WorldWideScience

Sample records for net gas production

  1. Re-assessment of net energy production and greenhouse gas emissions avoidance after 40 years of photovoltaics development

    Science.gov (United States)

    Louwen, Atse; van Sark, Wilfried G. J. H. M.; Faaij, André P. C.; Schropp, Ruud E. I.

    2016-12-01

    Since the 1970s, installed solar photovoltaic capacity has grown tremendously to 230 gigawatt worldwide in 2015, with a growth rate between 1975 and 2015 of 45%. This rapid growth has led to concerns regarding the energy consumption and greenhouse gas emissions of photovoltaics production. We present a review of 40 years of photovoltaics development, analysing the development of energy demand and greenhouse gas emissions associated with photovoltaics production. Here we show strong downward trends of environmental impact of photovoltaics production, following the experience curve law. For every doubling of installed photovoltaic capacity, energy use decreases by 13 and 12% and greenhouse gas footprints by 17 and 24%, for poly- and monocrystalline based photovoltaic systems, respectively. As a result, we show a break-even between the cumulative disadvantages and benefits of photovoltaics, for both energy use and greenhouse gas emissions, occurs between 1997 and 2018, depending on photovoltaic performance and model uncertainties.

  2. The effect of changing cow production and fitness traits on net income and greenhouse gas emissions from Australian dairy systems.

    Science.gov (United States)

    Bell, M J; Eckard, R J; Haile-Mariam, M; Pryce, J E

    2013-01-01

    The aim of this study was to compare the effect of changing a range of biological traits on farm net income and greenhouse gas emissions (expressed in carbon dioxide equivalents, CO2-eq.) in the Australian dairy cow population. An average cow was modeled, using breed-average information for Holsteins and Jerseys from the Australian Dairy Herd Improvement Scheme. A Markov chain approach was used to describe the steady-state herd structure, as well as estimate the CO2-eq. emissions per cow and per kilogram of milk solids. The effects of a single unit change in herd milk volume, fat and protein yields, live weight, survival, dry matter intake, somatic cell count, and calving interval were assessed. With the traits studied, the only single-unit change that would bring about a desirable increase in both net income and reduced emissions intensity per cow and per kilogram of milk solids in Australian dairy herds would be an increase in survival and reductions in milk volume, live weight, DMI, SCC, and calving interval. The models developed can be used to assess lifetime dairy system abatement options by breeding, feeding, and management. Selective breeding and appropriate management can both improve health, fertility, and feed utilization of Australian dairy systems and reduce its environmental impact. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  3. Re-assessment of net energy production and greenhouse gas emissions avoidance after 40 years of photovoltaics development

    NARCIS (Netherlands)

    Louwen, Atse|info:eu-repo/dai/nl/375268456; Van Sark, Wilfried G J H M|info:eu-repo/dai/nl/074628526; Faaij, André P C; Schropp, Ruud E I|info:eu-repo/dai/nl/072502584

    2016-01-01

    Since the 1970s, installed solar photovoltaic capacity has grown tremendously to 230 gigawatt worldwide in 2015, with a growth rate between 1975 and 2015 of 45%. This rapid growth has led to concerns regarding the energy consumption and greenhouse gas emissions of photovoltaics production. We

  4. Net sea–air CO2 flux uncertainties in the Bay of Biscay based on the choice of wind speed products and gas transfer parameterizations

    Directory of Open Access Journals (Sweden)

    P. Otero

    2013-05-01

    Full Text Available The estimation of sea–air CO2 fluxes is largely dependent on wind speed through the gas transfer velocity parameterization. In this paper, we quantify uncertainties in the estimation of the CO2 uptake in the Bay of Biscay resulting from the use of different sources of wind speed such as three different global reanalysis meteorological models (NCEP/NCAR 1, NCEP/DOE 2 and ERA-Interim, one high-resolution regional forecast model (HIRLAM-AEMet, winds derived under the Cross-Calibrated Multi-Platform (CCMP project, and QuikSCAT winds in combination with some of the most widely used gas transfer velocity parameterizations. Results show that net CO2 flux estimations during an entire seasonal cycle (September 2002–September 2003 may vary by a factor of ~ 3 depending on the selected wind speed product and the gas exchange parameterization, with the highest impact due to the last one. The comparison of satellite- and model-derived winds with observations at buoys advises against the systematic overestimation of NCEP-2 and the underestimation of NCEP-1. In the coastal region, the presence of land and the time resolution are the main constraints of QuikSCAT, which turns CCMP and ERA-Interim in the preferred options.

  5. HANPP Collection: Human Appropriation of Net Primary Productivity as a Percentage of Net Primary Productivity

    Data.gov (United States)

    National Aeronautics and Space Administration — The Human Appropriation of Net Primary Productivity (HANPP) as a Percentage of Net Primary Productivity (NPP) portion of the Human Appropriation of Net Primary...

  6. HANPP Collection: Human Appropriation of Net Primary Productivity as a Percentage of Net Primary Productivity

    Data.gov (United States)

    National Aeronautics and Space Administration — The Human Appropriation of Net Primary Productivity (HANPP) as a Percentage of Net Primary Product (NPP) portion of the HANPP Collection represents a map identifying...

  7. Net global warming potential and greenhouse gas intensity

    Science.gov (United States)

    Various methods exist to calculate global warming potential (GWP) and greenhouse gas intensity (GHG) as measures of net greenhouse gas (GHG) emissions from agroecosystems. Little is, however, known about net GWP and GHGI that account for all sources and sinks of GHG emissions. Sources of GHG include...

  8. EVo: Net Shape RTM Production Line

    OpenAIRE

    Sven Torstrick; Felix Kruse; Martin Wiedemann

    2016-01-01

    EVo research platform is operated by the Center for Lightweight-Production-Technology of the German Aerospace Center in Stade. Its objective is technology demonstration of a fully automated RTM (Resin Transfer Molding) production line for composite parts in large quantities. Process steps include cutting and ply handling, draping, stacking, hot-forming, preform-trimming to net shape, resin injection, curing and demolding.

  9. HANPP Collection: Global Patterns in Net Primary Productivity (NPP)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Patterns in Net Primary Productivity (NPP) portion of the Human Appropriation of Net Primary Productivity (HANPP) Collection maps the net amount of solar...

  10. EVo: Net Shape RTM Production Line

    Directory of Open Access Journals (Sweden)

    Sven Torstrick

    2016-04-01

    Full Text Available EVo research platform is operated by the Center for Lightweight-Production-Technology of the German Aerospace Center in Stade. Its objective is technology demonstration of a fully automated RTM (Resin Transfer Molding production line for composite parts in large quantities. Process steps include cutting and ply handling, draping, stacking, hot-forming, preform-trimming to net shape, resin injection, curing and demolding.

  11. HANPP Collection: Global Patterns in Net Primary Productivity (NPP)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Patterns in Net Primary Productivity (NPP) portion of the HANPP Collection maps the net amount of solar energy converted to plant organic matter through...

  12. Global Patterns in Human Consumption of Net Primary Production

    Science.gov (United States)

    Imhoff, Marc L.; Bounoua, Lahouari; Ricketts, Taylor; Loucks, Colby; Harriss, Robert; Lawrence William T.

    2004-01-01

    The human population and its consumption profoundly affect the Earth's ecosystems. A particularly compelling measure of humanity's cumulative impact is the fraction of the planet's net primary production that we appropriate for our Net primary production-the net amount of solar energy converted to plant organic matter through photosynthesis-can be measured in units of elemental carbon and represents the primary food energy source for the world's ecosystems. Human appropriation of net primary production, apart from leaving less for other species to use, alters the composition of the atmosphere, levels of biodiversity, flows within food webs and the provision of important primary production required by humans and compare it to the total amount generated on the landscape. We then derive a spatial ba!mce sheet of net primary production supply and demand for the world. We show that human appropriation of net primary production varies spatially from almost zero to many times the local primary production. These analyses reveal the uneven footprint of human consumption and related environmental impacts, indicate the degree to which human populations depend on net primary production "imports" and suggest policy options for slowing future growth of human appropriation of net primary production.

  13. Land Use Effects on Net Greenhouse Gas Fluxes in the US Great Plains: Historical Trends and Model Projections

    Science.gov (United States)

    Del Grosso, S. J.; Parton, W. J.; Ojima, D. S.; Mosier, A. R.; Mosier, A. R.; Paustian, K.; Peterson, G. A.

    2001-12-01

    We present maps showing regional patterns of land use change and soil C levels in the US Great Plains during the 20th century and time series of net greenhouse gas fluxes associated with different land uses. Net greenhouse gas fluxes were calculated by accounting for soil CO2 fluxes, the CO2 equivalents of N2O emissions and CH4 uptake, and the CO2 costs of N fertilizer production. Both historical and modern agriculture in this region have been net sources of greenhouse gases. The primary reason for this, prior to 1950, is that agriculture mined soil C and resulted in net CO2 emissions. When chemical N fertilizer became widely used in the 1950's agricultural soils began to sequester CO2-C but these soils were still net greenhouse gas sources if the effects of increased N2O emissions and decreased CH4 uptake are included. The sensitivity of net greenhouse gas fluxes to conventional and alternative land uses was explored using the DAYCENT ecosystem model. Model projections suggest that conversion to no-till, reduction of the fallow period, and use of nitrification inhibitors can significantly decrease net greenhouse gas emissions in dryland and irrigated systems, while maintaining or increasing crop yields.

  14. Limiting net greenhouse gas emissions in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, R A; Watts, E C; Williams, E R [eds.

    1991-09-01

    In 2988 the Congress requested DOE produce a study on carbon dioxide inventory and policy to provide an inventory of emissions sources and to analyze policies to achieve a 20% reduction in carbon dioxide emissions in 5 to 10 years and a 50% reduction in 15 to 20 years. This report presents the results of that study. Energy and environmental technology data were analyzed using computational analysis models. This information was then evaluated, drawing on current scientific understanding of global climate change, the possible consequences of anthropogenic climate change (change caused by human activity), and the relationship between energy production and use and the emission of radiactively important gases. Topics discussed include: energy and environmental technology to reduce greenhouse gas emissions, fossil energy production and electricity generation technologies, nuclear energy technology, renewable energy technologies, energy storage, transmission, and distribution technology, transportation, technology, industrial technology, residential and commercial building technology, greenhouse gas removal technology, approaches to restructuring the demand for energy.

  15. Fermentative biohydrogen production: Evaluation of net energy gain

    Energy Technology Data Exchange (ETDEWEB)

    Perera, Karnayakage Rasika J.; Ketheesan, Balachandran; Nirmalakhandan, Nagamany [Civil Engineering Department, New Mexico State University, Las Cruces, NM 88011 (United States); Gadhamshetty, Venkataramana [Civil and Environmental Engineering Dept., Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2010-11-15

    Most dark fermentation (DF) studies had resorted to above-ambient temperatures to maximize hydrogen yield, without due consideration of the net energy gain. In this study, literature data on fermentative hydrogen production from glucose, sucrose, and organic wastes were compiled to evaluate the benefit of higher fermentation temperatures in terms of net energy gain. This evaluation showed that the improvement in hydrogen yield at higher temperatures is not justified as the net energy gain not only declined with increase of temperature, but also was mostly negative when the fermentation temperature exceeded 25 C. To maximize the net energy gain of DF, the following two options for recovering additional energy from the end products and to determine the optimal fermentation temperature were evaluated: methane production via anaerobic digestion (AD); and direct electricity production via microbial fuel cells (MFC). Based on net energy gain, it is concluded that DF has to be operated at near-ambient temperatures for the net energy gain to be positive; and DF + MFC can result in higher net energy gain at any temperature than DF or DF + AD. (author)

  16. Winter respiratory C losses provide explanatory power for net ecosystem productivity

    NARCIS (Netherlands)

    Haeni, M.; Zweifel, R.; Eugster, W.; Gessler, A.; Zielis, S.; Bernhofer, C.; Carrara, A.; Grünwald, T.; Havránková, K.; Heinesch, B.; Marek, M.; Moors, E.; Schelhaas, M.J.; Buchmann, N.

    2017-01-01

    Accurate predictions of net ecosystem productivity (NEPc) of forest ecosystems are essential for climate change decisions and requirements in the context of national forest growth and greenhouse gas inventories. However, drivers and underlying mechanisms determining NEPc

  17. HANPP Collection: Human Appropriation of Net Primary Productivity (HANPP) by Country and Product

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Patterns in Human Appropriation of Net Primary Productivity (HANPP) portion of the HANPP Collection represents a digital map of human appropriation of net...

  18. Global climate change and terrestrial net primary production

    Science.gov (United States)

    Melillo, Jerry M.; Mcguire, A. D.; Kicklighter, David W.; Moore, Berrien, III; Vorosmarty, Charles J.; Schloss, Annette L.

    1993-01-01

    A process-based model was used to estimate global patterns of net primary production and soil nitrogen cycling for contemporary climate conditions and current atmospheric CO2 concentration. Over half of the global annual net primary production was estimated to occur in the tropics, with most of the production attributable to tropical evergreen forest. The effects of CO2 doubling and associated climate changes were also explored. The responses in tropical and dry temperate ecosystems were dominated by CO2, but those in northern and moist temperate ecosystems reflected the effects of temperature on nitrogen availability.

  19. Water use efficiency of net primary production in global terrestrial ...

    Indian Academy of Sciences (India)

    Water use efficiency; global terrestrial ecosystems; MODIS; net primary production; evapotranspiration;. Köppen–Geiger climate classification. ... Terrestrial plants fix or trap carbon dioxide via photosynthesis to produce the material ...... S W 2007 Evaluating water stress controls on primary production in biogeochemical and ...

  20. Net Farm Income Analysis of Maize Production in Gwagwalada Area ...

    African Journals Online (AJOL)

    This study examined net farm income of maize production in Gwagwalada Area Council of Federal Capital Territory. The specific objectives are to: identify the socio-economic characteristics of maize farmers in the study area, evaluate the costs and returns of maize production in the study area, and evaluate factors affecting ...

  1. Gas reserves, discoveries and production

    Energy Technology Data Exchange (ETDEWEB)

    Saniere, A

    2006-07-01

    Between 2000 and 2004, new discoveries, located mostly in the Asia/Pacific region, permitted a 71% produced reserve replacement rate. The Middle East and the offshore sector represent a growing proportion of world gas production Non-conventional gas resources are substantial but are not exploited to any significant extent, except in the United States, where they account for 30% of U.S. gas production. (author)

  2. Net greenhouse gas emissions at Eastmain-1 reservoir, Quebec, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Tremblay, Alain; Bastien, Julie; Bonneville, Marie-Claude; del Giorgio, Paul; Demarty, Maud; Garneau, Michelle; Helie, Jean-Francois; Pelletier, Luc; Prairie, Yves; Roulet, Nigel; Strachan, Ian; Teodoru, Cristian

    2010-09-15

    The growing concern regarding the long-term contribution of freshwater reservoirs to atmospheric greenhouse gases (GHG), led Hydro-Quebec, to study net GHG emissions from Eastmain 1 reservoir, which are the emissions related to the creation of a reservoir minus those that would have been emitted or absorbed by the natural systems over a 100-year period. This large study was realized in collaboration with University du Quebec a Montreal, McGill University and Environnement IIlimite Inc. This is a world premiere and the net GHG emissions of EM-1 will be presented in details.

  3. Isotopic tracers for net primary productivity for a terrestrial esocystem ...

    African Journals Online (AJOL)

    The coupling effect of vapour release and CO2 uptake during photosynthesis plays an important role in the carbon and hydrologic cycles. The water use efficiency (WUE) for transpiration was used in calculating the net primary productivity (NPP) for terrestrial ecosystem. Three parameters were used in calculating the water ...

  4. Limiting net greenhouse gas emissions in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, R A; Watts, E C; Williams, E R [eds.

    1991-09-01

    In 1988, Congress requested that DOE produce a study on carbon dioxide inventory and policy to provide an inventory of emissions sources and to analyze policies to achieve a 20% reduction in carbon dioxide emissions in 5 to 10 years and a 50% reduction in 15 to 20 years. Energy and environmental technology data were analyzed using computational analysis models. This information was then evaluated, drawing on current scientific understanding of global climate change, the possible consequences of anthropogenic climate change (change caused by human activity) and the relationship between energy production and use and the emission of radiatively important gases. Topics discussed include: state of the science in estimating atmosphere/climate change relationships, the potential consequences of atmosphere/climate change, us greenhouse emissions past and present, an approach to analyzing the technical potential and cost of reducing US energy-related greenhouse gas emissions, current policy base and National Energy Strategy actions, fiscal instruments, regulatory instruments, combined strategies and instruments, macroeconomic impacts, carbon taxation and international trade, a comparison to other studies.

