

Crop Updates

This session covers twelve papers from different authors:

1. Fallowing 50% of the farm each year – does it pay? Janette Drew and Rob Grima

Department of Agriculture and Food

2. How crop sequences affect the productivity and resilience of cropping systems in two Western Australian environments, Bob French, Raj Malik, Mark Seymour, Department of Agriculture and Food

3. When is continuous wheat or barley sustainable? Christine Zaicou-Kunesch and Rob Grima Department of Agriculture and Food

4. Identifying constraints to bridging the yield gap, Glenn McDonald, Department of Agriculture and Food

5. Land constraints limiting wheat yields in …

Graphitized Carbon On Gaas(100) Substrates, J. Simon, P. J. Simmonds, J. M. Woodall, M. L. Lee

Paul J. Simmonds

We report on the formation of graphitized carbon on GaAs(100) surfaces by molecular beam epitaxy. We grew highly carbon-doped GaAs on AlAs, which was then thermally etched in situ leaving behind carbon atoms on the surface. After thermal etching, Raman spectra revealed characteristic phonon modes for sp²-bonded carbon, consistent with the formation of graphitic crystallites. We estimate that the graphitic crystallites are 1.5–3 nm in size and demonstrate that crystallite domain size can be increased through the use of higher etch temperatures.

Nanoscale Carbon Architectures For Electrode Applications, Stephen Wakeland

Mechanical Engineering ETDs

Two primary objectives were the basis of this research. The first objective was to synthesize a variety of carbonaceous nanomaterials using plasma torch and furnace-based expansion-reduction techniques. The second objective was to correlate the unique characteristics of these materials to their electrical properties when assembled into electrochemical double-layered capacitors (EDLCs), or supercapacitors. A microwave atmospheric plasma torch was used to produce graphene and diverse graphitic and amorphous carbon nanomaterials. Direct high-temperature conversion under an argon plasma atmosphere of various hydrocarbons, in solid, liquid, and gaseous states, yielded carbon nanoparticles, nanoparticle/sheet mixtures, and graphene respectively. Graphene was also produced using a …

Carbon Coating For Improved Hydrothermal Stability Of Silica Supports, Amanda Lynn Staker

Nanoscience and Microsystems ETDs

A large number of industrial chemicals produced today come from petroleum-based feedstocks. With these feedstocks dwindling, it is necessary to develop alternative ways to produce these chemicals from biorenewable feedstocks. The move from the current petroleum-based chemical industry to a biorenewable chemical industry will build on a current platform chemical approach, where a small number of key chemical intermediates produced from biorenewable sources will serve as the platform to produce a broad range of chemical products. Since carbon is necessary to produce these chemicals, biomass, with its short formation time, must become the feedstock for the chemical industry. Since the …

A Survey Of Oxidative Paracatalytic Reactions Catalyzed By Enzymes That Generate Carbanionic Intermediates: Implications For Ros Production, Cancer Etiology, And Neurodegenerative Diseases, Victoria Bunik, John Schloss, John T. Pinto, Natalia Dudareva, Arthur J L Cooper

NYMC Faculty Publications

Enzymes that generate carbanionic intermediates often catalyze paracatalytic reactions with O2 and other electrophiles not considered “normal” reactants. For example, pyridoxal 5′-phosphate (PLP)—containing pig kidney dopa decarboxylase oxidizes dopamine with molecular O2 to 3,4-dihydroxyphenylacetaldehyde at about 1% of the rate at which it catalyzes nonoxidative dopa decarboxylation. The mutant Y332F enzyme, however, catalyzes stoichiometric conversion of dopa to 3,4-dihydroxyphenylacetaldehyde, suggesting that even minor structural changes may alter or initiate paracatalytic reactions catalyzed by certain enzymes. Carbanions generated by several thiamine diphosphate (ThDP)—dependent enzymes react with different electrophiles, transforming some xenobiotics and endogenous compounds into potentially biologically hazardous products. The detrimental …

Radiative Forcing Of Natural Forest Disturbances, Thomas L. O'Halloran, Beverly E. Law, Michael L. Goulden, Zhuosen Wang, Jordan G. Barr, Crystal Schaaf, Mathew Brown, José D. Fuentes, Mathias Göckede, Andrew Black, Vic Engel

