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Dissertations / Theses on the topic 'Carbon composition'

Author: Grafiati

Published: 4 June 2021

Last updated: 4 February 2022

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1

Lal, Archit. "Effect of gas composition and carbon activity on the growth of carbon nanotubes." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001151.

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2

Nel, Jacques A. "Vegetation and microbial determinants of soil carbon isotopic composition." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28072.

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Typically, soil δ¹³C and δ¹⁵N values tend to increase with depth across a wide range of ecosystems. Changes in δ¹³C with depth have been attributed to vegetation changes (i.e. C₃/C₄ shifts), but the similarity in δ¹³C and δ¹⁵N profiles suggest that microbial decomposition may play an important role. The determinants of soil δ¹³C and δ¹⁵N, however, are complex and microbial decomposition and vegetation shifts are not the only mechanisms that drive the fractionation of the isotopes with depth. We explored the utility of using δ¹³C as a proxy for vegetation change by considering alternative mecha

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3

Moody, Catherine Sarah. "The fate and composition of in-stream organic carbon." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10854/.

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The northern peatlands cover only 3% of the Earth, and store between 20 and 30% of the terrestrial carbon pool. In the UK, 15% of the land is covered in peatland, which is estimated to store 2.3 Pg of carbon. Recently, a trend of increasing DOC concentrations in surface waters has been observed in the northern hemisphere, and the in-stream processing and degradation of DOC to CO2 could represent a major and increasing source of greenhouse gas to the atmosphere. This thesis measured net DOC loss in unfiltered river water samples across different catchment scales, ranging from 0.005 to 1086 km2,

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4

Barral, Cuesta Abel. "The carbon isotope composition of the fossil conifer Frenelopsis as a proxy for reconstructing Cretaceous atmospheric CO2." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1148.

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Le Crétacé a été une période d'instabilité climatique et du cycle du carbone, dont le CO2 atmosphérique a été désigné comme le driver majeur. Cependant, les reconstitutions du CO2 atmosphérique ne reflètent ni les dynamiques climatiques ni les grands évènements de perturbation du cycle du carbone décrits pour cette période. J'ai utilisé la composition isotopique de carbone de la plante fossile Frenelopsis (d13Cleaf) comme un nouvel proxy pour reconstituer le CO2 atmosphérique du Crétacé en termes de composition isotopique de carbone (d13CCO2) et de concentration (pCO2). La première courbe de d

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5

Buckingham, Sarah. "Dissolved Organic Carbon In Topsoils : Concentration,Flux and Isotopic Composition." Thesis, Lancaster University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531683.

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6

Dinc, Fatma. "Chemical composition and oxidation study of nitrogen doped carbon nanotubes." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:a461f5d5-a07b-41d0-a044-8e83448fd97e.

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In this work, carbon nanotubes (CNTs) and nitrogen doped carbon nanotubes (N-CNTs) were synthesized by aerosol chemical vapour deposition and the synthesis parameters such as temperature, catalyst concentration, precursor concentration, gas flow rate and reaction time were studied. N incorporation was extensively investigated on the basis of N bonding configurations detected by X-ray photoelectron spectroscopy (XPS), N concentration distribution measured by electron energy loss spectroscopy (EELS) and N spatial distribution by aberration corrected scanning transmission electron microscopy coup

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7

Akeer, Emad S. "Effect of Carbon Steel Composition and Microstructure on CO2 Corrosion." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1399315460.

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8

Chonde, Daniel Burje. "Spirometer techniques for measuring molar composition in argon carbon dioxide mixtures." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40905.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.<br>Includes bibliographical references (p. 53-54).<br>This paper examines a new technique for measuring gas composition through the use of a spirometer. A spirometer is high precision pressure transducer which measures the speed of sound in a gas through the emission and reception of ultrasonic pulses, commonly used in medicine to measure patient lung capacity. The spirometer was successfully calibrated to measure gas composition to an accuracy of 1.75% ± 1.23% by ratio by weight. By using a spirometer, the speed of

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9

Yates, Paul David. "The content and stable isotopic composition of carbon in spherical micrometeorites." Thesis, Open University, 1992. http://oro.open.ac.uk/54849/.