  5. Photosynthetic behavior, growth and essential oil production of Melissa officinalis L. cultivated under colored shade nets

    Directory of Open Access Journals (Sweden)

    Graziele C Oliveira

    2016-03-01

    Full Text Available The modulation of light is of importance during cultivation of medicinal plants to obtain desirable morphological and physiological changes associated with the maximum production of active principles. This study aimed to evaluate the effect of the light spectrum transmitted by colored shade nets on growth, essential oil production and photosynthetic behavior in plants of lemon balm (Melissa officinalis L. Plants were cultivated in pots for 4-mo under black, red, and blue nets with 50% shading, and full sunlight exposure. Biometric and anatomical variables, essential oil yield, global solar radiation, photon flux density, chlorophyll content, and gas exchange parameters were measured in M. officinalis leaves. The results showed that despite being considered a partial shade plant, this species is able to adapt to full sunlight conditions without increasing biomass production. The spectral changes provided by colored shade nets did not caused any noticeable change in leaf anatomy of M. officinalis. However, the use of blue net resulted in increments of 116% in plant height, 168% in leaf area, 42% in chlorophyll content and 30% in yield of essential oil in lemon balm plants. These plant's qualities make the use of blue net a cultivation practice suitable for commercial use.

  6. Net Ecosystem Production and Actionable Negative Emissions Strategies

    Science.gov (United States)

    DeCicco, J. M.; Heo, J.

    2016-12-01

    Negative emissions strategies, designed to increase the rate at which carbon dioxide (CO2) and other greenhouse gases are removed from the atmosphere, are an important aspect of broader strategies for mitigating climate change. Not only is CO2 the dominant greenhouse gas and the one most intimately tied to existing commercial energy use, but it is also part of the global carbon cycle. On the order of 200 PgC•yr-1 circulates between the atmosphere and the major carbon stocks of the terrestrial biosphere, oceans and geosphere. Anthropogenic flows of roughly 10 PgC•yr-1 from fossil fuel use and 1 PgC•yr-1 from land-use change significantly exceed the Earth's natural carbon sink, and this imbalance causes the buildup of carbon in the atmosphere. In addition to strategies for reducing CO2 emissions, increasing negative emissions through carbon dioxide removal (CDR) is crucial for reducing carbon cycle imbalance in the near term as well as meeting long-term goals such as a 2°C limit. Terrestrial carbon management is important for both reducing emissions and enhancing sinks. Photosynthesis in terrestrial ecosystems is the form of CDR that is now most actionable, referring to mechanisms that can be economically implemented at meaningful scales without technology breakthroughs. Net ecosystem production (NEP) is a crucial metric for guiding CDR involving the terrestrial biosphere, including options such as bioenergy with carbon capture and storage (BECCS) and other forms of bio-based mitigation. We derive the necessary conditions for effective implementation of this category of negative emissions measures, emphasizing the importance of NEP measurement, baselines and appropriate methods of carbon accounting. We present a method for quantitative spatio-temporal analysis of land-use and land-cover changes for estimating landscape-scale NEP; provide a preliminary baseline NEP estimate for the continental United States; apply the method to reveal a cautionary tale

  7. HANPP Collection: Human Appropriation of Net Primary Productivity (HANPP) by Country and Product

    Data.gov (United States)

    National Aeronautics and Space Administration — The Human Appropriation of Net Primary Productivity (HANPP) by Country and Product portion of the HANPP Collection contains tabular data on carbon-equivalents of...

  8. Net community production in the bottom of first-year sea ice over the Arctic spring bloom

    Science.gov (United States)

    Campbell, K.; Mundy, C. J.; Gosselin, M.; Landy, J. C.; Delaforge, A.; Rysgaard, S.

    2017-09-01

    The balance of photosynthesis and respiration by organisms like algae and bacteria determines whether sea ice is net heterotrophic or autotrophic. In turn this clarifies the influence of microbes on atmosphere-ice-ocean gas fluxes and their contribution to the trophic system. In this study we define two phases of the spring bloom based on bottom ice net community production and algal growth. Phase I was characterized by limited algal accumulation and low productivity, which at times resulted in net heterotrophy. Greater productivity in Phase II drove rapid algal accumulation that consistently produced net autotrophic conditions. The different phases were associated with seasonal shifts in light availability and species dominance. Results from this study demonstrate the importance of community respiration on spring productivity, as respiration rates can maintain a heterotrophic state independent of algal growth. This challenges previous assumptions of a fully autotrophic sea ice community during the ice-covered spring.

  9. Variations of Terrestrial Net Primary Productivity in East Asia

    Directory of Open Access Journals (Sweden)

    Fangmin Zhang

    2012-01-01

    Full Text Available Due to the heterogeneity and complexity of terrestrial ecosystems of East Asia, a better understanding of relationships between climate change and net primary productivity (NPP distribution is important to predict future carbon dynamics. The objective of this study is to analyze the temporal-spatial patterns of NPP in East Asia (10°S - 55°N, 60 - 155°E from 1982 to 2006 using the process-based Boreal Ecosystem Productivity Simulator (BEPS model. Prior to the regional simulation, the annual simulated NPP was validated using field observed NPP demonstrating the ability of BEPS to simulate NPP in different ecosystems of East Asia.

  10. The EROI of Conventional Canadian Natural Gas Production

    Directory of Open Access Journals (Sweden)

    Jon Freise

    2011-11-01

    Full Text Available Canada was the world’s third largest natural gas producer in 2008, with 98% of its gas being produced by conventional, tight gas, and coal bed methane wells in Western Canada. Natural gas production in Western Canada peaked in 2001 and remained nearly flat until 2006 despite more than quadrupling the drilling rate. Canada seems to be one of many counter examples to the idea that oil and gas production can rise with sufficient investment. This study calculated the Energy Return on Energy Invested and Net Energy of conventional natural gas and oil production in Western Canada by a variety of methods to explore the energy dynamics of the peaking process. All these methods show a downward trend in EROI during the last decade. Natural gas EROI fell from 38:1 in 1993 to 15:1 at the peak of drilling in 2005. The drilling intensity for natural gas was so high that net energy delivered to society peaked in 2000–2002, while production did not peak until 2006. The industry consumed all the extra energy it delivered to maintain the high drilling effort. The inability of a region to increase net energy may be the best definition of peak production. This increase in energy consumption reduces the total energy provided to society and acts as a contracting pressure on the overall economy as the industry consumes greater quantities of labor, steel, concrete and fuel. It appears that energy production from conventional oil and gas in Western Canada has peaked and entered permanent decline.

  11. Net carbon flux in organic and conventional olive production systems

    Science.gov (United States)

    Saeid Mohamad, Ramez; Verrastro, Vincenzo; Bitar, Lina Al; Roma, Rocco; Moretti, Michele; Chami, Ziad Al

    2014-05-01

    Agricultural systems are considered as one of the most relevant sources of atmospheric carbon. However, agriculture has the potentiality to mitigate carbon dioxide mainly through soil carbon sequestration. Some agricultural practices, particularly fertilization and soil management, can play a dual role in the agricultural systems regarding the carbon cycle contributing to the emissions and to the sequestration process in the soil. Good soil and input managements affect positively Soil Organic Carbon (SOC) changes and consequently the carbon cycle. The present study aimed at comparing the carbon footprint of organic and conventional olive systems and to link it to the efficiency of both systems on carbon sequestration by calculating the net carbon flux. Data were collected at farm level through a specific and detailed questionnaire based on one hectare as a functional unit and a system boundary limited to olive production. Using LCA databases particularly ecoinvent one, IPCC GWP 100a impact assessment method was used to calculate carbon emissions from agricultural practices of both systems. Soil organic carbon has been measured, at 0-30 cm depth, based on soil analyses done at the IAMB laboratory and based on reference value of SOC, the annual change of SOC has been calculated. Substracting sequestrated carbon in the soil from the emitted on resulted in net carbon flux calculation. Results showed higher environmental impact of the organic system on Global Warming Potential (1.07 t CO2 eq. yr-1) comparing to 0.76 t CO2 eq. yr-1 in the conventional system due to the higher GHG emissions caused by manure fertilizers compared to the use of synthetic foliar fertilizers in the conventional system. However, manure was the main reason behind the higher SOC content and sequestration in the organic system. As a resultant, the organic system showed higher net carbon flux (-1.7 t C ha-1 yr-1 than -0.52 t C ha-1 yr-1 in the conventional system reflecting higher efficiency as a

  12. Sea-ice melt CO2-carbonate chemistry in the western Arctic Ocean: meltwater contributions to air-sea CO2 gas exchange, mixed layer properties and rates of net community production under sea ice

    Science.gov (United States)

    Bates, N. R.; Garley, R.; Frey, K. E.; Shake, K. L.; Mathis, J. T.

    2014-01-01

    The carbon dioxide (CO2)-carbonate chemistry of sea-ice melt and co-located, contemporaneous seawater has rarely been studied in sea ice covered oceans. Here, we describe the CO2-carbonate chemistry of sea-ice melt (both above sea ice as "melt ponds" and below sea ice as "interface waters") and mixed layer properties in the western Arctic Ocean in the early summer of 2010 and 2011. At nineteen stations, the salinity (~ 0.5 to 1500 μatm) with the majority of melt ponds acting as potentially strong sources of CO2 to the atmosphere. The pH of melt pond waters was also highly variable ranging from mildly acidic (6.1 to 7) to slightly more alkaline than underlying seawater (8 to 10.7). All of observed melt ponds had very low (pH/Ωaragonite than the co-located mixed layer beneath. Sea-ice melt thus contributed to the suppression of mixed layer pCO2 enhancing the surface ocean's capacity to uptake CO2 from the atmosphere. Meltwater contributions to changes in mixed-layer DIC were also used to estimate net community production rates (mean of 46.9 ±29.8 g C m-2 for the early-season period) under sea-ice cover. Although sea-ice melt is a transient seasonal feature, above-ice melt pond coverage can be substantial (10 to > 50%) and under-ice interface melt water is ubiquitous during this spring/summer sea-ice retreat. Our observations contribute to growing evidence that sea-ice CO2-carbonate chemistry is highly variable and its contribution to the complex factors that influence the balance of CO2 sinks and sources (and thereby ocean acidification) is difficult to predict in an era of rapid warming and sea ice loss in the Arctic Ocean.

  13. Net ecosystem calcification and net primary production in two Hawaii back-reef systems

    Science.gov (United States)

    Kiili, S.; Colbert, S.; Hart, K.

    2016-02-01

    Back-reef systems have complex carbon cycling, driven by dominant benthic communities that change with environmental conditions and display characteristic patterns of net primary production (NP) and net ecosystem calcification (G). The G/NP ratio provides a fundamental community-level assessment to compare systems spatially and to evaluate temporal changes in carbon cycling. Carbon dynamics were examined at leeward Hōnaunau and windward Waíōpae, Hawaíi Island. Both locations discharge brackish groundwater, including geothermal water at Waíōpae. The change in total CO2 (TCO2) and total alkalinity (TA) between morning and afternoon was measured to calculate the G/NP ratio along a salinity gradient. At both sites, aragonite saturation (ΩAr) was lower than open ocean conditions, and increased with salinity. Between the morning and afternoon, ΩAr increased by at least 1 as photosynthesis consumed CO2. At Waíōpae, water was corrosive to aragonite due to the input of acidic groundwater, but not at Honaunau, demonstrating the importance of local watershed characteristics on ΩAr. Across the salinity gradient, TA and TCO2 decreased between morning and afternoon. At Hōnaunau, G/NP increased from 0.11 to 0.31 with salinity, consistent with an offshore increase in coral cover. But at Waíōpae, G/NP decreased from 0.49 to 0.0 with salinity, despite an increase in coral cover with salinity. Low G may be caused by benthic processes, including coral bleaching or high rates of carbonate dissolution in interstitial waters between tide pools. Broader environmental conditions than just salinity, including pH of fresh groundwater inputs, shape the carbon cycling in the back-reef system. Examining the G/NP ratio of a back-reef system allows for a simple method to establish community level activity, and possibly indicate changes in a dynamic system.

  14. Forest and grassland cover types reduce net greenhouse gas emissions from agricultural soils.

    Science.gov (United States)

    Baah-Acheamfour, Mark; Carlyle, Cameron N; Lim, Sang-Sun; Bork, Edward W; Chang, Scott X

    2016-11-15

    Western Canada's prairie region is extensively cultivated for agricultural production, which is a large source of greenhouse gas emissions. Agroforestry systems are common land uses across Canada, which integrate trees into the agricultural landscape and could play a substantial role in sequestering carbon and mitigating increases in atmospheric GHG concentrations. We measured soil CO2, CH4 and N2O fluxes and the global warming potential of microbe-mediated net greenhouse gas emissions (GWPm) in forest and herbland (areas without trees) soils of three agroforestry systems (hedgerow, shelterbelt and silvopasture) over two growing seasons (May through September in 2013 and 2014). We measured greenhouse gas fluxes and environmental conditions at 36 agroforestry sites (12 sites for each system) located along a south-north oriented soil/climate gradient of increasing moisture availability in central Alberta, Canada. The temperature sensitivity of soil CO2 emissions was greater in herbland (4.4) than in forest (3.1), but was not different among agroforestry systems. Over the two seasons, forest soils had 3.4% greater CO2 emission, 36% higher CH4 uptake, and 66% lower N2O emission than adjacent herbland soils. Combining the CO2 equivalents of soil CH4 and N2O fluxes with the CO2 emitted via heterotrophic (microbial) respiration, forest soils had a smaller GWPm than herbland soils (68 and 89kgCO2ha(-1), respectively). While emissions of total CO2 were silvopasture>hedgerow>shelterbelt, soils under silvopasture had 5% lower heterotrophic respiration, 15% greater CH4 uptake, and 44% lower N2O emission as compared with the other two agroforestry systems. Overall, the GWPm of greenhouse gas emissions was greater in hedgerow (88) and shelterbelt (85) than in the silvopasture system (76kgCO2ha(-1)). High GWPm in the hedgerow and shelterbelt systems reflects the greater contribution from the monoculture annual crops within these systems. Opportunities exist for reducing soil

  15. Net ecosystem productivity, net primary productivity and ecosystem carbon sequestration in a Pinus radiata plantation subject to soil water deficit

    Energy Technology Data Exchange (ETDEWEB)

    Arneth, A.; Kelleher, F. M. [Lincoln Univ., Soil Sience Dept., Lincoln, (New Zealand); McSeveny, T. M. [Manaaki Whenua-Landcare Research, Lincoln, (New Zealand); Byers, J. N. [Almuth Arneth Landcare Research, Lincoln (New Zealand)

    1998-12-01

    Tree carbon uptake (net primary productivity excluding fine root turnover, NPP`) in pine trees growing in a region of New Zealand subject to summer soil water deficit was investigated jointly with canopy assimilation (A{sub c}) and ecosystem-atmosphere carbon exchange rate (net ecosystem productivity, NEP). Canopy assimilation and NEP were used to drive a biochemically-based and environmentally constrained model validated by seasonal eddy covariance measurements. Over a three year period with variable rainfall annual NPP` and NEP showed significant variations. At the end of the growing season, carbon was mostly allocated to wood, with nearly half to stems and about a quarter to coarse roots. On a biweekly basis NPP` lagged behind A{sub c}, suggesting the occurrence of intermediate carbon storage. On an annual basis, however the NPP`/A{sub c} ratio indicated a conservative allocation of carbon to autotrophic respiration. The combination of data from measurements with canopy and ecosystem carbon fluxes yielded an estimate of heterotrophic respiration (NPP`-NEP) of approximately 30 per cent of NPP` and 50 per cent NEP. The annual values of NEP and NPP` can also be used to derive a `best guess` estimate of the annual below-ground carbon turnover rate, assuming that the annual changes in the soil carbon content is negligible. 46 refs., 7 figs.

  16. HANPP Collection: Global Patterns in Human Appropriation of Net Primary Productivity (HANPP)

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Patterns in Human Appropriation of Net Primary Productivity (HANPP) portion of the HANPP Collection represents a digital map of human appropriation of net...

  17. Effects of gas composition in headspace and bicarbonate concentrations in media on gas and methane production, degradability, and rumen fermentation using in vitro gas production techniques.

