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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Measuring the Social Impacts of Carbon Offsetting: Forest-Based Carbon Capture and Improved Biomass Cook Stoves in Central America / Forest-Based Carbon Capture and Improved Biomass Cook Stoves in Central America

Shenkin, Evan Nathaniel 12 1900 (has links)
viii, 120 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / International carbon offset projects are framed as a cost effective, market based approach to address global warming through the cap-and-trade model of greenhouse gas emissions trading. Emission reduction projects in the Global South attempt to mitigate or "offset" pollution in the Global North by taking advantage of economic poverty in the developing world. This thesis investigates two development projects in Central America to explore the social impacts of carbon offsetting on communities. The research findings suggest that corporate support for emissions trading disproportionately benefits business interests while remaining largely unaccountable for project outcomes. This thesis argues that cap-and-trade in general and the US voluntary emissions trading market in particular are fundamentally flawed systems incapable of effectively addressing climate change and suggests sustainable alternatives to carbon offsetting. / Committee in Charge: Dr. Galen Martin, Chair; Dr. Derrick L. Hindery; Dr. Kathie Carpenter
82

A comparative study of energy-related carbon dioxide emissions from South Africa and selected countries

Pera, Nicoletta 05 February 2009 (has links)
M.Sc. / Increases in carbon dioxide (CO2) and other atmospheric trace gases, such as methane (CH4), can attribute to what has been called greenhouse warming because these compounds allow the sun’s energy to reach the surface of the earth, thereby warming it, while preventing much of that energy from being radiated to outer space. Over the past few decades, human activity has increasingly overloaded the Earth’s natural greenhouse system. Energy-related activities are the most significant contributor to greenhouse gas emissions. Emissions from fossil fuel combustion comprise the vast majority of these energy-related emissions. Carbon dioxide is the most significant greenhouse gas for South Africa. Due to the high content of coal in the energy mix, South Africa’s carbon emissions are proportionately greater in comparison with many other countries. The objective of this study is to study and analyse South Africa’s carbon emissions. This research will investigate: • South Africa’s historical trend in carbon emissions • Emissions by source and sector • The study will then deal with comparing South Africa’s energy-related carbon emissions to Argentina and Brazil which are similar middle-income developing countries and Australia and Spain which are developed countries • From here the study will focus on why South Africa’s carbon emissions differ, or are similar to, these other countries and • How South Africa’s carbon emissions impact on the total global carbon emissions. Included is a section discussing background information on the South African energy sector. Data for the South African study was calculated from the energy balances for the country for the study period. For the calculation of the carbon emissions for South Africa the IPCC top-down methodology was used. It can be seen that South Africa’s carbon emissions are still increasing. It was noted however that the values of the carbon emissions differ depending on which emission factors are used. For the International perspective information was obtained from the Internet and plotted on graphs. Information was obtained for the following countries: Argentina, Australia, Brazil, South Africa and Spain. From this study it was seen that South Africa’s carbon dioxide emissions are the highest out of all the countries in this study, while Argentina’s are the lowest. While most countries have energy conservation regulations, energy efficiency standards in South Africa are lacking. The process towards accession to the Kyoto Protocol in South Africa started in February 2000. The South African government has signed the United Nations Framework Convention on Climate Change (UNFCCC) in 1993. It has not yet ratified the Kyoto Protocol, but is currently in the process. This will however still take time and it is for this reason that the clean development mechanism holds the most promise for South Africa to participate in international greenhouse gas emission reduction projects.
83

The effect of vinblastine on the incorporation of C14-formate into the acid-soluble fraction of thymus cell suspensions.

Jones, Richard Gareth Wyn January 1963 (has links)
In earlier studies by Beer¹ the alkadloid vinblastine, VLB, has been shown to cause an almost complete inhibition in the incorporation of C¹⁴-formate into the deoxyribonucleic acid (DNA) of rat bone marrow in vivo. Also the incorporation of the same isotope into the DNA of suspensions of rat bone marrow and thymus cells in vitro was substantially depressed within one hour by the presence of the alkaloid² . In this work, the effect of VLB on the incorporation of C¹⁴-formate into the purine and pynmidine bases isolated from the hydrolysed acid-soluble fraction of thymus cell preparations was studied. A method for the separation of the constituents of this fraction was standardized and some of the major ultraviolet absorbing and radio-active compounds were identified. In general, VLB did not cause a marked depression in the incorporation of C¹⁴ -formate into the bases isolated from the hydrolysed acid-soluble fraction of either washed or unwashed cell suspensions. It was therefore considered probable that vinblastine did not inhibit the activation of 1-carbon units by tetrahydrofolic acid or their transfer. Also the results indicated that the de novo synthesis of the purine and pyrimidine compounds was not inhibited by the alkaloid. It is tentatively suggested that VLB inhibits a step in the incorporation of the mononucleotides into the nucleic acids. Comparison of the compounds isolated from the hydrolysed acid-soluble fractions of washed and unwashed cell preparations showed that considerably less hypoxanthine and xanthine were recovered from the former. VLB was found to markedly increase the total radio-activity of serine in washed cell preparations in the third hour of incubation but this effect was not pronounced in unwashed cell preparations. The total count of adenine decreased in the third hour of washed cell incubations in the presence of VLB. Neither the effect on serine nor on adenine is considered to be directly related to the inhibition of DNA synthesis as the latter is apparent within only 1 hour's incubation. Washing appears to increase the sensitivity of certain biochemical changes in the cell. It is tentatively suggested that the appearances of changes in the total radio-activity of adenine may be related to the loss of a substrate on washing. 1 Beer, C.T., Canadian Cancer Conference 4, 355 (1961) Academic Press, Inc., New York. 2 Richards, J.F., and Beer, C.T., personal communication. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate
84

