18,092 research outputs found

    Incorporation of Nitrogen into Organics Produced by Fischer-Tropsch Type Chemistry

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    Laboratory simulations have demonstrated that hydrothermal systems have the potential to produce a range of organic compounds through Fischer-Tropsch type (FTT) chemistry. The distribution of products depends on several factors, including the abundance and composition of feed-stock molecules, reaction temperature, and the physical and chemical characteristics of catalytic materials included in the reactions. The majority of studies per-formed to date have focused solely on inclusion of CO2 or CO and H2 as the carbon, oxygen and hydrogen sources, which limits the possible products to hydro-carbons, alcohols and carboxylic acids. A few studies have included nitrogen in the form of ammonia, which led to the production of amino acids and nitrogenous bases; and a separate suite of studies included sulfur as sulfide minerals or H2S, which yielded products such as thiols and amino acids. Although these demonstrations provide compelling evidence that FTT reactions can produce compounds of interest for the origins of life, such reactions have been conducted under a very limited range of conditions and the synthetic reaction mechanisms have generally not been well-characterized. As a consequence, it is difficult to extrapolate these results to geologic systems or to evaluate how variations in reactant compositions would affect the distribution of products over time. We have begun a series of laboratory experiments that will incorporate a range of precursor molecules in varying compositions to determine how these variables affect the relative amounts and speciation of life-essential elements in organic molecules produced under FTT conditions. In the present work, we focus on systems containing C, H, O and N

    Population assessment of the vermilion snapper, Rhomboplites aurorubens, from the Southeastern United States

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    Changes in the age structure and population size of vermilion snapper, Rhornboplites aurorubens, from North Carolina through the Florida Keys were examined using records of landings and size frequencies of fish from commercial, recreational, and headboat fisheries from 1986-1996. Population size in numbers at age was estimated for each year by applying separable virtual population analysis (SVPA) to the landings in numbers at age. SVPA was used to estimate annual, age-specific fishing mortality (F) for four levels of natural mortality (M = 0.20, 0.25, 0.30, and 0.35). Although landings of vermilion snapper for the three fisheries have declined, minimum fish size regulations have resulted in an increase in the mean size of fish landed. Age at entry and age at full recruitment were age-1 andage-3 fDr 1986-1991, compared with age-1 and age-4, respectively, for 1992-1996. Levels of mortality from fishing (F) ranged from 0.38 - 0.61 for the entire period. Current spawning potential ratio (SPR) is 21% or 27% depending on the natural mortality estimate. SPR could be raised to 30% or 40% with a reduction in F, or by increasing the age at entry to the fisheries. The latter could be enhanced now if fishermen, particularly recreational, comply with minimum size regulations. However, released fish mortality, modeled in the assessment at 27%, will continue to make the achievement of 30% and 40% SPR more difficult. (PDF contains 63 pages

    An Evaluation of Tennessee Soybean Growers’ Views on a New Generation Cooperative to Produce Biodiesel

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    Substituting petroleum diesel with biodiesel could decrease air emissions, reduce reliance on foreign oil, and help expand markets for U.S. farmers. Soybean producers can potentially capture this value-added by forward integrating the processing of soybeans into biodiesel via a New Generation Cooperative (NGC). Using probit analysis, this study examines factors influencing soybean producers’ willingness to participate in an NGC to produce biodiesel. Tobit analysis is used to examine the factors influencing the number of shares the soybean producer would be willing to purchase. Survey results indicate that over 70% of the soybean producers in the study group are interested in investing in an NGC to produce biodiesel. Among those producers willing to participate, the average number of shares they would purchase was just under 3,460.biodiesel, New Generation Cooperative, probit analysis, soybean producers, tobit analysis, Marketing, Research Methods/ Statistical Methods,

    Willingness to Pay for Emission Reductions with E85

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    This study examines consumers' WTP for reductions in greenhouse gas emissions from E85 as opposed to gasoline. Data were collected via a contingent choice exercise in a 2009 national online survey. As part of the fuel choice exercise, several fuel attributes were allowed to vary including emission reductions, import level, proximity of fuel availability, price, and fuel blend (E85 or regular gasoline). A random parameters model with demographics and attitudes interacted with emission reductions was estimated. The resulting estimates suggest that, overall the WTP for an emission reduction is not statistically significant. However, for some demographic and attitudinal profiles, the WTP is significant. An example profile includes younger age, female, concerned about climate change, not supportive of additional drilling, supportive of farmland being used for fuel, own or are likely to own a FlexFuel vehicle, and primary vehicle not an SUV.Willingness to Pay, Emission Reductions, E85, Consumer/Household Economics, Environmental Economics and Policy, Q41, Q51,

    Sixty Billion Gallons by 2030: Economic and Agricultural Impacts of Ethanol and Biodiesel Expansion

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    Agriculture is well positioned as a feedstock source because the fuels can be utilized with current engine technologies and are compatible with the current distribution infrastructure. Commercialization of cellulosic to ethanol technology will enable fuels to be derived from a diverse portfolio of feedstocks from numerous regions of the country. The levels of ethanol production analyzed are 10, 30, and 60 billion gallons of ethanol annually by 2010, 2020 and 2030, respectively. Impacts of producing 1 billion gallons of biodiesel production by 2012 and 1.6 billion gallons by 2030 are also projected. Overall, for the period 2007 to 2030, the estimated accumulated gains in net farm income are over 210billion;andtheaccumulatedpotentialsavingsingovernmentpaymentsareestimatedtobe210 billion; and the accumulated potential savings in government payments are estimated to be 150 billion. Due to the geographic decentralization of the production of feedstock, economic gains are projected to accrue to the majority of regions of the country. Significant expansion beyond 60 billion gallons per year would likely require expansion of the region suitable for the production of bioenergy crops, ability to convert other pastureland (beyond cropland in pasture) into energy crops; allowing CRP acreage to be used in feedstock production, increasing short-rotation wood crops in the Northeast and Northwest regions, increased yields above those assumed in the analysis, and/or increasing the efficiency of cellulosic conversion. Further research should examine the agricultural, environmental, and economic impacts of one or more these factors changing.Resource /Energy Economics and Policy,

    Cost Analysis of Alternative Harvest, Storage and Transportation Methods for Delivering Switchgrass to a Biorefinery from the Farmers’ perspective

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    Switchgrass for bioenergy production will require substantial storage. This study evaluated costs of alternative baling and on-farm storage systems. Rectangular bales minimize cost if switchgrass is processed immediately after harvest. However, round bales minimize cost if switchgrass is stored under cover for 200 days before transporting to the biorefineryswitchgrass, baling, storage, transport, costs, farm, biorefinery, Agricultural Finance, Farm Management, Production Economics, Resource /Energy Economics and Policy,

    CONSUMER PREFERENCES FOR ELECTRICITY FROM BIOENERGY AND OTHER RENEWABLES

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    This study ascertains residential electricity consumers' support and willingness to pay for electricity from renewable sources. Then, willingness to pay for specified renewable energy sources (solar, wind, landfill wastes, bioenergy from fast growing crops, and bioenergy from forest products wastes). Effects of demographics and environmental behaviors are estimated.Institutional and Behavioral Economics,
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