    Science.gov (United States)

    Patra, Amlan Kumar; Yu, Zhongtang

    2013-07-01

    Headspace gas composition and bicarbonate concentrations in media can affect methane production and other characteristics of rumen fermentation in in vitro gas production systems, but these 2 important factors have not been evaluated systematically. In this study, these 2 factors were investigated with respect to gas and methane production, in vitro digestibility of feed substrate, and volatile fatty acid (VFA) profile using in vitro gas production techniques. Three headspace gas compositions (N2+ CO2+ H2 in the ratio of 90:5:5, CO2, and N2) with 2 substrate types (alfalfa hay only, and alfalfa hay and a concentrate mixture in a 50:50 ratio) in a 3×2 factorial design (experiment 1) and 3 headspace compositions (N2, N2 + CO2 in a 50:50 ratio, and CO2) with 3 bicarbonate concentrations (80, 100, and 120 mM) in a 3×3 factorial design (experiment 2) were evaluated. In experiment 1, total gas production (TGP) and net gas production (NGP) was the lowest for CO2, followed by N2, and then the gas mixture. Methane concentration in headspace gas after fermentation was greater for CO2 than for N2 and the gas mixture, whereas total methane production (TMP) and net methane production (NMP) were the greatest for CO2, followed by the gas mixture, and then N2. Headspace composition did not affect in vitro digestibility or the VFA profile, except molar percentages of propionate, which were greater for CO2 and N2 than for the gas mixture. Methane concentration in headspace gas, TGP, and NGP were affected by the interaction of headspace gas composition and substrate type. In experiment 2, increasing concentrations of CO2 in the headspace decreased TGP and NGP quadratically, but increased the concentrations of methane, NMP, and in vitro fiber digestibility linearly, and TMP quadratically. Fiber digestibility, TGP, and NGP increased linearly with increasing bicarbonate concentrations in the medium. Concentrations of methane and NMP were unaffected by bicarbonate concentration, but

  18. Ozone and haze pollution weakens net primary productivity in China

    Science.gov (United States)

    Yue, Xu; Unger, Nadine; Harper, Kandice; Xia, Xiangao; Liao, Hong; Zhu, Tong; Xiao, Jingfeng; Feng, Zhaozhong; Li, Jing

    2017-05-01

    Atmospheric pollutants have both beneficial and detrimental effects on carbon uptake by land ecosystems. Surface ozone (O3) damages leaf photosynthesis by oxidizing plant cells, while aerosols promote carbon uptake by increasing diffuse radiation and exert additional influences through concomitant perturbations to meteorology and hydrology. China is currently the world's largest emitter of both carbon dioxide and short-lived air pollutants. The land ecosystems of China are estimated to provide a carbon sink, but it remains unclear whether air pollution acts to inhibit or promote carbon uptake. Here, we employ Earth system modeling and multiple measurement datasets to assess the separate and combined effects of anthropogenic O3 and aerosol pollution on net primary productivity (NPP) in China. In the present day, O3 reduces annual NPP by 0.6 Pg C (14 %) with a range from 0.4 Pg C (low O3 sensitivity) to 0.8 Pg C (high O3 sensitivity). In contrast, aerosol direct effects increase NPP by 0.2 Pg C (5 %) through the combination of diffuse radiation fertilization, reduced canopy temperatures, and reduced evaporation leading to higher soil moisture. Consequently, the net effects of O3 and aerosols decrease NPP by 0.4 Pg C (9 %) with a range from 0.2 Pg C (low O3 sensitivity) to 0.6 Pg C (high O3 sensitivity). However, precipitation inhibition from combined aerosol direct and indirect effects reduces annual NPP by 0.2 Pg C (4 %), leading to a net air pollution suppression of 0.8 Pg C (16 %) with a range from 0.6 Pg C (low O3 sensitivity) to 1.0 Pg C (high O3 sensitivity). Our results reveal strong dampening effects of air pollution on the land carbon uptake in China today. Following the current legislation emission scenario, this suppression will be further increased by the year 2030, mainly due to a continuing increase in surface O3. However, the maximum technically feasible reduction scenario could drastically relieve the current level of NPP damage by 70 % in 2030

  19. Decreases in net primary production and net ecosystem production along a repeated-fires induced forest/grassland gradient

    Science.gov (United States)

    Cheng, C. H.; Huang, Y. H.; Chung-Yu, L.; Menyailo, O.

    2016-12-01

    Fire is one of the most important disturbances in ecosystems. Fire rapidly releases stored carbon into atmosphere and also plays critical roles on soil properties, light and moisture regimes, and plant structures and communities. With the interventions of climate change and human activities, fire regimes become more severe and frequent. In many parts of world, forest fire regimes can be further altered by grass invasion because the invasive grasses create a positive feedback cycle through their rapid recovery after fires and their high flammability during dry periods and allow forests to be burned repeatedly in a relatively short time. For such invasive grass-fire cycle, a great change of native vegetation community can occur. In this study, we examined a C4 invasive grass () fire-induced forest/grassland gradient to quantify the changes of net primary production (NPP) and net ecosystem production (NEP) from an unburned forest to repeated fire grassland. Our results demonstrated negative effects of repeated fires on NPP and NEP. Within 4 years of the onset of repeated fires on the unburned forest, NPP declined by 14%, mainly due to the reduction in aboveground NPP but offset by increase of belowground NPP. Subsequent fires cumulatively caused reductions in both aboveground and belowground NPP. A total of 40% reduction in the long-term repeated fire induced grassland was found. Soil respiration rate were not significantly different along the forest/grassland gradient. Thus, a great reduction in NEP were shown in grassland, which shifted from 4.6 Mg C ha-1 yr-1 in unburnt forest to -2.6 Mg C ha-1 yr-1. Such great losses are critical within the context of forest carbon cycling and long-term sustainability. Forest management practices that can effectively reduce the likelihood of repeated fires and consequent likelihood of establishment of the grass fire cycle are essential for protecting the forest.

  20. Gross nitrous oxide production drives net nitrous oxide fluxes across a salt marsh landscape.

    Science.gov (United States)

    Yang, Wendy H; Silver, Whendee L

    2016-06-01

    Sea level rise will change inundation regimes in salt marshes, altering redox dynamics that control nitrification - a potential source of the potent greenhouse gas, nitrous oxide (N2 O) - and denitrification, a major nitrogen (N) loss pathway in coastal ecosystems and both a source and sink of N2 O. Measurements of net N2 O fluxes alone yield little insight into the different effects of redox conditions on N2 O production and consumption. We used in situ measurements of gross N2 O fluxes across a salt marsh elevation gradient to determine how soil N2 O emissions in coastal ecosystems may respond to future sea level rise. Soil redox declined as marsh elevation decreased, with lower soil nitrate and higher ferrous iron in the low marsh compared to the mid and high marshes (P < 0.001 for both). In addition, soil oxygen concentrations were lower in the low and mid-marshes relative to the high marsh (P < 0.001). Net N2 O fluxes differed significantly among marsh zones (P = 0.009), averaging 9.8 ± 5.4 μg N m(-2)  h(-1) , -2.2 ± 0.9 μg N m(-2)  h(-1) , and 0.67 ± 0.57 μg N m(-2)  h(-1) in the low, mid, and high marshes, respectively. Both net N2 O release and uptake were observed in the low and high marshes, but the mid-marsh was consistently a net N2 O sink. Gross N2 O production was highest in the low marsh and lowest in the mid-marsh (P = 0.02), whereas gross N2 O consumption did not differ among marsh zones. Thus, variability in gross N2 O production rates drove the differences in net N2 O flux among marsh zones. Our results suggest that future studies should focus on elucidating controls on the processes producing, rather than consuming, N2 O in salt marshes to improve our predictions of changes in net N2 O fluxes caused by future sea level rise. © 2015 John Wiley & Sons Ltd.

  1. Comparing the Net Ecosystem Exchange of Two Cropping Systems for Dairy Feed Production

    Science.gov (United States)

    Sulaiman, M. F.; Wagner-Riddle, C.; Brown, S. E.

    2015-12-01

    A three-year study was conducted from 2012 to 2014 to determine the net CO2 fluxes from corn and hay, the two main feed crops used in dairy production. The aim of this study is to better understand the net ecosystem exchange (NEE) in annual and perennial cropping systems used in dairy production to benefit greenhouse gas emission model developments and the life cycle analysis of dairy production. The study was conducted on two 4-ha plots where one plot was a 5-year old hayfield and the other plot was planted in a continuous cycle corn. All plots were continuously monitored using the flux-gradient method deployed with a tunable diode laser trace gas analyzer and sonic anemometers. All plots received dairy manure as fertilizer applied according to common practice. The cumulative NEE for the three years of the study was -873.15 g C m-2 for corn and -409.36 g C m-2 for hay. Differences in respiration between the two cropping systems was found to be the larger factor compared to differences in gross ecosystem production (GEP) that resulted in the contrasting cumulative NEE where cumulative respiration for the three years for hay was 3094.23 g C m-2 as opposed to 2078.11 g C m-2 for corn. Cumulative GEP for the three years was 3503.60 and 2951.31 g C m-2 for hay and corn respectively. Inter-annual and inter-crop variability of the NEE, GEP and respiration will be discussed in relation to biomass production, climatic conditions and crop physiological characteristics.

  2. Scaling net ecosystem production and net biome production over a heterogeneous region in the western United States

    Directory of Open Access Journals (Sweden)

    D. P. Turner

    2007-08-01

    Full Text Available Bottom-up scaling of net ecosystem production (NEP and net biome production (NBP was used to generate a carbon budget for a large heterogeneous region (the state of Oregon, 2.5×105 km2 in the western United States. Landsat resolution (30 m remote sensing provided the basis for mapping land cover and disturbance history, thus allowing us to account for all major fire and logging events over the last 30 years. For NEP, a 23-year record (1980–2002 of distributed meteorology (1 km resolution at the daily time step was used to drive a process-based carbon cycle model (Biome-BGC. For NBP, fire emissions were computed from remote sensing based estimates of area burned and our mapped biomass estimates. Our estimates for the contribution of logging and crop harvest removals to NBP were from the model simulations and were checked against public records of forest and crop harvesting. The predominately forested ecoregions within our study region had the highest NEP sinks, with ecoregion averages up to 197 gC m−2 yr−1. Agricultural ecoregions were also NEP sinks, reflecting the imbalance of NPP and decomposition of crop residues. For the period 1996–2000, mean NEP for the study area was 17.0 TgC yr−1, with strong interannual variation (SD of 10.6. The sum of forest harvest removals, crop removals, and direct fire emissions amounted to 63% of NEP, leaving a mean NBP of 6.1 TgC yr−1. Carbon sequestration was predominantly on public forestland, where the harvest rate has fallen dramatically in the recent years. Comparison of simulation results with estimates of carbon stocks, and changes in carbon stocks, based on forest inventory data showed generally good agreement. The carbon sequestered as NBP, plus accumulation of forest products in slow turnover pools, offset 51% of the annual emissions of fossil fuel CO2 for the state. State-level NBP dropped below zero in 2002

  3. Scaling net ecosystem production and net biome production over a heterogeneous region in the western United States

    Science.gov (United States)

    Turner, D. P.; Ritts, W. D.; Law, B. E.; Cohen, W. B.; Yang, Z.; Hudiburg, T.; Campbell, J. L.; Duane, M.

    2007-08-01

    Bottom-up scaling of net ecosystem production (NEP) and net biome production (NBP) was used to generate a carbon budget for a large heterogeneous region (the state of Oregon, 2.5×105 km2) in the western United States. Landsat resolution (30 m) remote sensing provided the basis for mapping land cover and disturbance history, thus allowing us to account for all major fire and logging events over the last 30 years. For NEP, a 23-year record (1980-2002) of distributed meteorology (1 km resolution) at the daily time step was used to drive a process-based carbon cycle model (Biome-BGC). For NBP, fire emissions were computed from remote sensing based estimates of area burned and our mapped biomass estimates. Our estimates for the contribution of logging and crop harvest removals to NBP were from the model simulations and were checked against public records of forest and crop harvesting. The predominately forested ecoregions within our study region had the highest NEP sinks, with ecoregion averages up to 197 gC m-2 yr-1. Agricultural ecoregions were also NEP sinks, reflecting the imbalance of NPP and decomposition of crop residues. For the period 1996-2000, mean NEP for the study area was 17.0 TgC yr-1, with strong interannual variation (SD of 10.6). The sum of forest harvest removals, crop removals, and direct fire emissions amounted to 63% of NEP, leaving a mean NBP of 6.1 TgC yr-1. Carbon sequestration was predominantly on public forestland, where the harvest rate has fallen dramatically in the recent years. Comparison of simulation results with estimates of carbon stocks, and changes in carbon stocks, based on forest inventory data showed generally good agreement. The carbon sequestered as NBP, plus accumulation of forest products in slow turnover pools, offset 51% of the annual emissions of fossil fuel CO2 for the state. State-level NBP dropped below zero in 2002 because of the combination of a dry climate year and a large (200 000 ha) fire. These results highlight

  4. Can Switching from Coal to Shale Gas Bring Net Carbon Reductions to China?

    Science.gov (United States)

    Qin, Yue; Edwards, Ryan; Tong, Fan; Mauzerall, Denise L

    2017-03-07

    To increase energy security and reduce emissions of air pollutants and CO2 from coal use, China is attempting to duplicate the rapid development of shale gas that has taken place in the United States. This work builds a framework to estimate the lifecycle greenhouse gas (GHG) emissions from China's shale gas system and compares them with GHG emissions from coal used in the power, residential, and industrial sectors. We find the mean lifecycle carbon footprint of shale gas is about 30-50% lower than that of coal in all sectors under both 20 year and 100 year global warming potentials (GWP20 and GWP100). However, primarily due to large uncertainties in methane leakage, the upper bound estimate of the lifecycle carbon footprint of shale gas in China could be approximately 15-60% higher than that of coal across sectors under GWP20. To ensure net GHG emission reductions when switching from coal to shale gas, we estimate the breakeven methane leakage rates to be approximately 6.0%, 7.7%, and 4.2% in the power, residential, and industrial sectors, respectively, under GWP20. We find shale gas in China has a good chance of delivering air quality and climate cobenefits, particularly when used in the residential sector, with proper methane leakage control.

  5. Caspian Oil and Gas: Production and Prospects

    National Research Council Canada - National Science Library

    Gelb, Bernard A

    2005-01-01

    .... The Caspian Sea region historically has been an oil and natural gas producer, but many believe that the region contains large reserves of oil and gas capable of much greater production than at present...

  6. Spatial scaling of net primary productivity using subpixel landcover information

    Science.gov (United States)

    Chen, X. F.; Chen, Jing M.; Ju, Wei M.; Ren, L. L.

    2008-10-01

    Gridding the land surface into coarse homogeneous pixels may cause important biases on ecosystem model estimations of carbon budget components at local, regional and global scales. These biases result from overlooking subpixel variability of land surface characteristics. Vegetation heterogeneity is an important factor introducing biases in regional ecological modeling, especially when the modeling is made on large grids. This study suggests a simple algorithm that uses subpixel information on the spatial variability of land cover type to correct net primary productivity (NPP) estimates, made at coarse spatial resolutions where the land surface is considered as homogeneous within each pixel. The algorithm operates in such a way that NPP obtained from calculations made at coarse spatial resolutions are multiplied by simple functions that attempt to reproduce the effects of subpixel variability of land cover type on NPP. Its application to a carbon-hydrology coupled model(BEPS-TerrainLab model) estimates made at a 1-km resolution over a watershed (named Baohe River Basin) located in the southwestern part of Qinling Mountains, Shaanxi Province, China, improved estimates of average NPP as well as its spatial variability.

  7. Modeling and Optimizing Energy Utilization of Steel Production Process: A Hybrid Petri Net Approach

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2013-01-01

    Full Text Available The steel industry is responsible for nearly 9% of anthropogenic energy utilization in the world. It is urgent to reduce the total energy utilization of steel industry under the huge pressures on reducing energy consumption and CO2 emission. Meanwhile, the steel manufacturing is a typical continuous-discrete process with multiprocedures, multiobjects, multiconstraints, and multimachines coupled, which makes energy management rather difficult. In order to study the energy flow within the real steel production process, this paper presents a new modeling and optimization method for the process based on Hybrid Petri Nets (HPN in consideration of the situation above. Firstly, we introduce the detailed description of HPN. Then the real steel production process from one typical integrated steel plant is transformed into Hybrid Petri Net model as a case. Furthermore, we obtain a series of constraints of our optimization model from this model. In consideration of the real process situation, we pick the steel production, energy efficiency and self-made gas surplus as the main optimized goals in this paper. Afterwards, a fuzzy linear programming method is conducted to obtain the multiobjective optimization results. Finally, some measures are suggested to improve this low efficiency and high whole cost process structure.

  8. Shale gas production: potential versus actual greenhouse gas emissions

    OpenAIRE

    O'Sullivan, Francis Martin; Paltsev, Sergey

    2012-01-01

    Estimates of greenhouse gas (GHG) emissions from shale gas production and use are controversial. Here we assess the level of GHG emissions from shale gas well hydraulic fracturing operations in the United States during 2010. Data from each of the approximately 4000 horizontal shale gas wells brought online that year are used to show that about 900 Gg CH[subscript 4] of potential fugitive emissions were generated by these operations, or 228 Mg CH[subscript 4] per well—a figure inappropriately ...

  9. MODIS/Terra Net Primary Production Yearly L4 Global 500m SIN Grid V006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MOD17A3H Version 6 product provides information about annual (yearly) Net Primary Production at 500 meter pixel resolution. Annual NPP is derived from the sum of...

  10. MODIS/Aqua Net Primary Production Yearly L4 Global 500m SIN Grid V006

    Data.gov (United States)

    National Aeronautics and Space Administration — The MYD17A3H Version 6 product provides information about annual (yearly) Net Primary Production at 500 meter pixel resolution. Annual NPP is derived from the sum of...

  11. Energy intensity ratios as net energy measures of United States energy production and expenditures

    Science.gov (United States)

    King, C. W.