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Micrometeorites are extraterrestrial bodies that have survived atmospheric entry to be found on Earth as grains <1mm in diameter. Of the annual flux of extraterrestrial material to the Earth <i>ca</i>.99% is supplied by the micrometeorites. The lifetime of the micrometeroids in the interplanetary medium in extremely ephemeral, but their population is maintained largely by ejection of particles from cometary nuclei and from collisional debris from the asteroid belt. As such, the micrometeorites are of fundemental importance to cosmogony, because they may provide the only means, at present, to d

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10

Shelkov, Denis Alexander. "N and C isotropic composition of different varieties of terrestrial diamonds and carbonado." Thesis, Open University, 1997. http://oro.open.ac.uk/54608/.

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During the course of this research an instrument utilising combustion as a means of gas extraction capable of N, e, Ar and He analysis has been developed and the entire analytical procedure has been automated. N and e isotopic analysis has been performed on eclogitic and peridotitic diamonds (mainly from Yakutian kimberlites and the Roberts Victor kimberlite pipe). Diamonds with unusual (light and heavy relative to the peak of ol3e distribution of mantle diamonds) carbon isotopic signatures were considered for the research so that diamonds in the range of δ¹³C from -30‰ to + 2.8‰ were characte

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11

Lebanna, Joshua. "Composition of supercritical carbon dioxide derived extracts of Chamaemelum nobile / Joshua Lebanna." Thesis, North-West University, 2005. http://hdl.handle.net/10394/588.

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The feasibility of extracting botanical substances from samples of Cameamelum nobile (Roman chamomile) with supercritical carbon dioxide (sc-C02) was investigated. The advantages of clean technology and the relevance of chamomile extracts to the fragrance, flavour, food, cosmetic and pharmaceutical industries sewed as motivation for the investigation. Extractions were performed on selected dried plant material using a commercial laboratory-size supercritical fluid extractor. The extraction conditions (temperature, pressure, time) were optimised in terms of yield of extract using computer-assis

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12

Estes, Emily Racz. "Geochemical controls on the distribution and composition of biogenic and sedimentary carbon." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108904.

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Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>Organic carbon (OC) preserved in marine sediments acts as a reduced carbon sink that balances the global carbon cycle. Understanding the biogeochemical mechanisms underpinning the balance between OC preservation and degradation is thus critical both to quantifying this carbon rese

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13

Koziol, Krystyna A. "The provenance, composition and fate of organic carbon on an Arctic glacier." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/9050/.

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Arctic glaciers are predicted to lose mass rapidly in the next century, leading to the release of organic matter to downstream ecosystems, crucially including nutrients and pollutants. The aim of this study was to collect a comprehensive record of organic carbon (OC) fluxes on a glacier of well-known glaciological characteristics, providing a benchmark example of the biogeochemical impact of glacial melt. Foxfonna, a small Svalbard glacier with net mass losses of -0.74 ± 0.10 m w.e. per annum in the period 1990–2012, represents a rapid melt scenario. The supraglacial OC fluxes associated with

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14

Lindh, Markus. "Role of Different Carbon Sources for Growth, Production and Community Composition of Bacterioplankton." Thesis, University of Kalmar, School of Pure and Applied Natural Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-149.

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<p>It has been suggested that growth, production and community structure of bacterioplankton are dependent on resource availability. However, previous studies have only investigated the effect of either organic substrate mixtures or a few single organic substrates on the bacterioplankton community. The aims of this study were to investigate the impact of five different relevant carbon sources on the bacterioplankton community. This impact was evaluated comparing treatments on samples taken from Skagerrak and the Baltic Sea, in whole seawater cultures. Analysis of bacterial abundance, bacterial

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15

Gromov, Sergey S. [Verfasser]. "Stable isotope composition of atmospheric carbon monoxide : a modelling study / Sergey S. Gromov." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1051305497/34.

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16

Smith, Nafeesah. "Development of capacitive deionisation electrodes: optimization of fabrication methods and composition." University of the Western Cape, 2020. http://hdl.handle.net/11394/7710.

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>Magister Scientiae - MSc<br>Membrane Capacitive Deionisation (MCDI) is a technology used to desalinate water where a potential is applied to an electrode made of carbonaceous materials resulting in ion adsorption. Processes and materials for the production of electrodes to be applied in Membrane Capacitive Deionisation processes were investigated. The optimal electrode composition and synthesis approached was determined through analysis of the salt removal capacity and the rate at which the electrodes absorb and desorb ions. To determine the conductivity of these electrodes, the four point pr

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17

Czuba, Eva. "Development of a technique to study stable carbon isotope composition of NMHCs in ambient air." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ56169.pdf.