The oxidation of carbon by lead oxide-silica melts

Jena, Prafulla Kumar January 1959 (has links)
An investigation of the oxidation of carbon by lead oxide-silica melts was undertaken. The carbon specimens utilised in this investigation were spectroscopic graphite,, petroleum coke (baked at 900°C) and spectroscopic carbon. The kinetics of the reactions were studied for different geometric surface areas over a wide range of concentrations of lead oxide and at different temperatures. In all cases the rate of oxidation was found to be directly proportional to the geometric surface area of the carbon sample used. The rate was also proportional to the square of the activity of lead oxide or equilibrium pressure of O₂ obtained from the dissociation of PbO in the melt. The experimental rate constant k values were calculated. The values of k for the oxidation of graphite, petroleum coke and carbon at 1000°C were found to be 1.35 x 10⁻², 1.31 x 10⁻² and 0.97 x 10⁻² gm.C/cm²/min. respectively. The values of the experimental activation energies of the oxidation of graphite, petroleum coke and carbon were found to be 33* 28 and 22 kilo-calories per mole respectively. In all cases carbon dioxide was the product gas. The results obtained in the present investigation indicated that the stoichiometry of the reaction is two molecules of lead oxide and an atom of carbon to produce metallic lead and carbon dioxide. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate
85

The Raman effect in liquid and gaseous carbon disulfide

Nikkel, Ruben Frank January 1951 (has links)
High intensity mercury arc light sources were constructed for the investigation of Raman spectra. Raman tubes for liquids and gases were made and used for the study of the Raman Effect in liquid and gaseous carbon disulfide. The spectrum of liquid CS₂ was obtained using exposure times ranging from three minutes to two hours. The two principal Raman bands and one companion line for each band were observed and measured to an accuracy of within±0.5 cmˉ¹. The values found for the frequency shifts agree, within experimental error, with those of Langseth, Sorensen and Neilsen( 24). The spectrum of gaseous CS₂ was obtained with the gas at three atmospheres pressure and exposure times of twelve to thirty hours. Three previously unreported lines were observed in addition to the band reported by Imanishi(20) at 655 cmˉ¹. Their frequencies are compared below with those observed in the spectrum of liquid CS₂. (Formula omitted) / Science, Faculty of / Physics and Astronomy, Department of / Graduate
86

The surface reaction of chlorine and activated carbon at low pressures

Boyd, Alan William January 1947 (has links)
The nature of the surface reaction of chlorine with activated carbon was investigated in the following way. A measured amount of chlorine was admitted to outgassed charcoal and pressure and temperature readings taken over the pressure range 10⁻⁵ - 10⁻² mm. Chlorine was removed in increments until a series of isosteres were obtained in the temperature range -183° to 1180°C. From these functions desorption isobars and heats of adsorption were calculated. Conclusions were drawn from the values of these as to the nature of the surface reaction of the chlorine and activated carbon. / Science, Faculty of / Chemistry, Department of / Graduate
87

Rearrangements in carbenoid decomposition of 2,2,2-triaryldiazoethanes /

Sargeant, Peter Barry January 1962 (has links)
No description available.
88

Karola Toth

Karola, Toth 12 1900 (has links)
ABSTRACT The effects of restoration on dissolved organic carbon (DOC) dynamics were examined at the Boi~-des-Bel peatland. This study included both laboratory measurements of DOC production by different peatland vegetative components and field measurements of DOC dynamics within a recently restored, a cutover and a natural peatland. Shrub and herbaceous plant material were found to be the most significant producers of DOC in the short term. Moss, peat and straw samples had a high potential to release DOC ;;ontinuously under warm, moist and aerobic conditions. On a short timescale, all components have the potential to release the three dissolved organic matter (DOM) fractions examined with humic acid (HA) most prominently being produced by shrubs and herbaceous plants and hydrophilic (HPI) and hydrophobic (HPO) fractions by mosses, peat and straw. Comparison of growing season results over three study years at the restored and cutover site indicated that DOC concentrations increased after restoration while DOC export decreased due to lowered runoff caused by the blockage of drainage ditches. Compared to the natural peatland, both the restored and the cutover site had a more humic DOM character. No difference could be found between the character of DOM released from the restored and cutover sites. The most active layer of DOM production was the top 75 em where the water iii table fluctuated during the season. Water storage units such as pools and ditches also play an important role in DOM export from the site. Spring snowmelt was found to be the most significant DOC export event of the study season in 2001, when export values were significantly larger than those measured during the growing season. Solubility of the different DOM fractions was the main controlling factor on the DOM character seen at the outflows. Storm events contributed significantly to the summer DOC output. DOC dynamics were affected by antecedent moisture conditions and differences emerged between the restored and cutover site during this period. The results of this study emphasize the importance of managing water table fluctuations and the restoration (reestablishment) of Sphagnum species in order to improve the retention of DOM within cutover peatlands. / Thesis / Master of Science (MS)
89

Sulfone mediated synthesis of heterocycles on solid support

Arvanitis, Elena-Alexia January 2000 (has links)
No description available.
90

Enantiospecific syntheses of alkaloids from carbohydrates

Lunn, R. J. January 1986 (has links)
No description available.

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