    2010-10-01

    In this letter I compare two measures of energy quality, energy return on energy invested (EROI) and energy intensity ratio (EIR) for the fossil fuel consumption and production of the United States. All other characteristics being equal, a fuel or energy system with a higher EROI or EIR is of better quality because more energy is provided to society. I define and calculate the EIR for oil, natural gas, coal, and electricity as measures of the energy intensity (units of energy divided by money) of the energy resource relative to the energy intensity of the overall economy. EIR measures based upon various unit prices for energy (e.g. /Btu of a barrel of oil) as well as total expenditures on energy supplies (e.g. total dollars spent on petroleum) indicate net energy at different points in the supply chain of the overall energy system. The results indicate that EIR is an easily calculated and effective proxy for EROI for US oil, gas, coal, and electricity. The EIR correlates well with previous EROI calculations, but adds additional information on energy resource quality within the supply chain. Furthermore, the EIR and EROI of oil and gas as well as coal were all in decline for two time periods within the last 40 years, and both time periods preceded economic recessions.

  12. Whole Farm Net Greenhouse Gas Abatement from Establishing Kikuyu-Based Perennial Pastures in South-Western Australia

    Directory of Open Access Journals (Sweden)

    David G. Masters

    2012-08-01

    Full Text Available On-farm activities that reduce GHG emissions or sequester carbon from the atmosphere to compensate for anthropogenic emissions are currently being evaluated by the Australian Government as carbon offset opportunities. The aim of this study was to examine the implications of establishing and grazing Kikuyu pastures, integrated as part of a mixed Merino sheep and cropping system, as a carbon offset mechanism. For the assessment of changes in net greenhouse gas emissions, results from a combination of whole farm economic and livestock models were used (MIDAS and GrassGro. Net GHG emissions were determined by deducting increased emissions from introducing this practice change (increased methane and nitrous oxide emissions due to higher stocking rates from the soil carbon sequestered from growing the Kikuyu pasture. Our results indicate that livestock systems using perennial pastures may have substantially lower net GHG emissions, and reduced GHG intensity of production, compared with annual plant-based production systems. Soil carbon accumulation by converting 45% of arable land within a farm enterprise to Kikuyu-based pasture was determined to be 0.80 t CO2-e farm ha−1 yr−1 and increased GHG emissions (leakage was 0.19 t CO2-e farm ha−1 yr−1. The net benefit of this practice change was 0.61 t CO2-e farm ha−1 yr−1 while the rate of soil carbon accumulation remains constant. The use of perennial pastures improved the efficiency of animal production almost eight fold when expressed as carbon dioxide equivalent emissions per unit of animal product. The strategy of using perennial pasture to improve production levels and store additional carbon in the soil demonstrates how livestock should be considered in farming systems as both sources and sinks for GHG abatement.

  13. Why Net Domestic Product Should Replace Gross Domestic Product as a Measure of Economic Growth

    OpenAIRE

    Roland Spant

    2003-01-01

    In the third article, Roland Spant, a Swedish trade union economist, argues that Net Domestic Product (NDP) should replace GDP as a measure of economic growth for a number of purposes. The key difference between GDP and NDP is depreciation. With the shift in investment toward information technology assets with relatively short service lives, the share of depreciation in GDP has increased in most OECD countries and GDP growth now exceeds NDP growth. Spant points out that this means that the us...

  14. Comparison of net global warming potential and greenhouse gas intensity affected by management practices in two dryland cropping sites

    Science.gov (United States)

    Little is known about the effect of management practices on net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of greenhouse gas (GHG) emissions in dryland cropping systems. The objective of this study was to compare the effect of a combinat...

  15. Effects of climate change and shifts in forest composition on forest net primary production

    Science.gov (United States)

    Jyh-Min Chiang; Louts [Louis] R. Iverson; Anantha Prasad; Kim J. Brown

    2008-01-01

    Forests are dynamic in both structure and species composition, and these dynamics are strongly influenced by climate. However, the net effects of future tree species composition on net primary production (NPP) are not well understood. The objective of this work was to model the potential range shifts of tree species (DISTRIB Model) and predict their impacts on NPP (...

  16. Flood effects on efflux and net production of nitrous oxide in river floodplain soils

    Science.gov (United States)

    Riaz, Muhammad; Bruderer, Christian; Niklaus, Pascal A.; Luster, Jörg

    2016-04-01

    Floodplain soils are often rich in nutrients and exhibit high spatial heterogeneity in terms of geomorphology, soil environmental conditions and substrate availability for processes involved in carbon and nutrient cycling. In addition, fluctuating water tables lead to temporally changing redox conditions. In such systems, there are ideal conditions for the occurrence of hot spots and moments of nitrous oxide emissions, a potent greenhouse gas. The factors that govern the spatial heterogeneity and dynamics of N2O formation in floodplain soils and the surface efflux of this gas are not fully understood. A particular issue is the contribution of N2O formation in the subsoil to surface efflux. We studied this question in the floodplain of a restored section of the Thur river (NE Switzerland) which is characterized by a flashy flow regime. As a consequence, the floodplain soils are unsaturated most of the time. We showed earlier that saturation during flood pulses leads to short phases of generally anoxic conditions followed by a drying phase with anoxic conditions within aggregates and oxic conditions in larger soil pores. The latter conditions are conducive for spatially closely-coupled nitrification-denitrification and related hot moments of nitrous oxide formation. In a floodplain zone characterized by about one meter of young, sandy sediments, that are mostly covered by the tall grass Phalaris arundinacea, we measured at several time points before and after a small flood event N2O surface efflux with the closed-chamber method, and assessed N2O concentrations in the soil air at four different depths using gas-permeable tubings. In addition, we calculated the N2O diffusivity in the soil from Radon diffusivity. The latter was estimated in-situ from the recovery of Radon concentration in the gas-permeable tubings after purging with ambient air. All these data were then used to calculate net N2O production rates at different soil depths with the gradient method. In

  17. Net community production at Ocean Station Papa observed with nitrate and oxygen sensors on profiling floats

    Science.gov (United States)

    Plant, Joshua N.; Johnson, Kenneth S.; Sakamoto, Carole M.; Jannasch, Hans W.; Coletti, Luke J.; Riser, Stephen C.; Swift, Dana D.

    2016-06-01

    Six profiling floats equipped with nitrate and oxygen sensors were deployed at Ocean Station P in the Gulf of Alaska. The resulting six calendar years and 10 float years of nitrate and oxygen data were used to determine an average annual cycle for net community production (NCP) in the top 35 m of the water column. NCP became positive in February as soon as the mixing activity in the surface layer began to weaken, but nearly 3 months before the traditionally defined mixed layer began to shoal from its winter time maximum. NCP displayed two maxima, one toward the end of May and another in August with a summertime minimum in June corresponding to the historical peak in mesozooplankton biomass. The average annual NCP was determined to be 1.5 ± 0.6 mol C m-2 yr-1 using nitrate and 1.5 ± 0.7 mol C m-2 yr-1 using oxygen. The results from oxygen data proved to be quite sensitive to the gas exchange model used as well as the accuracy of the oxygen measurement. Gas exchange models optimized for carbon dioxide flux generally ignore transport due to gas exchange through the injection of bubbles, and these models yield NCP values that are two to three time higher than the nitrate-based estimates. If nitrate and oxygen NCP rates are assumed to be related by the Redfield model, we show that the oxygen gas exchange model can be optimized by tuning the exchange terms to reproduce the nitrate NCP annual cycle.

  18. COST OF PRODUCTION, GROSS RETURN AND NET PROFIT IN COMMERCIAL EGG PRODUCTION

    Directory of Open Access Journals (Sweden)

    M. Farooq, Zahoor-ul-Haq1, M.A. Mian, F.R. Durrani and M. Syed

    2003-01-01

    Full Text Available The present study was carried out in Chakwal, Pakistan by collecting data from randomly selected 109 flocks to investigate cost of production, gross return and net profit per layer. Majority of the buildings in the study area were rented therefore, rent per layer was added to the total cost of production instead of depreciation on building and equipments. Overall total cost of production, gross return and net profit per layer was Rs. 393.88 ± 5.36, 432.14 ± 8.01 and 38.26 ± 6.66, respectively. Rate of return over the invested capital was 27%. Mean feed cost per layer was Rs. 302.23 ± 5.01, including Rs. 10.27 ± 0.24, 29.19 ± 0.42 and 262.77 ± 5.08 for starter, grower and layer ration, respectively. Feed cost was the major component contributing 76.73% to the total cost of production. Average cost of labor, day-old chick, building rent, vaccination, therapy, miscellaneous item, electricity, bedding material and transportation was Rs. 19.90 ± 0.45, 19.75 ± 0.05, 16.25 ± 0.26, 12.80 ± 0.10, 10.90 ± 2.32, 4.35 ± 0.09, 3.15 ± 0.07, 2.65 ± 0.09 and 1.90 ± 0.08, respectively, contributing 5.05, 5.01, 4.13, 3.25, 2.77, 1.10, 0.80, 0.67 and 0.48 % to the total cost of production. Gross return from the sale of marketable eggs, culled eggs, spent/culled bird, empty bags and manure was Rs. 388.84 ± 7.91, 3.85 ± 0.01, 35.80 ± 0.23, 2.20 ± 0.04 and 1.45 ± 0.01, respectively, contributing 89.98, 0.89, 8.28, 0.51 and 0.34% to the total return. Determining the effect of different parameters on the cost of production and net profit, large flocks, Hisex strain, brood-grow and lay system of rearing, good hygienic conditions of the farm, normal stocking rate and cage system of housing wee found to give maximum gross return as well as net profit.

  19. Daily variation in net primary production and net calcification in coral reef communities exposed to elevated pCO2

    Science.gov (United States)

    Comeau, Steeve; Edmunds, Peter J.; Lantz, Coulson A.; Carpenter, Robert C.

    2017-07-01

    The threat represented by ocean acidification (OA) for coral reefs has received considerable attention because of the sensitivity of calcifiers to changing seawater carbonate chemistry. However, most studies have focused on the organismic response of calcification to OA, and only a few have addressed community-level effects, or investigated parameters other than calcification, such as photosynthesis. Light (photosynthetically active radiation, PAR) is a driver of biological processes on coral reefs, and the possibility that these processes might be perturbed by OA has important implications for community function. Here we investigate how CO2 enrichment affects the relationships between PAR and community net O2 production (Pnet), and between PAR and community net calcification (Gnet), using experiments on three coral communities constructed to match (i) the back reef of Mo'orea, French Polynesia, (ii) the fore reef of Mo'orea, and (iii) the back reef of O'ahu, Hawaii. The results were used to test the hypothesis that OA affects the relationship between Pnet and Gnet. For the three communities tested, pCO2 did not affect the Pnet-PAR relationship, but it affected the intercept of the hyperbolic tangent curve fitting the Gnet-PAR relationship for both reef communities in Mo'orea (but not in O'ahu). For the three communities, the slopes of the linear relationships between Pnet and Gnet were not affected by OA, although the intercepts were depressed by the inhibitory effect of high pCO2 on Gnet. Our result indicates that OA can modify the balance between net calcification and net photosynthesis of reef communities by depressing community calcification, but without affecting community photosynthesis.

  20. Daily variation in net primary production and net calcification in coral reef communities exposed to elevated pCO2

    Directory of Open Access Journals (Sweden)

    S. Comeau

    2017-07-01

    Full Text Available The threat represented by ocean acidification (OA for coral reefs has received considerable attention because of the sensitivity of calcifiers to changing seawater carbonate chemistry. However, most studies have focused on the organismic response of calcification to OA, and only a few have addressed community-level effects, or investigated parameters other than calcification, such as photosynthesis. Light (photosynthetically active radiation, PAR is a driver of biological processes on coral reefs, and the possibility that these processes might be perturbed by OA has important implications for community function. Here we investigate how CO2 enrichment affects the relationships between PAR and community net O2 production (Pnet, and between PAR and community net calcification (Gnet, using experiments on three coral communities constructed to match (i the back reef of Mo'orea, French Polynesia, (ii the fore reef of Mo'orea, and (iii the back reef of O'ahu, Hawaii. The results were used to test the hypothesis that OA affects the relationship between Pnet and Gnet. For the three communities tested, pCO2 did not affect the Pnet–PAR relationship, but it affected the intercept of the hyperbolic tangent curve fitting the Gnet–PAR relationship for both reef communities in Mo'orea (but not in O'ahu. For the three communities, the slopes of the linear relationships between Pnet and Gnet were not affected by OA, although the intercepts were depressed by the inhibitory effect of high pCO2 on Gnet. Our result indicates that OA can modify the balance between net calcification and net photosynthesis of reef communities by depressing community calcification, but without affecting community photosynthesis.

  1. Residence time control on hot moments of net nitrate production and uptake in the hyporheic zone

    Science.gov (United States)

    Briggs, Martin A.; Lautz, Laura K.; Hare, Danielle K.

    2014-01-01

    The retention capacity for biologically available nitrogen within streams can be influenced by dynamic hyporheic zone exchange, a process that may act as either a net source or net sink of dissolved nitrogen. Over 5 weeks, nine vertical profiles of streambed chemistry (NO3- and NH4+) were collected above two beaver dams along with continuous high-resolution vertical hyporheic flux data. The results indicate a non-linear relation of net NO3- production followed by net uptake in the hyporheic zone as a function of residence time. This Lagrangian-based relation is consistent through time and across varied morphology (bars, pools, glides) above the dams, even though biogeochemical and environmental factors varied. The empirical continuum between net NO3- production and uptake and residence time is useful for identifying two crucial residence time thresholds: the transition to anaerobic respiration, which corresponds to the time of peak net nitrate production, and the net sink threshold, which is defined by a net uptake in NO3- relative to streamwater. Short-term hyporheic residence time variability at specific locations creates hot

  2. ConocoPhillips Gas Hydrate Production Test

    Energy Technology Data Exchange (ETDEWEB)

    Schoderbek, David [ConocoPhillips Co., Houston, TX (United States); Farrell, Helen [ConocoPhillips Co., Houston, TX (United States); Howard, James [ConocoPhillips Co., Houston, TX (United States); Raterman, Kevin [ConocoPhillips Co., Houston, TX (United States); Silpngarmlert, Suntichai [ConocoPhillips Co., Houston, TX (United States); Martin, Kenneth [ConocoPhillips Co., Houston, TX (United States); Smith, Bruce [ConocoPhillips Co., Houston, TX (United States); Klein, Perry [ConocoPhillips Co., Houston, TX (United States)

    2013-06-30

    Work began on the ConocoPhillips Gas Hydrates Production Test (DOE award number DE-NT0006553) on October 1, 2008. This final report summarizes the entire project from January 1, 2011 to June 30, 2013.

  3. ACTUAL PROBLEMS OF MEDICAL GAS OXYGEN PRODUCTION

    OpenAIRE

    Подгорный, И. П.

    2014-01-01

    Medical gas oxygen is one of the most popular medicines. Its production is the major branch of the pharmaceutical industry. Provision of its high quality in the process of obtaining is an actual problem for companies of cryogenic oxygen production. For this purpose a concrete enterprise necessary to implement a quality assurance system in the production of medicinal products (QAS). The main component of the QAS is good manufacturing practice (Good Manufacturing Practice, GMP). It is shown how...

  4. Development of net energy ratio and emission factor for biohydrogen production pathways.

    Science.gov (United States)

    Kabir, Md Ruhul; Kumar, Amit

    2011-10-01

    This study investigates the energy and environmental aspects of producing biohydrogen for bitumen upgrading from a life cycle perspective. Three technologies are studied for biohydrogen production; these include the Battelle Columbus Laboratory (BCL) gasifier, the Gas Technology Institute (GTI) gasifier, and fast pyrolysis. Three different biomass feedstocks are considered including forest residue (FR), whole forest (WF), and agricultural residue (AR). The fast pyrolysis pathway includes two cases: truck transport of bio-oil and pipeline transport of bio-oil. The net energy ratios (NERs) for nine biohydrogen pathways lie in the range of 1.3-9.3. The maximum NER (9.3) is for the FR-based pathway using GTI technology. The GHG emissions lie in the range of 1.20-8.1 kg CO₂ eq/kg H₂. The lowest limit corresponds to the FR-based biohydrogen production pathway using GTI technology. This study also analyzes the intensities for acid rain precursor and ground level ozone precursor. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Timing of the compensation of winter respiratory carbon losses provides explanatory power for net ecosystem productivity of forests

    DEFF Research Database (Denmark)

    Haeni, M.; Zweifel, R.; Eugster, W.

    2017-01-01

    , and Australia, using different NEPc integration methods. We found cDOY to be a particularly powerful predictor for NEPc of temperate evergreen needle-leaf forests (R2 = 0.58) and deciduous broadleaf forests (R2 = 0.68). In general, the latest cDOY correlated with the lowest NEPc. The explanatory power of c......Accurate predictions of net ecosystem productivity (NEPc) of forest ecosystems are essential for climate change decisions and requirements in the context of national forest growth and greenhouse gas inventories. However, drivers and underlying mechanisms determining NEPc (e.g. climate, nutrients......) are not entirely understood yet, particularly when considering the influence of past periods. Here we explored the explanatory power of the compensation day (cDOY) —defined as the day of year when winter net carbon losses are compensated by spring assimilation— for NEPc in 26 forests in Europe, North America...