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18

Solouki, Bonab Vahab. "Polyurethane (PU) Nanocomposites; Interplay of Composition, Morphology, and Properties." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1542634359353501.

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19

Gaubert, B., H. M. Worden, A. F. J. Arellano, et al. "Chemical Feedback From Decreasing Carbon Monoxide Emissions." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/626068.

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Understanding changes in the burden and growth rate of atmospheric methane (CH4) has been the focus of several recent studies but still lacks scientific consensus. Here we investigate the role of decreasing anthropogenic carbon monoxide (CO) emissions since 2002 on hydroxyl radical (OH) sinks and tropospheric CH4 loss. We quantify this impact by contrasting two model simulations for 2002-2013: (1) a Measurement of the Pollution in the Troposphere (MOPITT) CO reanalysis and (2) a Control-Run without CO assimilation. These simulations are performed with the Community Atmosphere Model with Chemis

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20

Olefeldt, David. "Quantity and composition of waterborne carbon transport in subarctic catchments containing peatlands and permafrost." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103675.

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Both quantity and composition of waterborne transport of dissolved organic carbon (DOC) from peatlands has been hypothesized to be affected by permafrost thaw. Changes in DOC can impact the carbon (C) balance of peatlands directly, but also the carbon balances and metabolism of downstream aquatic environments. In this study I have investigated the DOC export from different peatland types in the Stordalen catchment of northern Sweden (68.20N, 19.03E). The research was performed at various spatial and temporal scales in order to assess the importance of peatland permafrost thaw for both peatlan

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21

Vinten, Phillip A. "Chemical Vapour Deposition Growth of Carbon Nanotube Forests: Kinetics, Morphology, Composition, and Their Mechanisms." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24165.

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This thesis analyzes the chemical vapour deposition (CVD) growth of vertically aligned carbon nanotube (CNT) forests in order to understand how CNT forests grow, why they stop growing, and how to control the properties of the synthesized CNTs. In situ kinetics data of the growth of CNT forests are gathered by in situ optical microscopy. The overall morphology of the forests and the characteristics of the individual CNTs in the forests are investigated using scanning electron microscopy and Raman spectroscopy. The in situ data show that forest growth and termination are activated processes (wit

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22

Thomas, Jean Marie Gruters. "Impact of elevated temperature and carbon dioxide on development and composition of soybean seed." [Gainesville, Fla.] : University of Florida, 2001. http://etd.fcla.edu/etd/uf/2001/anp1055/Impact.pdf.

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Thesis (Ph. D.)--University of Florida, 2001.<br>Title from first page of PDF file. Document formatted into pages; contains xv, 185 p.; also contains graphics. Vita. Includes bibliographical references (p. 168-184).

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23

Ryan, Madeline Faye. "Spatial and Temporal Transitions in the Composition and Transport of Carbon under Variable Flow." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85021.

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Recent studies have focused on dissolved organic matter (DOM) cycling throughout river corridors or in reservoirs, but few have explored DOM cycling in commonplace but understudied run-of-river (ROR) reservoir systems. Impoundments disrupt river flow patterns, as they increase hydraulic residence time and alter the flow of DOM downstream. During storms when the majority of DOM loading occurs, impoundments become less likely to hold DOM and will increase export of DOM downstream. In this study, we quantified DOM bioavailability and composition, carbon flux, and carbon dioxide (CO2) gas evasion

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24

Denis, Marie. "Mécanismes de solubilisation et transfert de matières organiques dissoutes à l'échelle d'un bassin versant agricole : apport de l'étude de la composition moléculaire." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S045/document.

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Les matières organiques dissoutes (MOD), en tant que sources de nutriments ou potentiels vecteurs de pollution, sont impliquées dans de nombreuses problématiques environnementales. Bien qu'elles fassent l'objet de nombreuses études depuis plusieurs décennies, les mécanismes gouvernant leur solubilisation et leur transfert depuis les sols vers les systèmes aquatiques demeurent sujets à discussion. En s'appuyant sur l'étude de la composition moléculaire des MOD par hydrolyse et méthylation assistée par température et couplée à la chromatographie en phase gazeuse et à la spectrométrie de masse (H

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25

Pocztar, Yuri M. "Heat, Light, and Gas Composition Subsystems of a Photo-Bioreactor." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1289934242.