FCE LTER Journal Articles

Forest disturbances are major sources of carbon dioxide to the atmosphere, and therefore impact global climate. Biogeophysical attributes, such as surface albedo (reflectivity), further control the climate-regulating properties of forests. Using both tower-based and remotely sensed data sets, we show that natural disturbances from wildfire, beetle outbreaks, and hurricane wind throw can significantly alter surface albedo, and the associated radiative forcing either offsets or enhances the CO₂ forcing caused by reducing ecosystem carbon sequestration over multiple years. In the examined cases, the radiative forcing from albedo change is on the same order of magnitude as the CO₂ forcing. …

Dermal Reduction Of Urushiols Using An Activated Charcoal Formulated Dermal Care Patch, Celena Cameron

Honors Theses

For centuries, activated Charcoal (AC) has been used externally in a poultice form to adsorb "poisons" trapped in the outer layers of skin and internally to relieve intestinal discomfort and to remove toxic materials. The largest use for activated charcoal, in our society, is as a filter bed in air and water remediation cartridges. Recently, scientists have formulated AC into a nonstick dermal bandage called the Charcoal Patch (CP), but the adsorption properties are not well understood for this new formulation. Experiments have been conducted to see if these dermal bandages can be used to adsorb oils such as poison …

Forest Structure And Aboveground Biomass In The Southwestern United States From Modis And Misr, Mark Chopping, Crystal B. Schaaf, Feng Zhao, Anne W. Nolin, Gretchen G. Moisen, John V. Martonchik, Michael Bull

United States National Aeronautics and Space Administration: Publications

Red band bidirectional reflectance factor data from the NASA MODerate resolution Imaging Spectroradiometer (MODIS) acquired over the southwestern United States were interpreted through a simple geometric–optical (GO) canopy reflectance model to provide maps of fractional crown cover (dimensionless), mean canopy height (m), and aboveground woody biomass (Mg ha⁻¹) on a 250 m grid. Model adjustment was performed after dynamic injection of a background contribution predicted via the kernel weights of a bidirectional reflectance distribution function (BRDF) model. Accuracy was assessed with respect to similar maps obtained with data from the NASA Multiangle Imaging Spectroradiometer (MISR) and to contemporaneous …

A Proposed Methodology For Predicting The Carbon And Nitrogen Stable Isotope Measures Of K'Inich Yax K'Uk Mo', Copan Dynastic Founder, Keith Edwards

Electronic Theses and Dissertations

The purpose of this thesis is to show that stable isotope analysis can be used to predict K’inich Yax K’uk Mo’s stable isotope measures based on Stuart’s (2007) hypothesis that K’inich Yax K’uk Mo’, the dynastic founder of the Copan royal lineage, was a Caracol lord. There is significant and convincing evidence that K’inich Yak K’uk Mo’ had a non-Copanec origin. Stable isotope analysis is a tested and reliable method for detailing diets and migratory paths of ancient humans and this theory is applied as a predictor of the stable isotope measures of K’inich Yax K’uk Mo’, if he did …

Improving The Adsorption Of Heavy Metals From Water Using Commercial Carbons Modified With Egg Shell Wastes, Alejandro Guijarro-Aldaco, Virginia Hernandez-Montoya, Adrian Bonilla-Petriciolet, Miguel A. Montes-Moran, Didilia I. Mendoza-Castillo

Adrian Bonilla-Petriciolet

We introduce the application of hen egg shell waste to improve the adsorption capacities of heavy-metal ions using commercial carbons via the modification of their surface chemistry. Specifically, a calcium solution extracted from egg shell waste has been used as a low-cost activation agent to improve the adsorption properties of three commercial carbons. An orthogonal array of the Taguchi method has been applied to identify the optimal conditions for the adsorbent modification process using the Zn batch adsorption, at 30 °C and pH 5, as the response variable. Our results show that maximum adsorption capacities of Cd, Ni, and Zn …

The Ethics Of Carbon Neutrality: A Critical Examination Of Voluntary Carbon Offset Providers, K. Kathy Dhanda, Laura Hartman

Laura Hartman

In this paper, we explore the world’s response to the increasing impact of carbon emissions on the sobering threat posed by global warming: the carbon offset market. Though the market is a relatively new one, it has quickly spawned countless offset providers under both regulated and voluntary regimes. Due to the naïveté of some stakeholders who participate in the market surrounding its rather technical aspects, no common quality or certification structure has emerged for providers. In fact, there are claims to the contrary, that a somewhat ‘cowboy’ atmosphere exists, and that there are “widespread instances of people and organizations buying …