  6. Timing of the compensation of winter respiratory carbon losses provides explanatory power for net ecosystem productivity of forests

    DEFF Research Database (Denmark)

    Haeni, M.; Zweifel, R.; Eugster, W.

    2017-01-01

    Accurate predictions of net ecosystem productivity (NEPc) of forest ecosystems are essential for climate change decisions and requirements in the context of national forest growth and greenhouse gas inventories. However, drivers and underlying mechanisms determining NEPc (e.g. climate, nutrients......DOY depended on the integration method for NEPc, forest type, and whether the site had a distinct winter net respiratory carbon loss or not. The integration methods starting in autumn led to better predictions of NEPc from cDOY then the classical calendar method starting at January 1. Limited explanatory power...... of cDOY for NEPc was found for warmer sites with no distinct winter respiratory loss period. Our findings highlight the importance of the influence of winter processes and the delayed responses of previous seasons’ climatic conditions on current year's NEPc. Such carry-over effects may contain...

  7. Impacts of tropospheric ozone and climate change on net primary productivity and net carbon exchange of China’s forest ecosystems

    Science.gov (United States)

    Wei Ren; Hanqin Tian; Bo Tao; Art Chappelka; Ge Sun; et al

    2011-01-01

    Aim We investigated how ozone pollution and climate change/variability have interactively affected net primary productivity (NPP) and net carbon exchange (NCE) across China’s forest ecosystem in the past half century. Location Continental China. Methods Using the dynamic land ecosystem model (DLEM) in conjunction with 10-km-resolution gridded historical data sets (...

  8. 17 CFR 229.1204 - (Item 1204) Oil and gas production, production prices and production costs.

    Science.gov (United States)

    2010-04-01

    ... price (including transfers) per unit of oil, gas and other products produced; and (2) The average... conversion to synthetic oil or gas, the product's production, transfer prices, and production costs should be disclosed separately from all other products. Instruction 4 to Item 1204: The transfer price of oil and gas...

  9. Net community production in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.

    flowing Somalia Cur­ rent (SC). After crossing the equator, the SC turns offshore, forming a cold upwelling wedge on its left shoulder. In the central Arabian Sea, the Findlater Jet wind stress forcing and Ekman pumping lead to the injection of nutrient... , is useful as a tracer to evaluate the effect of bubbles on transfer velocity. Keeling et al. [1998] estimated that 0 to 20% error would be introduced because of bubbles in the middle latitudes. Since no such inert gas data are available in the study...

  10. Towards Commercial Gas Production from Hydrate Deposits

    Directory of Open Access Journals (Sweden)

    Richard Dawe

    2011-01-01

    Full Text Available Over the last decade global natural gas consumption has steadily increased since many industrialized countries are substituting natural gas for coal to generate electricity. There is also significant industrialization and economic growth of the heavily populated Asian countries of India and China. The general consensus is that there are vast quantities of natural gas trapped in hydrate deposits in geological systems, and this has resulted in the emerging importance of hydrates as a potential energy resource and an accompanying proliferation of recent studies on the technical and economic feasibility of gas production from hydrates. There are then the associated environmental concerns. This study reviews the state of knowledge with respect to natural gas hydrates and outlines remaining challenges and knowledge gaps.

  11. Seasonal shift in net ecosystem production in a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.S.P.; Nair, S.; Chandramohan, D.

    ) and community respiration (R). Measurements of these variables are a prerequisite to assess the trophic status of aquatic ecosystems. Del Giorgio et al. (1997) suggested that metabolic balance depends on the primary productivity of the system. The rate... of plankton growth efficiency and respiration are important factors that determine the fate of primary production. Recently, hetero- trophy has been reported from euphotic layers of the sub- tropical Northeast Atlantic (Duarte et al. 2001; Hoppe et al. 2002...

  12. Gas Mitigation in Paper Production

    Science.gov (United States)

    Santos, AS; Bittencourt, C.

    2017-07-01

    The Brazilian paper industry has competitive advantages offered by the favorable climate, which favors an increase in the yield of forest restoration, and consequently, in the productive process. On the other hand, following the greenhouse gases (GHG), we can see our constantly changing sun, causing the solar storms, allowing their prevention or mitigating measures. The objective of this work is to contribute to the construction of the understanding necessary for the reduction of GHG emission from a preliminary analysis of the pulp and paper sector. As a secondary objective, the text preliminarily analyzes a company’s behavior against the backdrop of the Paris Accord, which strengthens the global response to the threat of climate change and strengthens the capacity of countries to deal with the impacts of such changes. The identification of best practices in the pulp and paper industry is understood, focusing on environmental sustainability, such as the adoption of reforestation, obtaining significant results. In the case of the paper industry, the management of public forests for sustainable production, within the structure of the Ministry of the Environment, establishes the promotion of public awareness about the importance of conservation, recovery and sustainable management of forest resources.

  13. Annual Net Ecosystem Productivity of Wetlands: A Comparison of Automated and Manual Chamber Methods

    Science.gov (United States)

    Burrows, E. H.; Bubier, J. L.; Mosedale, A.; Crill, P. M.

    2001-05-01

    Net Ecosystem Exchange (NEE) of carbon dioxide (CO2) was measured in a minerotrophic poor fen in southeastern New Hampshire during the 2000 growing season using two types of chamber methods. Instantaneous CO2 flux was measured with transparent lexan and teflon static climate controlled chambers by calculating the change in headspace CO2 concentration in the chamber over time. Once per week the flux was sampled from ten manually operated chambers using a LI-COR 6200 portable photosynthesis system, which included a LI-6250 infrared gas analyzer, connected to the chambers. Ten automated chambers were installed in May of 2000, sampling CO2 flux every three hours over the diurnal cycle using a LI-COR 6262 infrared gas analyzer. The chambers and collars were placed throughout the fen in order to sample the range of plant communities. The manual sampling was done during the middle of the day, but the rate of photosynthesis changes depending on the amount of photosynthetically active radiation (PAR). In order to simulate varying light levels, shrouds blocking different amounts of light were placed over each manual chamber. An opaque shroud was used to measure respiration. NEE ranged from -13.0 to 12.5 μ mol CO2/m2/s in the manual chambers and -16.2 to 11.8 μ mol CO2/m2/s in the automated chambers for the mid-summer growing season. Manual respiration fluxes were measured under higher temperature regimes and the response of respiration to temperature will be factored in when comparing the two chamber techniques. Research during the summer of 2001 will also include diurnal measurements. Growing season net ecosystem productivity (NEP) will be estimated and compared for the two chamber systems. Several models will be used to estimate the flux when the manual chambers were not being sampled. The models will be based on biomass and dominant species in each chamber, and various environmental factors including water table, pH, relative humidity, PAR, air and peat temperature

  14. A life cycle greenhouse gas inventory of a tree production system

    Science.gov (United States)

    Alissa Kendall; E. Gregory McPherson

    2012-01-01

    PurposeThis study provides a detailed, process-based life cycle greenhouse gas (GHG) inventory of an ornamental tree production system for urban forestry. The success of large-scale tree planting initiatives for climate protection depends on projects being net sinks for CO2 over their entire life cycle....

  15. Software for evaluating greenhouse gas emissions and the carbon footprint of dairy production systems

    Science.gov (United States)

    Abstract: Dairy production, along with all other types of animal agriculture, is a recognized source of greenhouse gas (GHG) emissions, but little information exists on the net emissions from our farms. Component models for representing all important sources and sinks of CH4, N2O, and CO2 in dairy p...

  16. Greenhouse gas and carbon profile of the U.S. forest products industry value chain

    Science.gov (United States)

    Linda S. Heath; Van Maltby; Reid Miner; Kenneth E. Skog; James E. Smith; Jay Unwin; Brad Upton

    2010-01-01

    A greenhouse gas and carbon accounting profile was developed for the U.S. forest products industry value chain for 1990 and 2004-2005 by examining net atmospheric fluxes of CO2 and other greenhouse gases (GHGs) using a variety of methods and data sources. Major GHG emission sources include direct and indirect (from purchased electricity...

  17. Life Cycle Assessment of Hydrogen Production via Natural Gas Steam Reforming

    Energy Technology Data Exchange (ETDEWEB)

    Spath, P. L.; Mann, M. K.

    2000-09-28

    A life cycle assessment of hydrogen production via natural gas steam reforming was performed to examine the net emissions of greenhouse gases as well as other major environmental consequences. LCA is a systematic analytical method that helps identify and evaluate the environmental impacts of a specific process or competing processes.

  18. Estimation of livestock appropriation of net primary productivity in Texas Drylands

    Science.gov (United States)

    Robert Washington-Allen; Jody Fitzgerald; Stephanie Grounds; Faisar Jihadi; John Kretzschmar; Kathryn Ramirez; John Mitchell

    2009-01-01

    The ecological state of US Drylands is unknown. This research is developing procedures to determine the impact of the ecological footprint of grazing livestock on the productive capacity of US Drylands. A pilot geodatabase was developed for the state of Texas that includes 2002 data for county boundaries, net primary productivity (NPP) derived from the Moderate...

  19. Increased light-use efficiency sustains net primary productivity of shaded coffee plants in agroforestry system.

    Science.gov (United States)

    Charbonnier, Fabien; Roupsard, Olivier; le Maire, Guerric; Guillemot, Joannès; Casanoves, Fernando; Lacointe, André; Vaast, Philippe; Allinne, Clémentine; Audebert, Louise; Cambou, Aurélie; Clément-Vidal, Anne; Defrenet, Elsa; Duursma, Remko A; Jarri, Laura; Jourdan, Christophe; Khac, Emmanuelle; Leandro, Patricia; Medlyn, Belinda E; Saint-André, Laurent; Thaler, Philippe; Van Den Meersche, Karel; Barquero Aguilar, Alejandra; Lehner, Peter; Dreyer, Erwin

    2017-08-01

    In agroforestry systems, shade trees strongly affect the physiology of the undergrown crop. However, a major paradigm is that the reduction in absorbed photosynthetically active radiation is, to a certain extent, compensated by an increase in light-use efficiency, thereby reducing the difference in net primary productivity between shaded and non-shaded plants. Due to the large spatial heterogeneity in agroforestry systems and the lack of appropriate tools, the combined effects of such variables have seldom been analysed, even though they may help understand physiological processes underlying yield dynamics. In this study, we monitored net primary productivity, during two years, on scales ranging from individual coffee plants to the entire plot. Absorbed radiation was mapped with a 3D model (MAESPA). Light-use efficiency and net assimilation rate were derived for each coffee plant individually. We found that although irradiance was reduced by 60% below crowns of shade trees, coffee light-use efficiency increased by 50%, leaving net primary productivity fairly stable across all shade levels. Variability of aboveground net primary productivity of coffee plants was caused primarily by the age of the plants and by intraspecific competition among them (drivers usually overlooked in the agroforestry literature) rather than by the presence of shade trees. © 2017 John Wiley & Sons Ltd.

  20. Energy self-reliance, net-energy production and GHG emissions in Danish organic cash crop farms

    DEFF Research Database (Denmark)

    Halberg, Niels; Dalgaard, Randi; Olesen, Jørgen E

    2008-01-01

    -energy production were modeled. Growing rapeseed on 10% of the land could produce bio-diesel to replace 50-60% of the tractor diesel used on the farm. Increasing grass-clover area to 20% of the land and using half of this yield for biogas production could change the cash crop farm to a net energy producer......Organic farming (OF) principles include the idea of reducing dependence of fossil fuels, but little has been achieved on this objective so far in Danish OF. Energy use and greenhouse gas (GHG) emissions from an average 39 ha cash crop farm were calculated and alternative crop rotations for bio......, and reduce GHG emissions while reducing the overall output of products only marginally. Increasing grass-clover area would improve the nutrient management on the farm and eliminate dependence on conventional pig slurry if the biogas residues were returned to cash crop fields...

  1. Bio-gas production from alligator weeds

    Science.gov (United States)

    Latif, A.

    1976-01-01

    Laboratory experiments were conducted to study the effect of temperature, sample preparation, reducing agents, light intensity and pH of the media, on bio-gas and methane production from the microbial anaerobic decomposition of alligator weeds (Alternanthera philoxeroides. Efforts were also made for the isolation and characterization of the methanogenic bacteria.

  2. Method of production of ammonia synthesis gas

    Energy Technology Data Exchange (ETDEWEB)

    1943-09-10

    In the catalytic synthesis of complicated hydrocarbons from carbon monoxide and hydrogen at normal or slightly increased pressures by the Fischer--Tropsch process, or carried out at higher pressures in some other proposals, the synthesis gas was incompletely transformed. After the conclusion of the synthesis, the residual gas, upon the separation of the liquid constituents, contained, in addition to the unreacted carbon moxoxide and hydrogen, also considerable amounts of methane, carbon dioxide, and nitrogen from the original synthesis gas. This residual gas had been used as fuel. It was, however, pure and contained no sulfur or other catalyst poisons and burning it was considered uneconomical. It was proposed to make better use of it by using it as fuel. It was, however, pure and contained no sulfur or other catalyst poisons and burning it was considered uneconomical. It was proposed to make better use of it by using it as a raw material for the production of synthesis gas by decomposing the methane present in it with steam according to the equation CH/sub 4/ + H/sub 2/O = CO + 3H/sub 2/. This conversion was to be brought about either by a return to the producers or else in special splitting units. Also, it had been found that the residual gas, possibly even in the presence of oxygen compounds, could be conveniently used for the synthesis of ammonia. Several examples of ammonia synthesis were discussed.

  3. The production of Physalis spp. seedlings grown under different-colored shade nets

    Directory of Open Access Journals (Sweden)

    Daniel Fernandes da Silva

    2016-04-01

    Full Text Available The objective of this study was to evaluate the production of seedlings of Physalis L. species under different-colored shade nets. Four shade nets individually stained white, blue, red and black, all with 50% shading, were used in this study, and an additional  treatment (control was used in which seedlings were grown in full sun. The study examined four species of Physalis, namely, P. peruviana, P. pubescens, P. minima and P. ixocarpa. The experiment followed a randomized block design with three blocks and 25 seeds per plot. The species were sown in styrofoam trays. Germination was monitored daily to calculate the Emergency Velocity Index (EVI and stabilize the overall percentage of emergence. Height, stem diameter, number of leaves, leaf area index and dry mass of seedlings were assessed at 50 days after sowing. The study found that these species react differently to changes in the light spectrum. Seedlings of P. peruviana should be grown under a white or red shade net; of P. pubescens under a white or black shade net; of P. minima under a white, red or black shade net; and of P. ixocarpa under a white shade net. For all species, 50% shade should be used.

  4. [Net energy analysis for annual 200 000 ton cassava ethanol production at Guangxi COFCO].

    Science.gov (United States)

    Yue, Guojun; Sun, Zhenjiang; Shen, Naidong

    2015-02-01

    Guangxi COFCO innovates its annual 200 000 ton cassava ethanol production in recent years. To evaluate the energy input/output of the production process, we used the domestic life cycle model. The calculation results show that the net energy value was 9.56 MJ/L ethanol. Energy input for ethanol production was 51.3% of the total. 61.5% of energy input for ethanol production was used for steam input in ethanol distillation. Energy produced from by-product was 5.03 MJ/L ethanol. Hence, efficient use of raw materials is an important measure to improve the energy efficiency in Guangxi COFCO and energy compensation from byproducts has key impact on the net energy saving.

  5. Net primary production and seasonal CO2 and CH4 fluxes in a Trapa natans L. meadow

    Directory of Open Access Journals (Sweden)

    Marco BARTOLI

    2010-08-01

    Full Text Available The main hypothesis of this work is that Trapa natans L. and similar floating leaved macrophytes are only temporary sinks of atmospheric carbon dioxide and that they favour water hypoxia and large methane efflux from sediment to the atmosphere, due to their shading effect and scarce ability to transfer oxygen to submerged tissues. For this purpose, from April to August 2005, T. natans production, dissolved O2, CO2 and CH4 concentrations in the water column and CO2 and CH4 fluxes across the wateratmosphere interface were measured in an oxbow lake (Lanca di Po, Northern Italy where a monospecific floating mat of water chestnut develops. Net primary production by T. natans was determined via biomass harvesting while gas fluxes were determined via short-term incubations of light and dark floating chambers. From July onwards, when the water surface of the oxbow lake was entirely colonized by the plant, the dense canopy resulted in a physical barrier for light and water reareation. As a consequence of sediment and plant respiration, persistent hypoxia and often anoxia, and CO2 and CH4 supersaturation occurred in the water column. Net primary production of T. natans, calculated at peak biomass, was 13.05 ± 0.32 mol CO2 m-2. The T. natans mat was a net sink for atmospheric CO2 from mid June to mid August, with an uptake peak measured at the beginning of July (229 mmol m-2 d-1; estimated net ecosystem metabolism was ≤10.09 ± 1.90 mol CO2 m-2. Contextually, during the vegetative period of T. natans, the oxbow lake was a net source of methane (9.52 ± 2.10 mol m-2, and the resulting CH4 to CO2 flux ratio across the water-atmosphere interface was ≥0.94. The large methane release was probably due to the persistent hypoxia and anoxia induced by the T. natans meadow, which uncoupled methane production from methane oxidation.