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26

Berry, Stephanie C. Carleton University Dissertation Biology. "The influence of vegetation and soil carbon dioxide exchange on the concentration and isotopic composition of atmospheric carbon dioxide within plant canopies." Ottawa, 1994.

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27

Breithaupt, Joshua L. "Spatio-temporal Dynamics of Soil Composition and Accumulation Rates in Mangrove Wetlands." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6684.

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Coastal wetlands are globally important environments for biogeochemical cycling and are the object of intensive research related to the sequestration and exchange of carbon with oceans, continents, and the atmosphere. Wetland soil core records of organic carbon (OC) provide insights about future ecosystem responses to global change by identifying temporal variability in the context of environmental changes including sea level rise (SLR), anthropogenic reductions in freshwater flow, and landscape-scale disturbance events. My studies of Gulf of Mexico mangroves involved the use of radiometricall

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28

Saavedra, Rios Carolina del Mar. "Etude des carbones durs issus de la biomasse pour l’application dans les batteries Sodium-ion." Thesis, Université Grenoble Alpes, 2020. https://thares.univ-grenoble-alpes.fr/2020GRALI072.pdf.

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La demande croissante en batteries Lithium-ion a suscité une certaine inquiétude concernant l'approvisionnement en matières premières critiques nécessaires à leur production, en particulier les ressources en Li, Co, Ni et Cu. La technologie Sodium-ion apparait comme une alternative pouvant utiliser des ressources abondantes et uniformément réparties, et qui pourrait réduire le coût des batteries par rapport au Lithium-ion. Toutefois, le débouché commercial des batteries Sodium-ion est encore limité par le développement de matériaux d'électrode négative à haute performance et bas coût. L'option

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29

Stimson, Andrew Graham. "Fluvial carbon dynamics in degraded peatland catchments." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/fluvial-carbon-dynamics-in-degraded-peatland-catchments(94f066bd-cf18-4de3-9e4f-339476994fbf).html.

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Inland waters including streams, rivers, reservoirs and lakes are regarded as a significant site of Organic Carbon (OC) cycling, and greenhouse gas production. As a result, there has been significant recent interest in the rates and fate of fluvial carbon exported from organic soils, such as peatlands. Additionally, peatlands can be subject to substantial degradation resulting in high rates of fluvial OC export, and this has led to efforts to repair degraded peatlands through restoration programmes. As a consequence, the study of degraded areas is useful to quantify the upper values of carbon

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30

Schultz, Rachel Eileen. "Plant Diversity and Community Composition Effects on Carbon Cycling and Nitrogen Partitioning in Freshwater Wetlands." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275400132.

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31

Poudyel, Ghimire Pramila. "DEVELOPMENT OF PHENOLIC RESIN-DERIVED CARBONS AND THEIR COMPOSITES WITH TAILORED COMPOSITION, POROSITY AND MORPHOLOGY." Kent State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=kent157384419976016.

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32

Bonne, Jean-Louis. "Observations continues de la composition atmosphérique au sud Groenland." Thesis, Versailles-St Quentin en Yvelines, 2015. http://www.theses.fr/2015VERS008V/document.

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Le but de ma thèse est de conduire et d’utiliser les premières observations atmosphériquesde surface du CO2, de l’O2, du CH4 et de la composition isotopique de la vapeur d’eau et desprécipitations dans la région peu instrumentée du sud du Groenland. Quelles informations cesobservations locales peuvent-elles nous apporter à la fois concernant les processus atmosphériqueslocaux et concernant le transport atmosphérique à grande échelle ? Peut-on en extrairedes informations sur les échanges entre la surface et l’atmosphère, qui constituent une part crucialedes cycles biogéochimiques du carbone et

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33

Stevens, Erin N. "Photosynthesis in the intertidal macroalga Fucus vesiculosus L. (Phaeophyta) an investigation into the composition of a stored carbon pool /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.49 Mb., 77 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1430763.

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34

Binoka, Danfung Teresa. "Effect of Phosphorus Fertiliser on Soil Organic Matter Composition of Hill Country Pasture." The University of Waikato, 2008. http://hdl.handle.net/10289/2225.

