1,292,759 research outputs found

    Combustion method for assay of biological materials labeled with carbon-14 or tritium, or double-labeled

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    Dry catalytic combustion at high temperatures is used for assaying biological materials labeled carbon-14 and tritium, or double-labeled. A modified oxygen-flask technique is combined with standard vacuum-line techniques and includes convenience of direct in-vial collection of final combustion products, giving quantitative recovery of tritium and carbon-14

    The Incidence of a U.S. Carbon Tax: A Lifetime and Regional Analysis

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    This paper measures the direct and indirect incidence of a carbon tax using current income and two measures of lifetime income to rank households. Our results suggest that carbon taxes are more regressive when annual income is used as a measure of economic welfare than when proxies for lifetime income are used. Further, the direct component of the tax, in any given year, is significantly more regressive than the indirect component. In fact, for 1987, the indirect component of the tax is mildly progressive. We observe a modest shift over time with the direct component of carbon taxes becoming less regressive and the indirect component becoming more regressive. These effects mostly offset each other and the distribution of the total tax burden has not changed much over time. In addition we find that regional variation has fluctuated over the years of our anlaysis. By 2003 there is little systematic variation in carbon tax burdens across regions of the country.

    Quantitative conversion of water to carbon dioxide

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    Method quantitatively converts water vapor to carbon dioxide permitting direct and rapid analysis of mixed-gas streams for water content

    The Incidence of a U.S. Carbon Tax: A Lifetime and Regional Analysis

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    This paper measures the direct and indirect incidence of a carbon tax using current income and two measures of lifetime income to rank households. OUr results suggest that carbon taxes are more regressive when annual income is used as a measure of economic welfare that when proxies for lifetime income are used. Further, the direct component of the tax, in any given year, is significantly more regressive than the indirect component. In fact, for 1987, the indirect component of the tax is mildly progressive. We observe a modest shift over time with the direct component of carbon taxes becoming less regressive and the indirect component becoming more regressive. These effects mostly offset each other and the distribution of the total tax burden has not changed much over time. In addition we find that regional variation has fluctuated over the years of our analysis. By 2003 there is little systematic variation in carbon tax burdens across regions of the country.

    Direct Observation of Molecular Oxygen Production from Carbon Dioxide

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    Oxygen (O2O_2) is one of the most important elements required to sustain life. The concentration of O2O_2 on Earth has been accumulated over millions of years and has a direct connection with that of CO2CO_2. Further, CO2CO_2 plays an important role in many other planetary atmospheres. Therefore, molecular reactions involving CO2CO_2 are critical for studying the atmospheres of such planets. Existing studies on the dissociation of CO2CO_2 are exclusively focused on the C--O bond breakage. Here we report first experiments on the direct observation of molecular Oxygen formation from CO2CO_2 in strong laser fields with a reaction microscope. Our accompanying simulations suggest that CO2CO_2 molecules may undergo bending motion during and after strong-field ionization which supports the molecular Oxygen formation process. The observation of the molecular Oxygen formation from CO2CO_2 may trigger further experimental and theoretical studies on such processes with laser pulses, and provide hints in studies of the O2O_2 and CO2+CO_2^+ abundance in CO2CO_2-dominated planetary atmospheres

    Carbon phenolic heat shields for Jupiter/Saturn/Uranus entry probes

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    Carbon phenolic heat shield technology is reviewed. Heat shield results from the outer planetary probe mission studies are summarized along with results of plasma jet testing of carbon phenolic conducted in a ten megawatt facility. Missile flight data is applied to planetary entry conditions. A carbon phenolic heat shield material is utilized and tailored to accommodate each of the probe missions. An integral heat shield approach is selected over in order to eliminate a high temperature interface problem and permit direct bonding of the carbon phenolic to the structural honeycomb sandwich. The sandwich is filled with a very fine powder to minimize degradation of its insulation properties by the high conductive hydrogen/helium gases during the long atmospheric descent phase

    Degradation and forgone removals increase the carbon impact of intact forest loss by 626%

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    Intact tropical forests, free from substantial anthropogenic influence, store and sequester large amounts of atmospheric carbon but are currently neglected in international climate policy. We show that between 2000 and 2013, direct clearance of intact tropical forest areas accounted for 3.2% of gross carbon emissions from all deforestation across the pantropics. However, full carbon accounting requires the consideration of forgone carbon sequestration, selective logging, edge effects, and defaunation. When these factors were considered, the net carbon impact resulting from intact tropical forest loss between 2000 and 2013 increased by a factor of 6 (626%), from 0.34 (0.37 to 0.21) to 2.12 (2.85 to 1.00) petagrams of carbon (equivalent to approximately 2 years of global land use change emissions). The climate mitigation value of conserving the 549 million ha of tropical forest that remains intact is therefore significant but will soon dwindle if their rate of loss continues to accelerate
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