  6. Estimating climate change effects on net primary production of rangelands in the United States

    Science.gov (United States)

    Matthew C. Reeves; Adam L. Moreno; Karen E. Bagne; Steven W. Running

    2014-01-01

    The potential effects of climate change on net primary productivity (NPP) of U.S. rangelands were evaluated using estimated climate regimes from the A1B, A2 and B2 global change scenarios imposed on the biogeochemical cycling model, Biome-BGC from 2001 to 2100. Temperature, precipitation, vapor pressure deficit, day length, solar radiation, CO2 enrichment and nitrogen...

  7. Improved estimates of net primary productivity from MODIS satellite data at regional and local scales

    Science.gov (United States)

    Yude Pan; Richard Birdsey; John Hom; Kevin McCullough; Kenneth Clark

    2006-01-01

    We compared estimates of net primary production (NPP) from the MODIS satellite with estimates from a forest ecosystem process model (PnET-CN) and forest inventory and analysis (FIA) data for forest types of the mid-Atlantic region of the United States. The regional means were similar for the three methods and for the dominant oak? hickory forests in the region. However...

  8. On the spatial heterogeneity of net ecosystem productivity in complex landscapes

    Science.gov (United States)

    Ryan E. Emanuel; Diego A. Riveros-Iregui; Brian L. McGlynn; Howard E. Epstein

    2011-01-01

    Micrometeorological flux towers provide spatially integrated estimates of net ecosystem production (NEP) of carbon over areas ranging from several hectares to several square kilometers, but they do so at the expense of spatially explicit information within the footprint of the tower. This finer-scale information is crucial for understanding how physical and biological...

  9. Disturbance and net ecosystem production across three climatically distinct forest landscapes

    Science.gov (United States)

    John L. Campbell; O.J. Sun; B.E. Law

    2004-01-01

    Biometric techniques were used to measure net ecosystem production (NEP) across three climatically distinct forest chronosequences in Oregon. NEP was highly negative immediately following stand-replacing disturbance in all forests and recovered to positive values by 10, 20, and 30 years of age for the mild mesic Coast Range, mesic West Cascades, and semi-arid East...

  10. Estimating Green Net National Product for Puerto Rico: An Economic Measure of Sustainability (Journal article)

    Science.gov (United States)

    This paper presents the data sources and methodology used to estimate Green Net National Product (GNNP), an economic metric of sustainability, for Puerto Rico. Using the change in GNNP as a one-sided test of weak sustainability (i.e., positive growth in GNNP is not enough to show...

  11. Relationships between net primary productivity and forest stand age in U.S. forests

    Science.gov (United States)

    Liming He; Jing M. Chen; Yude Pan; Richard Birdsey; Jens. Kattge

    2012-01-01

    Net primary productivity (NPP) is a key flux in the terrestrial ecosystem carbon balance, as it summarizes the autotrophic input into the system. Forest NPP varies predictably with stand age, and quantitative information on the NPP-age relationship for different regions and forest types is therefore fundamentally important for forest carbon cycle modeling. We used four...

  12. Impacts of climate change on net primary productivity of grasslands in Inner Mongolia

    NARCIS (Netherlands)

    Li, Q.; Tuo Debao,; Zhang, L.; Wei, X.; Wei, Y.; Yang, N.; Xu, Y.; Anten, N.P.R.; Pan, X.

    2014-01-01

    Net primary productivity (NPP) of grasslands is a key variable for characterising carbon cycles in grassland ecosystems. The prediction of NPP in Inner Mongolia is important for adaptation to future climate change, food security and sustainable use of the grassland resources. The output from two

  13. Effects of precipitation changes on aboveground net primary production and soil respiration in a switchgrass field

    Science.gov (United States)

    This study attempted to test whether switchgrass aboveground net primary production (ANPP) responds to precipitation (PPT) changes in a double asymmetry pattern as framed by Knapp et al. (2016), and whether it is held true for other ecosystem processes such as soil respiration (SR). Data were colle...

  14. UV sensitivity of planktonic net community production in ocean surface waters

    Science.gov (United States)

    Regaudie-de-Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-05-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we test the sensitivity of net community production (NCP) to UVB of planktonic communities in surface waters across contrasting regions of the ocean. We observed here that UVB radiation affects net plankton community production at the ocean surface, imposing a shift in NCP by, on average, 50% relative to the values measured when excluding partly UVB. Our results show that under full solar radiation, the metabolic balance shows the prevalence of net heterotrophic community production. The demonstration of an important effect of UVB radiation on NCP in surface waters presented here is of particular relevance in relation to the increased UVB radiation derived from the erosion of the stratospheric ozone layer. Our results encourage design future research to further our understanding of UVB effects on the metabolic balance of plankton communities.

  15. Fracture technology breaks gas productivity barrier

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, L.

    1975-06-01

    Engineered drilling/completion programs and development of a new fracturing approach have increased gas productivity index from 3-to 8-fold of an unusually hot, tight, deep Smackover pay zone in the S. Sarepta field of Webster and Bossier parishes which is fairly extensive and occurs from 11,110 ft to 11,500 ft. Permeabilities range from 0 to 10 md, porosities from 5 to 12%; bottom-hole temperature is approx. 325/sup 0/F, water saturation is 20%, and estimated gas-in-place ranges from 1,000 to 1,400 Mcf/acre-ft. Condensate varies from 10 to 60 bbl/MMcf. Conventional completions and stimulations in the past have proved disappointing. Pioneering a new approach late in 1973, Sun has increased sustained production from the same Gray Sand. The apparent key that unlocked additional gas reserves and increased productivity was the use of limited entry perforating and carefully controlled stimulation procedures to provide deep penetration fractures. How this was accomplished is described. The basic completion program and tubular specifications are illustrated.

  16. Net energy production associated with pathogen inactivation during mesophilic and thermophilic anaerobic digestion of sewage sludge.

    Science.gov (United States)

    Ziemba, Christopher; Peccia, Jordan

    2011-10-15

    The potential for anaerobic digester energy production must be balanced with the sustainability of reusing the resultant biosolids for land application. Mesophilic, thermophilic, temperature-phased, and high temperature (60 or 70 °C) batch pre-treatment digester configurations have been systematically evaluated for net energy production and pathogen inactivation potential. Energy input requirements and net energy production were modeled for each digester scheme. First-order inactivation rate coefficients for Escherichia coli, Enterococcus faecalis and bacteriophage MS-2 were measured at each digester temperature and full-scale pathogen inactivation performance was estimated for each indicator organism and each digester configuration. Inactivation rates were found to increase dramatically at temperatures above 55 °C. Modeling full-scale performance using retention times based on U.S. EPA time and temperature constraints predicts a 1-2 log inactivation in mesophilic treatment, and a 2-5 log inactivation in 50-55 °C thermophilic and temperature-phased treatments. Incorporating a 60 or 70 °C batch pre-treatment phase resulted in dramatically higher potency, achieving MS-2 inactivation of 14 and 16 logs respectively, and complete inactivation (over 100 log reduction) of E. coli and E. faecalis. For temperatures less than 70 °C, viability staining of thermally-treated E. coli showed significantly reduced inactivation relative to standard culture enumeration. Due to shorter residence times in thermophilic reactors, the net energy production for all digesters was similar (less than 20% difference) with the 60 or 70 °C batch treatment configurations producing the most net energy and the mesophilic treatment producing the least. Incorporating a 60 or 70 °C pre-treatment phase can dramatically increase pathogen inactivation performance without decreasing net energy capture from anaerobic digestion. Energy consumption is not a significant barrier against

  17. Modeling impacts of alternative practices on net global warming potential and greenhouse gas intensity from rice-wheat annual rotation in China.

    Directory of Open Access Journals (Sweden)

    Jinyang Wang

    Full Text Available BACKGROUND: Evaluating the net exchange of greenhouse gas (GHG emissions in conjunction with soil carbon sequestration may give a comprehensive insight on the role of agricultural production in global warming. MATERIALS AND METHODS: Measured data of methane (CH(4 and nitrous oxide (N(2O were utilized to test the applicability of the Denitrification and Decomposition (DNDC model to a winter wheat - single rice rotation system in southern China. Six alternative scenarios were simulated against the baseline scenario to evaluate their long-term (45-year impacts on net global warming potential (GWP and greenhouse gas intensity (GHGI. PRINCIPAL RESULTS: The simulated cumulative CH(4 emissions fell within the statistical deviation ranges of the field data, with the exception of N(2O emissions during rice-growing season and both gases from the control treatment. Sensitivity tests showed that both CH(4 and N(2O emissions were significantly affected by changes in both environmental factors and management practices. Compared with the baseline scenario, the long-term simulation had the following results: (1 high straw return and manure amendment scenarios greatly increased CH(4 emissions, while other scenarios had similar CH(4 emissions, (2 high inorganic N fertilizer increased N(2O emissions while manure amendment and reduced inorganic N fertilizer scenarios decreased N(2O emissions, (3 the mean annual soil organic carbon sequestration rates (SOCSR under manure amendment, high straw return, and no-tillage scenarios averaged 0.20 t C ha(-1 yr(-1, being greater than other scenarios, and (4 the reduced inorganic N fertilizer scenario produced the least N loss from the system, while all the scenarios produced comparable grain yields. CONCLUSIONS: In terms of net GWP and GHGI for the comprehensive assessment of climate change and crop production, reduced inorganic N fertilizer scenario followed by no-tillage scenario would be advocated for this specified

  18. Modeling Impacts of Alternative Practices on Net Global Warming Potential and Greenhouse Gas Intensity from Rice–Wheat Annual Rotation in China

    Science.gov (United States)

    Wang, Jinyang; Zhang, Xiaolin; Liu, Yinglie; Pan, Xiaojian; Liu, Pingli; Chen, Zhaozhi; Huang, Taiqing; Xiong, Zhengqin

    2012-01-01

    Background Evaluating the net exchange of greenhouse gas (GHG) emissions in conjunction with soil carbon sequestration may give a comprehensive insight on the role of agricultural production in global warming. Materials and Methods Measured data of methane (CH4) and nitrous oxide (N2O) were utilized to test the applicability of the Denitrification and Decomposition (DNDC) model to a winter wheat – single rice rotation system in southern China. Six alternative scenarios were simulated against the baseline scenario to evaluate their long-term (45-year) impacts on net global warming potential (GWP) and greenhouse gas intensity (GHGI). Principal Results The simulated cumulative CH4 emissions fell within the statistical deviation ranges of the field data, with the exception of N2O emissions during rice-growing season and both gases from the control treatment. Sensitivity tests showed that both CH4 and N2O emissions were significantly affected by changes in both environmental factors and management practices. Compared with the baseline scenario, the long-term simulation had the following results: (1) high straw return and manure amendment scenarios greatly increased CH4 emissions, while other scenarios had similar CH4 emissions, (2) high inorganic N fertilizer increased N2O emissions while manure amendment and reduced inorganic N fertilizer scenarios decreased N2O emissions, (3) the mean annual soil organic carbon sequestration rates (SOCSR) under manure amendment, high straw return, and no-tillage scenarios averaged 0.20 t C ha−1 yr−1, being greater than other scenarios, and (4) the reduced inorganic N fertilizer scenario produced the least N loss from the system, while all the scenarios produced comparable grain yields. Conclusions In terms of net GWP and GHGI for the comprehensive assessment of climate change and crop production, reduced inorganic N fertilizer scenario followed by no-tillage scenario would be advocated for this specified cropping system. PMID

  19. Perspectives and Problems related to the Shale Gas Production

    Directory of Open Access Journals (Sweden)

    D. P. Gerish

    2014-12-01

    Full Text Available This article describes the main aspects of shale gas production, its origin and properties. The particular issues related to the shale gas production, as well as the public and official attitude to the perspectives of its usage in Russian Federation are analyzed. The general problems of the shale gas exploration and production in the Russian Federation are discussed. The current and prognostic rates of shale gas production in USA are shown.

  20. Bio gas oil production from waste lard.

    Science.gov (United States)

    Hancsók, Jeno; Baladincz, Péter; Kasza, Tamás; Kovács, Sándor; Tóth, Csaba; Varga, Zoltán

    2011-01-01

    Besides the second generations bio fuels, one of the most promising products is the bio gas oil, which is a high iso-paraffin containing fuel, which could be produced by the catalytic hydrogenation of different triglycerides. To broaden the feedstock of the bio gas oil the catalytic hydrogenation of waste lard over sulphided NiMo/Al(2)O(3) catalyst, and as the second step, the isomerization of the produced normal paraffin rich mixture (intermediate product) over Pt/SAPO-11 catalyst was investigated. It was found that both the hydrogenation and the decarboxylation/decarbonylation oxygen removing reactions took place but their ratio depended on the process parameters (T = 280-380°C, P = 20-80 bar, LHSV = 0.75-3.0  h(-1) and H(2)/lard ratio: 600  Nm(3)/m(3)). In case of the isomerization at the favourable process parameters (T = 360-370°C, P = 40-50 bar, LHSV = 1.0  h(-1) and H(2)/hydrocarbon ratio: 400  Nm(3)/m(3)) mainly mono-branching isoparaffins were obtained. The obtained products are excellent Diesel fuel blending components, which are practically free of heteroatoms.

  1. Air pollution causes health effects and net national product of a country decreases: a theoretical framework

    OpenAIRE

    Mohajan, Haradhan

    2011-01-01

    The paper deals with green accounting and accounts the health effects of air pollution. It shows that due to air pollution human capital can not be utilized properly and net national product of a country decreases. The willing to pay system among workers is beneficial to the government, factory owners and workers of a country. The marginal cost-benefit rule for an optimal level of air pollution creates negative health effects. The air pollution cause both direct disutility and indirect welfar...

  2. Synthesis gas production from various biomass feedstocks

    Directory of Open Access Journals (Sweden)

    Juan A. Conesa

    2013-10-01

    Full Text Available The decomposition of five different biomass samples was studied in a horizontal laboratory reactor. The samples consisted of esparto grass, straw, Posidonea Oceanic seaweed, waste from urban and agricultural pruning and waste from forest pruning. Both pyrolysis in inert atmosphere and combustion in the presence of oxygen were studied. Different heating rates were used by varying the input speed. Major gas compounds were analyzed. The experimental results show that the amount of CO formed is lower in less dense species. It is also found that there is an increase of hydrocarbons formed at increasing feeding rates, in particular methane, while there is a decrease in the production of hydrogen.

  3. Regional air quality impacts of increased natural gas production and use in Texas.

    Science.gov (United States)

    Pacsi, Adam P; Alhajeri, Nawaf S; Zavala-Araiza, Daniel; Webster, Mort D; Allen, David T

    2013-04-02

    Natural gas use in electricity generation in Texas was estimated, for gas prices ranging from $1.89 to $7.74 per MMBTU, using an optimal power flow model. Hourly estimates of electricity generation, for individual electricity generation units, from the model were used to estimate spatially resolved hourly emissions from electricity generation. Emissions from natural gas production activities in the Barnett Shale region were also estimated, with emissions scaled up or down to match demand in electricity generation as natural gas prices changed. As natural gas use increased, emissions decreased from electricity generation and increased from natural gas production. Overall, NOx and SO2 emissions decreased, while VOC emissions increased as natural gas use increased. To assess the effects of these changes in emissions on ozone and particulate matter concentrations, spatially and temporally resolved emissions were used in a month-long photochemical modeling episode. Over the month-long photochemical modeling episode, decreases in natural gas prices typical of those experienced from 2006 to 2012 led to net regional decreases in ozone (0.2-0.7 ppb) and fine particulate matter (PM) (0.1-0.7 μg/m(3)). Changes in PM were predominantly due to changes in regional PM sulfate formation. Changes in regional PM and ozone formation are primarily due to decreases in emissions from electricity generation. Increases in emissions from increased natural gas production were offset by decreasing emissions from electricity generation for all the scenarios considered.

  4. The new automotive 42V PowerNet. Preparing for mass production

    Energy Technology Data Exchange (ETDEWEB)

    Graf, A. (ed.)

    2001-07-01

    A number of international auto makers have set themselves the target of getting an automobile with a dual 12V/42V PowerNet into mass production by the year 2005. Reports on practical experience of current projects at leading international auto makers and suppliers allow the reader to get a picture of the status of introduction of the 42V PowerNet and of the problems associated with translating development work into mass production, providing them with an idea of the opportunities for structuring their own company or organizing company activities. The book gives an overview of the problems of introducing the 42V PowerNet into automotive engineering. The basic question here is not 'Why 42V?' but rather 'How can a 42V system be introduced into mass production alongside an existing 12V system?''. It provides information from the standpoint of the engineer and the businessman on: The problems of introduction as seen by the auto maker - Proposed solutions to detailed problems such as short circuits and sparking-System reviews, such as Intelligent Power Management - Suggestions for individual components, such as individual semiconductors - Suggested solutions involving new materials - Solution variants and verification by simulation. (orig.)