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Soil organic matter is important as storage for carbon and nutrients, supporting soil structure, and as a filter for pollutants entering the soil ecosystem. The recovery of soil organic matter in depleted soils can take decades, or even hundreds of years. It has been assumed that in non-eroding pasture, soil carbon levels either increase or not change over time. However, some recent studies have suggested that fertiliser addition to pasture soils may contribute to decreases in soil carbon content. My hypotheses were: 1. As P fertiliser loadings increase the soil carbon content and C:N ratio wi

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35

Murray, Andrew P. "Factors controlling the abundance and carbon isotopic composition of land-plant derived compounds in crude oils." Curtin University of Technology, Centre for Petroleum and Environmental Organic Geochemistry, 1998. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=10771.

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This thesis describes a study in petroleum geochemistry and specifically of the application of Land-plant derived hydrocarbons to elucidating source matter type, depositional environment and thermal maturity of crude oils. Large volumes of petroleum have been generated from land-plant organic matter in many parts of the world, but especially in the Tertiary deltaic provinces of the USA, Canada, Africa, Southeast Asia, Australia and New Zealand. Compared to oils from other regions, these oils have a relatively complex pattern of biomarkers or molecular fossils, a feature reflecting the diversit

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36

Van, Winkle Stephen C. "The effect of activated carbon on the organic and elemental composition of plant tissue culture medium." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/7092.

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37

Carvajal-Ortiz, Humberto. "Carbon isotopic composition of plant-derived organic matter in tropical sedimentary sequences as a recorder of Late Cretaceous-Early Paleogene changes in the carbon cycle." [Ames, Iowa : Iowa State University], 2007.

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38

Serre, Aurélie. "Développement du procédé de densification rapide appliqué au carbure de silicium." Thesis, Orléans, 2013. http://www.theses.fr/2013ORLE2004/document.

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Les procédés d’élaboration de Composites à Matrice Céramique (CMC) utilisés aujourd’hui à l’échelle industrielle sont longs et par conséquent coûteux. Dans ce contexte, le procédé de densification rapide ou procédé de caléfaction, jusque-là essentiellement connu pour l’élaboration de carbone, permettant de réduire considérablement les durées d’élaboration, apparaît intéressant. Cette étude est axée sur le développement du procédé de caléfaction dans le but d’élaborer des carbures, matériaux connus pour leurs bonnes propriétés à haute température, et plus particulièrement du carbure de silicium

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39

Upsdell, Brynn. "The carbon and nitrogen composition of suspended particulate matter in Lake Erie, selected tributaries, and its outflow." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1219.

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Since their introduction to Lake Erie, dreissenid mussels may have reengineered the cycling of nutrients in the lake so that the nearshore benthic community intercepts, retains, and recycles greater quantities of nutrients. This study traces particulate matter on a basin scale by characterizing the chemical composition (POC and PN concentrations, POC/PN mass ratios, δ<sup>13</sup>C and δ<sup>15</sup>N) of suspended particulate matter in Lake Erie, three tributary inflows, and the lake outflow between May and October, 2002. The data are used to 1) determine the relative contri

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40

Werner, Jörn. "The influence of composition, processing and temperature on the Young's modulus of elasticity of carbon-bonded refractories." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-155296.

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Thermal shock resistance is a key property of refractory materials. Its determination and prediction is essential for the design of structural refractories as well as lining materials. Young’s modulus of elasticity (E) is a crucial parameter for the calculation of thermal shock resistance. For all investigated carbon-bonded alumina composition a significant increase of E was observed. This increase was attributed to a mismatch of the coefficient of thermal expansion of the composite constituents. Besides others, the graphite content as well as the maximum alumina particle size were identified

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41

Knobloch, Amanda. "Fluxes, drivers, and composition of carbon exchanged at the Taskinas Creek, VA coastal marsh creek-estuarine interface." W&M ScholarWorks, 2019. https://scholarworks.wm.edu/etd/1582642587.

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Among the most valuable natural ecosystems, estuaries and marshes are areas of high productivity, have high economic value, and provide numerous ecosystem services. However, there is still uncertainty in marsh and estuarine carbon budgets and in our overall understanding of the drivers, composition, and fluxes of organic matter in these habitats. Part of this uncertainty is due to high spatial and temporal variability within these habitats and the range of methods used in previous studies. While the number of studies is increasing, there are still large gaps in our knowledge of marsh-estuarine

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42

Nelson, Amelia Rose. "Heterogeneity in Hyporheic Flow, Pore Water Chemistry, and Microbial Community Composition in an Alpine Streambed." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555581246083891.

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43

Müller, Carsten. "Carbon sequestration and soil organic matter composition affected by altered soil aggregate dynamics due to land-use changes." kostenfrei, 2009. http://mediatum2.ub.tum.de/node?id=808703.

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44

Coleman, Joanna Michelle. "Controls on the distribution and carbon isotopic composition of archaeal biomarkers in organic-rich and methanogenic marine sediments." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416770.

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45

Roman, Dobarco Mercedes. "Influence of Stand Composition on Soil Organic Carbon Stabilization and Biochemistry in Aspen and Conifer Forests of Utah." DigitalCommons@USU, 2014. https://digitalcommons.usu.edu/etd/3300.

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Quacking aspen (Populus tremuloides Michx.) is an iconic species in western United States that offers multiple ecosystem services, including carbon sequestration. A shift in forest cover towards coniferous species due to natural succession, land management practices, or climate change may modify soil organic carbon (SOC) dynamics and CO2 emissions. The objectives of this study were to: (i) assess the effects of overstory composition on SOC storage and stability across the aspen-conifer ecotone, (ii) use Fourier transform infrared spectroscopy attenuated total reflectance (FTIR-ATR) to assess w

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46

Motaragheb, Jafarpour Saeed. "Investigation of catalyst composition for cobalt and iron catalyst on the chirality of grown single walled carbon nanotubes." Thesis, Umeå universitet, Institutionen för fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-133186.

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The synthesis of type-enriched semiconducting or metallic single-walled carbon nanotubes (sc/m-SWCNTs) with high quality by means of catalytic chemical vapor deposition (CCVD) are essential prerequisites for implementing of SWCNTs into nanodevices. In particular, the Fe−Co bimetallic catalysts system is promising due to its ability to grow SWCNTs by CCVD. However, there is still a gap in understanding how to adjust catalyst composition aiming further improvements in SWCNTs properties with respect to the electronic type. In particular, formation of well-defined nanoalloy of bimetallic catalysts

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47

Launois, Thomas. "Modélisation de la composition isotopique des cernes d'arbres (13C et 18O) et des transferts de COS entre l'atmosphère et la biosphère continentale pour quantifier les flux bruts de carbone." Thesis, Versailles-St Quentin en Yvelines, 2014. http://www.theses.fr/2014VERS0039/document.

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Dans un contexte de changement climatique, le fonctionnement de la biosphère continentale peut être durablement affecté par l’augmentation d’extrêmes climatiques, diminuant l’assimilation photosynthétique du carbone ou augmentant la respiration de l’écosystème. Quantifier le stockage de carbone par les écosystèmes et prédire leur sensibilité aux changements climatiques repose donc fortement sur notre capacité à diagnostiquer séparément les flux de photosynthèse et de respiration à différentes échelles. La productivité primaire brute (GPP) n’est cependant pas directement mesurable. Des approche

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48

Maddi, Chiranjeevi. "Laser technologies for the development of carbon materials for environmental analytical microsystems." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES014/document.

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Technologies laser pour l’élaboration de matériaux carbonés pour microsystèmes analytiques environnementaux. Pas de résumé en français fourni<br>Amorphous carbon nitride (a-CzN) material has attractor much attention in research and development. Recently, it has become a more promising electrode material than conventional carbon based electrodes in electrochemical and biosensor applications. Nitrogen containing amorphous carbon (a-C:N) thin films have been synthesized by femtosecond pulsed laser deposition (fs-PLD) coupled with plasma assistance through Direct Current (DC) bias power supply. Du

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Alvarado-Ochoa, Soraya Patricia. "CHARACTERIZATION OF SOIL CARBON STABILIZATION IN LONG-TERM ROW-CROPPED AGRO-ECOSYSTEMS." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/93.

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Soil organic matter (SOM) is a dynamic soil property, sensitive and responsive to many factors. The possibility of increasing soil carbon (C) sequestration by changing land use and management practices has been of great interest recently due to concerns with global changes in the atmospheric carbon dioxide (CO2) balance. Nonetheless, as a result of the complex dynamics of SOM, there is still the need for SOM characterization procedures capable of monitoring SOM stabilization, taking into account all the factors involved. This study characterized SOM stabilization as affected by management prac

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Najfach, Aaron Jacob. "EFFECT OF MANGANESE AND ZEOLITE COMPOSITION ON ZEOLITE-SUPPORTED NICKEL CATALYSTS FOR DRY REFORMING OF METHANE." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1501673873019245.

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