  5. Ozone flux over a Norway spruce forest and correlation with net ecosystem production

    Energy Technology Data Exchange (ETDEWEB)

    Zapletal, Milos, E-mail: milos.zapletal@ekotoxa.cz [Ekotoxa s.r.o. - Centre for Environment and Land Assessment, Oticka 37, 746 01 Opava (Czech Republic); Silesian University at Opava, Faculty of Philosophy and Science, Masarykova 37, 746 01 Opava (Czech Republic); Cudlin, Pavel [Institute of Systems Biology and Ecology of the AS CR, v.v.i., Na Sadkach 7, 37005 Ceske Budejovice (Czech Republic); Chroust, Petr [Ekotoxa s.r.o. - Centre for Environment and Land Assessment, Oticka 37, 746 01 Opava (Czech Republic); Urban, Otmar; Pokorny, Radek [Institute of Systems Biology and Ecology of the AS CR, v.v.i., Porici 3b, 60300 Brno (Czech Republic); Edwards-Jonasova, Magda [Institute of Systems Biology and Ecology of the AS CR, v.v.i., Na Sadkach 7, 37005 Ceske Budejovice (Czech Republic); Czerny, Radek; Janous, Dalibor; Taufarova, Klara [Institute of Systems Biology and Ecology of the AS CR, v.v.i., Porici 3b, 60300 Brno (Czech Republic); Vecera, Zbynek; Mikuska, Pavel [Institute of Analytical Chemistry of the AS CR, v.v.i., Veveri 97, 60200 Brno (Czech Republic); Paoletti, Elena [Institute of Plant Protection, National Research Council of Italy, via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2011-05-15

    Daily ozone deposition flux to a Norway spruce forest in Czech Republic was measured using the gradient method in July and August 2008. Results were in good agreement with a deposition flux model. The mean daily stomatal uptake of ozone was around 47% of total deposition. Average deposition velocity was 0.39 cm s{sup -1} and 0.36 cm s{sup -1} by the gradient method and the deposition model, respectively. Measured and modelled non-stomatal uptake was around 0.2 cm s{sup -1}. In addition, net ecosystem production (NEP) was measured by using Eddy Covariance and correlations with O{sub 3} concentrations at 15 m a.g.l., total deposition and stomatal uptake were tested. Total deposition and stomatal uptake of ozone significantly decreased NEP, especially by high intensities of solar radiation. - Highlights: > We estimate ozone deposition flux to a Norway spruce forest using the gradient method and model. > The mean stomatal uptake of ozone is approximately 47% of the total deposition. > We measure net ecosystem production (NEP) using Eddy Covariance. > We test whether elevated total deposition and stomatal uptake of O{sub 3} imply a reduction of NEP. > Deposition and stomatal uptake of O{sub 3} decrease NEP, especially by high intensities of solar radiation. - Net ecosystem production of a Norway spruce forest decreases with increasing deposition and stomatal uptake of ozone.

  6. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species.

    Science.gov (United States)

    Collier, Catherine J; Ow, Yan X; Langlois, Lucas; Uthicke, Sven; Johansson, Charlotte L; O'Brien, Katherine R; Hrebien, Victoria; Adams, Matthew P

    2017-01-01

    Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri). To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt) for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average). This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature). The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C) and H. uninervis (33°C), but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The thermal optimum

  7. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species

    Directory of Open Access Journals (Sweden)

    Catherine J. Collier

    2017-08-01

    Full Text Available Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri. To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average. This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature. The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C and H. uninervis (33°C, but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

  8. Life cycle assessment and sustainable engineering in the context of near net shape grown components: striving towards a sustainable way of future production.

    Science.gov (United States)

    Kämpfer, Christoph; Seiler, Thomas-Benjamin; Beger, Anna-Lena; Jacobs, Georg; Löwer, Manuel; Moser, Franziska; Reimer, Julia; Trautz, Martin; Usadel, Björn; Wormit, Alexandra; Hollert, Henner

    2017-01-01

    Technical product harvesting (TEPHA) is a newly developing interdisciplinary approach in which bio-based production is investigated from a technical and ecological perspective. Society's demand for ecologically produced and sustainably operable goods is a key driver for the substitution of conventional materials like metals or plastics through bio-based alternatives. Technical product harvesting of near net shape grown components describes the use of suitable biomass for the production of technical products through influencing the natural shape of plants during their growth period. The use of natural materials may show positive effects on the amount of non-renewable resource consumption. This also increases the product recyclability at the end of its life cycle. Furthermore, through the near net shape growth of biomass, production steps can be reduced. As a consequence such approaches may save energy and the needed resources like crude oil, coal or gas. The derived near net shape grown components are not only considered beneficial from an environmental point of view. They can also have mechanical advantages through an intrinsic topology optimization in contrast to common natural materials, which are influenced in their shape after harvesting. In order to prove these benefits a comprehensive, interdisciplinary scientific strategy is needed. Here, both mechanical investigations and life cycle assessment as a method of environmental evaluation are used.

  9. The positive net radiative greenhouse gas forcing of increasing methane emissions from a thawing boreal forest-wetland landscape.

    Science.gov (United States)

    Helbig, Manuel; Chasmer, Laura E; Kljun, NatasCha; Quinton, William L; Treat, Claire C; Sonnentag, Oliver

    2017-06-01

    At the southern margin of permafrost in North America, climate change causes widespread permafrost thaw. In boreal lowlands, thawing forested permafrost peat plateaus ('forest') lead to expansion of permafrost-free wetlands ('wetland'). Expanding wetland area with saturated and warmer organic soils is expected to increase landscape methane (CH4 ) emissions. Here, we quantify the thaw-induced increase in CH4 emissions for a boreal forest-wetland landscape in the southern Taiga Plains, Canada, and evaluate its impact on net radiative forcing relative to potential long-term net carbon dioxide (CO2 ) exchange. Using nested wetland and landscape eddy covariance net CH4 flux measurements in combination with flux footprint modeling, we find that landscape CH4 emissions increase with increasing wetland-to-forest ratio. Landscape CH4 emissions are most sensitive to this ratio during peak emission periods, when wetland soils are up to 10 °C warmer than forest soils. The cumulative growing season (May-October) wetland CH4 emission of ~13 g CH4  m-2 is the dominating contribution to the landscape CH4 emission of ~7 g CH4  m-2 . In contrast, forest contributions to landscape CH4 emissions appear to be negligible. The rapid wetland expansion of 0.26 ± 0.05% yr-1 in this region causes an estimated growing season increase of 0.034 ± 0.007 g CH4  m-2  yr-1 in landscape CH4 emissions. A long-term net CO2 uptake of >200 g CO2  m-2  yr-1 is required to offset the positive radiative forcing of increasing CH4 emissions until the end of the 21st century as indicated by an atmospheric CH4 and CO2 concentration model. However, long-term apparent carbon accumulation rates in similar boreal forest-wetland landscapes and eddy covariance landscape net CO2 flux measurements suggest a long-term net CO2 uptake between 49 and 157 g CO2  m-2  yr-1 . Thus, thaw-induced CH4 emission increases likely exert a positive net radiative greenhouse gas forcing through the 21st century.

  10. Impact of the diet on net endogenous acid production and acid-base balance.

    Science.gov (United States)

    Poupin, Nathalie; Calvez, Juliane; Lassale, Camille; Chesneau, Caroline; Tomé, Daniel

    2012-06-01

    Net acid production, which is composed of volatile acids (15,000 mEq/day) and metabolic acids (70-100 mEq/day) is relatively small compared to whole-body H⁺ turnover (150,000 mEq/day). Metabolic acids are ingested from the diet or produced as intermediary or end products of endogenous metabolism. The three commonly reported sources of net acid production are the metabolism of sulphur amino acids, the metabolism or ingestion of organic acids, and the metabolism of phosphate esters or dietary phosphoproteins. Net base production occurs mainly as a result of absorption of organic anions from the diet. To maintain acid-base balance, ingested and endogenously produced acids are neutralized within the body by buffer systems or eliminated from the body through the respiratory (excretion of volatile acid in the form of CO₂) and urinary (excretion of fixed acids and remaining H⁺) pathways. Because of the many reactions involved in the acid-base balance, the direct determination of acid production is complex and is usually estimated through direct or indirect measurements of acid excretion. However, indirect approaches, which assess the acid-forming potential of the ingested diet based on its composition, do not take all the acid-producing reactions into account. Direct measurements therefore seem more reliable. Nevertheless, acid excretion does not truly provide information on the way acidity is dealt with in the plasma and this measurement should be interpreted with caution when assessing acid-base imbalance. Copyright © 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  11. A global meta-analysis on the impact of management practices on net global warming potential and greenhouse gas intensity from cropland soils

    Science.gov (United States)

    Agricultural practices contribute significant amount of greenhouse gas (GHG) emissions, but little is known about their effects on net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of carbon dioxide emissions per unit area or crop yield. Se...

  12. The CAFE model: A net production model for global ocean phytoplankton

    Science.gov (United States)

    Silsbe, Greg M.; Behrenfeld, Michael J.; Halsey, Kimberly H.; Milligan, Allen J.; Westberry, Toby K.

    2016-12-01

    The Carbon, Absorption, and Fluorescence Euphotic-resolving (CAFE) net primary production model is an adaptable framework for advancing global ocean productivity assessments by exploiting state-of-the-art satellite ocean color analyses and addressing key physiological and ecological attributes of phytoplankton. Here we present the first implementation of the CAFE model that incorporates inherent optical properties derived from ocean color measurements into a mechanistic and accurate model of phytoplankton growth rates (μ) and net phytoplankton production (NPP). The CAFE model calculates NPP as the product of energy absorption (QPAR), and the efficiency (ϕμ) by which absorbed energy is converted into carbon biomass (CPhyto), while μ is calculated as NPP normalized to CPhyto. The CAFE model performance is evaluated alongside 21 other NPP models against a spatially robust and globally representative set of direct NPP measurements. This analysis demonstrates that the CAFE model explains the greatest amount of variance and has the lowest model bias relative to other NPP models analyzed with this data set. Global oceanic NPP from the CAFE model (52 Pg C m-2 yr-1) and mean division rates (0.34 day-1) are derived from climatological satellite data (2002-2014). This manuscript discusses and validates individual CAFE model parameters (e.g., QPAR and ϕμ), provides detailed sensitivity analyses, and compares the CAFE model results and parameterization to other widely cited models.

  13. Assessing the impact of urbanization on regional net primary productivity in Jiangyin County, China.

    Science.gov (United States)

    Xu, C; Liu, M; An, S; Chen, J M; Yan, P

    2007-11-01

    Urbanization is one of the most important aspects of global change. The process of urbanization has a significant impact on the terrestrial ecosystem carbon cycle. The Yangtze Delta region has one of the highest rates of urbanization in China. In this study, carried out in Jiangyin County as a representative region within the Yangtze Delta, land use and land cover changes were estimated using Landsat TM and ETM+ imagery. With these satellite data and the BEPS process model (Boreal Ecosystem Productivity Simulator), the impacts of urbanization on regional net primary productivity (NPP) and annual net primary production were assessed for 1991 and 2002. Landsat-based land cover maps in 1991 and 2002 showed that urban development encroached large areas of cropland and forest. Expansion of residential areas and reduction of vegetated areas were the major forms of land transformation in Jiangyin County during this period. Mean NPP of the total area decreased from 818 to 699 gCm(-2)yr(-1) during the period of 1991 to 2002. NPP of cropland was only reduced by 2.7% while forest NPP was reduced by 9.3%. Regional annual primary production decreased from 808 GgC in 1991 to 691 GgC in 2002, a reduction of 14.5%. Land cover changes reduced regional NPP directly, and the increasing intensity and frequency of human-induced disturbance in the urbanized areas could be the main reason for the decrease in forest NPP.

  14. IMPACT OF UNCONVENTIONAL GAS PRODUCTION ON LNG SUPPLY AND DEMAND

    Directory of Open Access Journals (Sweden)

    Daria Karasalihović Sedlar

    2010-12-01

    Full Text Available Production of unconventional gas plays a double role in the case of liquefied natural gas (LNG industry. Technological development of gas production from unconventional resources could result in significant decrease of LNG import demand but at the same time unconventional resources also represent a potential for new sources of LNG supply. In past few years unconventional gas production in North America has increased constantly what has contributed to natural gas prices decrease and LNG imports reduction. The rise of unconventional gas production along with global recession significantly influenced LNG demand decrease in the USA. Concerning unconventional gas production rapid development, potential decrease of LNG demand in rest of the world is expected (the paper is published in Croatian.

  15. Water use for Shale-gas production in Texas, U.S.

    Science.gov (United States)

    Nicot, Jean-Philippe; Scanlon, Bridget R

    2012-03-20

    Shale-gas production using hydraulic fracturing of mostly horizontal wells has led to considerable controversy over water-resource and environmental impacts. The study objective was to quantify net water use for shale-gas production using data from Texas, which is the dominant producer of shale gas in the U.S. with a focus on three major plays: the Barnett Shale (~15,000 wells, mid-2011), Texas-Haynesville Shale (390 wells), and Eagle Ford Shale (1040 wells). Past water use was estimated from well-completion data, and future water use was extrapolated from past water use constrained by shale-gas resources. Cumulative water use in the Barnett totaled 145 Mm(3) (2000-mid-2011). Annual water use represents ~9% of water use in Dallas (population 1.3 million). Water use in younger (2008-mid-2011) plays, although less (6.5 Mm(3) Texas-Haynesville, 18 Mm(3) Eagle Ford), is increasing rapidly. Water use for shale gas is water withdrawals; however, local impacts vary with water availability and competing demands. Projections of cumulative net water use during the next 50 years in all shale plays total ~4350 Mm(3), peaking at 145 Mm(3) in the mid-2020s and decreasing to 23 Mm(3) in 2060. Current freshwater use may shift to brackish water to reduce competition with other users.

  16. DairyGHG: a tool for evaluating the greenhouse gas emissions and carbon footprint of dairy production systems

    Science.gov (United States)

    Greenhouse gas (GHG) emissions and their potential impact on the environment have become important national and international concerns. Dairy production, along with all other animal agriculture, is a recognized source of GHG emissions, but little information exists on the net emissions from our farm...

  17. MISR Level 3 Component Global Land product in netCDF format covering a day V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 Component Global Land Product in netCDF contains a daily statistical summary of directional hemispherical reflectance (DHR), photosynthetically...

  18. MISR Level 3 Component Global Land product in netCDF format covering a year V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 Yearly Component Global Land Product in netCDF contains a yearly statistical summary of directional hemispherical reflectance (DHR),...

  19. MISR Level 3 Component Global Land product in netCDF format covering a month V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 Monthly Component Global Land Product in netCDF contains a monthly statistical summary of directional hemispherical reflectance (DHR),...

  20. MISR Level 3 FIRSTLOOK Global Albedo product in netCDF format covering a day V002

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 FIRSTLOOK Component Global Albedo Product in netCDF covering a day contains a statistical summary of column albedo 555 nanometer optical depth, and...

  1. MISR Level 3 FIRSTLOOK Global Albedo product in netCDF format covering a month V002

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 FIRSTLOOK Component Global Albedo Product in netCDF format covering a month contains a statistical summary of column albedo 555 nanometer optical...

  2. MISR Level 3 FIRSTLOOK Global Aerosol product in netCDF format covering a day V002

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 FIRSTLOOK Global Aerosol Product in netCDF format covering a day contains a statistical summary of column aerosol 555 nanometer optical depth, and a...

  3. Temperature response of denitrification rate and greenhouse gas production in agricultural river marginal wetland soils.

    Science.gov (United States)

    Bonnett, S A F; Blackwell, M S A; Leah, R; Cook, V; O'Connor, M; Maltby, E

    2013-05-01

    Soils are predicted to exhibit significant feedback to global warming via the temperature response of greenhouse gas (GHG) production. However, the temperature response of hydromorphic wetland soils is complicated by confounding factors such as oxygen (O2 ), nitrate (NO3-) and soil carbon (C). We examined the effect of a temperature gradient (2-25 °C) on denitrification rates and net nitrous oxide (N2 O), methane (CH4 ) production and heterotrophic respiration in mineral (Eutric cambisol and Fluvisol) and organic (Histosol) soil types in a river marginal landscape of the Tamar catchment, Devon, UK, under non-flooded and flooded with enriched NO3- conditions. It was hypothesized that the temperature response is dependent on interactions with NO3--enriched flooding, and the physicochemical conditions of these soil types. Denitrification rate (mean, 746 ± 97.3 μg m(-2)  h(-1) ), net N2 O production (mean, 180 ± 26.6 μg m(-2)  h(-1) ) and net CH4 production (mean, 1065 ± 183 μg m(-2)  h(-1) ) were highest in the organic Histosol, with higher organic matter, ammonium and moisture, and lower NO3- concentrations. Heterotrophic respiration (mean, 127 ± 4.6 mg m(-2)  h(-1) ) was not significantly different between soil types and dominated total GHG (CO2 eq) production in all soil types. Generally, the temperature responses of denitrification rate and net N2 O production were exponential, whilst net CH4 production was unresponsive, possibly due to substrate limitation, and heterotrophic respiration was exponential but limited in summer at higher temperatures. Flooding with NO3- increased denitrification rate, net N2 O production and heterotrophic respiration, but a reduction in net CH4 production suggests inhibition of methanogenesis by NO3- or N2 O produced from denitrification. Implications for management and policy are that warming and flood events may promote microbial interactions in soil between distinct microbial communities and increase

  4. Worldwide estimates and bibliography of net primary productivity derived from pre-1982 publications

    Energy Technology Data Exchange (ETDEWEB)

    Esser, G. [Justus-Liebig-Univ., Giessen (Germany). Inst. for Plant Ecology; Lieth, H.F.H. [Univ. of Osnabrueck (Germany). Systems Research Group; Scurlock, J.M.O.; Olson, R.J. [Oak Ridge National Lab., TN (United States)

    1997-10-01

    An extensive compilation of more than 700 field estimates of net primary productivity of natural and agricultural ecosystems worldwide was synthesized in Germany in the 1970s and early 1980s. Although the Osnabrueck data set has not been updated since the 1980s, it represents a wealth of information for use in model development and validation. This report documents the development of this data set, its contents, and its recent availability on the Internet from the Oak Ridge National Laboratory Distributed Active Archive Center for Biogeochemical Dynamics. Caution is advised in using these data, which necessarily include assumptions and conversions that may not be universally applicable to all sites.

  5. Quantifying and mapping the human appropriation of net primary production in earth's terrestrial ecosystems.

    Science.gov (United States)

    Haberl, Helmut; Erb, K Heinz; Krausmann, Fridolin; Gaube, Veronika; Bondeau, Alberte; Plutzar, Christoph; Gingrich, Simone; Lucht, Wolfgang; Fischer-Kowalski, Marina

    2007-07-31

    Human appropriation of net primary production (HANPP), the aggregate impact of land use on biomass available each year in ecosystems, is a prominent measure of the human domination of the biosphere. We present a comprehensive assessment of global HANPP based on vegetation modeling, agricultural and forestry statistics, and geographical information systems data on land use, land cover, and soil degradation that localizes human impact on ecosystems. We found an aggregate global HANPP value of 15.6 Pg C/yr or 23.8% of potential net primary productivity, of which 53% was contributed by harvest, 40% by land-use-induced productivity changes, and 7% by human-induced fires. This is a remarkable impact on the biosphere caused by just one species. We present maps quantifying human-induced changes in trophic energy flows in ecosystems that illustrate spatial patterns in the human domination of ecosystems, thus emphasizing land use as a pervasive factor of global importance. Land use transforms earth's terrestrial surface, resulting in changes in biogeochemical cycles and in the ability of ecosystems to deliver services critical to human well being. The results suggest that large-scale schemes to substitute biomass for fossil fuels should be viewed cautiously because massive additional pressures on ecosystems might result from increased biomass harvest.

  6. Decreasing Net Primary Productivity in Response to Urbanization in Liaoning Province, China

    Directory of Open Access Journals (Sweden)

    Tan Chen

    2017-01-01

    Full Text Available Regional ecosystems have been greatly affected by the rapid expansion of urban areas. In order to explore the impact of land use change on net primary productivity (NPP in rapidly developing cities during the current urbanization process, we quantified land use change in Liaoning province between 2000 and 2010 using net primary productivity as an indicator of ecosystem productivity and health. The Carnegie–Ames–Stanford Approach model was used to estimate NPP by region and land use. We used a unit circle-based evaluation model to quantify local urbanization effects on NPP around eight representative cities. The dominant land use types were farmland, woodland and urban, with urban rapidly replacing farmland. Mean annual NPP and total NPP decreased faster from 2005 to 2010 than from 2000 to 2005, reflecting increasing urbanization rates. The eastern, primarily woodland part of Liaoning province had the greatest reduction in NPP, while the western part, which was primarily farmland and grassland, had the lowest reduction.

  7. Net primary productivity of forest stands in New Hampshire estimated from Landsat and MODIS satellite data

    Directory of Open Access Journals (Sweden)

    Genovese Vanessa

    2007-10-01

    Full Text Available Abstract Background A simulation model that relies on satellite observations of vegetation cover from the Landsat 7 sensor and from the Moderate Resolution Imaging Spectroradiometer (MODIS was used to estimate net primary productivity (NPP of forest stands at the Bartlett Experiment Forest (BEF in the White Mountains of New Hampshire. Results Net primary production (NPP predicted from the NASA-CASA model using 30-meter resolution Landsat inputs showed variations related to both vegetation cover type and elevational effects on mean air temperatures. Overall, the highest predicted NPP from the NASA-CASA model was for deciduous forest cover at low to mid-elevation locations over the landscape. Comparison of the model-predicted annual NPP to the plot-estimated values showed a significant correlation of R2 = 0.5. Stepwise addition of 30-meter resolution elevation data values explained no more than 20% of the residual variation in measured NPP patterns at BEF. Both the Landsat 7 and the 250-meter resolution MODIS derived mean annual NPP predictions for the BEF plot locations were within ± 2.5% of the mean of plot estimates for annual NPP. Conclusion Although MODIS imagery cannot capture the spatial details of NPP across the network of closely spaced plot locations as well as Landsat, the MODIS satellite data as inputs to the NASA-CASA model does accurately predict the average annual productivity of a site like the BEF.

  8. Production optimization of remotely operated gas wells

    Energy Technology Data Exchange (ETDEWEB)

    Juell, Aleksander

    2012-07-01

    From the introduction: The Remote Operations in Oklahoma Intended for Education (ROOKIE) project is a remote field laboratory constructed as a part of this research project. ROOKIE was initiated to provide data in research on production optimization of low productivity gas wells. In addition to this, ROOKIE is used as a teaching tool. Much of the remote operations technology used in the ROOKIE project has been used by the industry for several decades. The first use of remote data acquisition in Oklahoma was in 1989, as described by Luppens [7]. Even though this, for the most part, is old technology, the ROOKIE project is the first remote operations project set up with research and teaching as the main focus. This chapter will discuss the process of establishing the remote field laboratory and the data storage facilities. Results from the project will also be discussed. All testing, instrumentation installation, and modifications to the wells discussed in this chapter was performed by the author. The communication system between the well and NTNU, and the storage database was installed and configured by the author.(Author)

  9. Disturbance, complexity, and succession of net ecosystem production in North America’s temperate deciduous forests

    Energy Technology Data Exchange (ETDEWEB)

    Gough, Christopher; Curtis, Peter; Hardiman, Brady; Scheuermann, Cynthia; Bond-Lamberty, Benjamin

    2016-06-29

    Century-old forests in the U.S. upper Midwest and Northeast power much of North Amer- ica’s terrestrial carbon (C) sink, but these forests’ production and C sequestration capacity are expected to soon decline as fast-growing early successional species die and are replaced by slower growing late successional species. But will this really happen? Here we marshal empirical data and ecological theory to argue that substantial declines in net ecosystem production (NEP) owing to reduced forest growth, or net primary production (NPP), are not imminent in regrown temperate deciduous forests over the next several decades. Forest age and production data for temperate deciduous forests, synthesized from published literature, suggest slight declines in NEP and increasing or stable NPP during middle successional stages. We revisit long-held hypotheses by EP Odum and others that suggest low-severity, high-frequency disturbances occurring in the region’s aging forests will, against intuition, maintain NEP at higher-than- expected rates by increasing ecosystem complexity, sustaining or enhancing NPP to a level that largely o sets rising C losses as heterotrophic respiration increases. This theoretical model is also supported by biological evidence and observations from the Forest Accelerated Succession Experiment in Michigan, USA. Ecosystems that experience high-severity disturbances that simplify ecosystem complexity can exhibit substantial declines in production during middle stages of succession. However, observations from these ecosystems have exerted a disproportionate in uence on assumptions regarding the trajectory and magnitude of age-related declines in forest production. We conclude that there is a wide ecological space for forests to maintain NPP and, in doing so, lessens the declines in NEP, with signi cant implications for the future of the North American carbon sink. Our intellectual frameworks for understanding forest C cycle dynamics and resilience need to

  10. Net farm income and land use under a U.S. greenhouse gas cap and trade

    Science.gov (United States)

    Justin S. Baker; Bruce A. McCarl; Brian C. Murray; Steven K. Rose; Ralph J. Alig; Darius Adams; Greg Latta; Robert Beach; Adam. Daigneault

    2010-01-01

    During recent years, the U.S. agricultural sector has experienced high prices for energy related inputs and commodities, and a rapidly developing bioenergy market. Greenhouse gas (GHG) emissions mitigation would further alter agricultural markets and increase land competition in forestry and agriculture by shifting input costs, creating an agricultural GHG abatement...

  11. Estimating crop net primary production using inventory data and MODIS-derived parameters

    Energy Technology Data Exchange (ETDEWEB)

    Bandaru, Varaprasad; West, Tristram O.; Ricciuto, Daniel M.; Izaurralde, Roberto C.

    2013-06-03

    National estimates of spatially-resolved cropland net primary production (NPP) are needed for diagnostic and prognostic modeling of carbon sources, sinks, and net carbon flux. Cropland NPP estimates that correspond with existing cropland cover maps are needed to drive biogeochemical models at the local scale and over national and continental extents. Existing satellite-based NPP products tend to underestimate NPP on croplands. A new Agricultural Inventory-based Light Use Efficiency (AgI-LUE) framework was developed to estimate individual crop biophysical parameters for use in estimating crop-specific NPP. The method is documented here and evaluated for corn and soybean crops in Iowa and Illinois in years 2006 and 2007. The method includes a crop-specific enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS), shortwave radiation data estimated using Mountain Climate Simulator (MTCLIM) algorithm and crop-specific LUE per county. The combined aforementioned variables were used to generate spatially-resolved, crop-specific NPP that correspond to the Cropland Data Layer (CDL) land cover product. The modeling framework represented well the gradient of NPP across Iowa and Illinois, and also well represented the difference in NPP between years 2006 and 2007. Average corn and soybean NPP from AgI-LUE was 980 g C m-2 yr-1 and 420 g C m-2 yr-1, respectively. This was 2.4 and 1.1 times higher, respectively, for corn and soybean compared to the MOD17A3 NPP product. Estimated gross primary productivity (GPP) derived from AgI-LUE were in close agreement with eddy flux tower estimates. The combination of new inputs and improved datasets enabled the development of spatially explicit and reliable NPP estimates for individual crops over large regional extents.

  12. Targeting International Food Aid Programmes: The Case of Productive Safety Net Programme in Tigray, Ethiopia

    Directory of Open Access Journals (Sweden)

    Hossein Azadi

    2017-09-01

    Full Text Available Ethiopia has experienced more than five major droughts in the past three decades, leading to high dependency on international food aids. Nevertheless, studies indicate that asset depletion has not been prevented; neither did food insecurity diminish. Since 2004/5, the Productive Safety Net Programme (PSNP has been implemented to improve food security in Tigray, Northern Ethiopia. Critics point out that the implementation of food aid programmes can have negative impacts as well as positive outcomes for local communities. Accordingly, this survey study aimed to analyse the distribution and allocation of food aids in the Productive Safety Net Programme (PSNP in Tigray. Results of 479 interviews revealed that targeting different households in the PSNP has been considerably linked to socio-demographic attributes among which age and size of family were decisive factors to receive food aids. Furthermore, older households with smaller family size received more direct support. Inequality between genders was another major finding of this study. When combined with the marital status, there was also a big difference in the percentage of married or unmarried women receiving food aids. These findings could provide fundamental information for policy intervention to correct food security programmes at household level and reduce hunger. Given that, socio-demographic factors can help to identify particular and usually different requirements, vulnerabilities and coping strategies of the members of the food aid programme, so that they can be much more addressed when an emergency happens.

  13. GASCAP: Wellhead Gas Productive Capacity Model documentation, June 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    The Wellhead Gas Productive Capacity Model (GASCAP) has been developed by EIA to provide a historical analysis of the monthly productive capacity of natural gas at the wellhead and a projection of monthly capacity for 2 years into the future. The impact of drilling, oil and gas price assumptions, and demand on gas productive capacity are examined. Both gas-well gas and oil-well gas are included. Oil-well gas productive capacity is estimated separately and then combined with the gas-well gas productive capacity. This documentation report provides a general overview of the GASCAP Model, describes the underlying data base, provides technical descriptions of the component models, diagrams the system and subsystem flow, describes the equations, and provides definitions and sources of all variables used in the system. This documentation report is provided to enable users of EIA projections generated by GASCAP to understand the underlying procedures used and to replicate the models and solutions. This report should be of particular interest to those in the Congress, Federal and State agencies, industry, and the academic community, who are concerned with the future availability of natural gas.

  14. Energy balance of maize production in Brazil: the energetic constraints of a net positive outcome

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Luis Henrique de Barros; Alves, Bruno Jose Rodrigues; Urquiaga, Segundo

    2008-07-01

    Among the factors used to analyze and to establish the sustainability of a whole agricultural production system, the energy balance is one of the most powerful and robust. The maize production in Brazil is surely the reflex of an energy intensive system that demands many field operations and heavy fertilizer applications, notably nitrogen in urea form. This work presents an energy balance of this major crop adjusted to the Brazilian conditions of cultivation. The input components were grouped based on their energy contents, and the possible improvements in the agricultural practices that could improve energy balance and net energy withdrawn from the farming were considered. The replacement of N synthetic fertilizer by biological nitrogen fixation, whether the process is directly carried out by endophytic diazotroph bacteria or by means of a N{sub 2}- fixing legume culture planted before the main crop as a green-manure is also discussed. (author)

  15. Lattice Model for Production of Gas

    KAUST Repository

    Marder, M.

    2017-12-01

    We define a lattice model for rock, absorbers, and gas that makes it possible to examine the flow of gas to a complicated absorbing boundary over long periods of time. The motivation is to deduce the geometry of the boundary from the time history of gas absorption. We find a solution to this model using Green\\'s function techniques, and apply the solution to three absorbing networks of increasing complexity.

  16. Genetic parameters of estimated net energy efficiencies for milk production, maintenance, and body weight change in dairy cows.

    Science.gov (United States)

    Buttazzoni, L; Mao, I L

    1989-03-01

    Net efficiencies of converting intake energy into energy for maintenance, milk production, and body weight change in a lactation were estimated for each of 79 Holstein cows by a two-stage multiple regression model. Cows were from 16 paternal half-sib families, which each had members in at least two of the six herds. Each cow was recorded for milk yield, net energy intake, and three efficiency traits. These were analyzed in a multitrait model containing the same 14 fixed subclasses of herd by season by parity and a random factor of sires for each of the five traits. Restricted maximum likelihood estimates of sire and residual (co)variance components were obtained by an expectation maximization algorithm with canonical transformations. Between milk yield and net energy intake, net energy efficiencies for milk yield, maintenance, and body weight change, the estimated phenotypic correlations were .36, -.02, .08, and -.06, while the genetic correlations were .92, .56, .02, and -.32, respectively. Both genetic and phenotypic correlations were zero between net energy efficiency of maintenance and that of milk yield and .17 between net energy efficiency of body weight change and that of milk yield. The estimated genetic correlation between net efficiency for lactation and milk yield is approximately 60% of that between gross efficiency and milk yield. With a heritability of .32 equivalent.49, net energy efficiency for milk yield may be worth consideration for genetic selection in certain dairy cattle populations.

  17. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity.

    Science.gov (United States)

    Stuart-Haëntjens, Ellen J; Curtis, Peter S; Fahey, Robert T; Vogel, Christoph S; Gough, Christopher M

    2015-09-01

    The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C storage. Disturbances to forests occur along a continuum of severity, from low-intensity disturbance causing the mortality or defoliation of only a subset of trees to severe stand- replacing disturbance that kills all trees; yet considerable uncertainty remains in how forest production changes across gradients of disturbance intensity. We used a gradient of tree mortality in an upper Great Lakes forest ecosystem to: (1) quantify how aboveground wood net primary production (ANPP,) responds to a range of disturbance severities; and (2) identify mechanisms supporting ANPPw resistance or resilience following moderate disturbance. We found that ANPPw declined nonlinearly with rising disturbance severity, remaining stable until >60% of the total tree basal area senesced. As upper canopy openness increased from disturbance, greater light availability to the subcanopy enhanced the leaf-level photosynthesis and growth of this formerly light-limited canopy stratum, compensating for upper canopy production losses and a reduction in total leaf area index (LAI). As a result, whole-ecosystem production efficiency (ANPPw/LAI) increased with rising disturbance severity, except in plots beyond the disturbance threshold. These findings provide a mechanistic explanation for a nonlinear relationship between ANPPw, and disturbance severity, in which the physiological and growth enhancement of undisturbed vegetation is proportional to the level of disturbance until a threshold is exceeded. Our results have important ecological and management implications, demonstrating that in some ecosystems moderate levels of disturbance minimally alter forest production.

  18. A generic multistage compartmental model for interpreting gas production profiles

    NARCIS (Netherlands)

    Lopez, S.; Dijkstra, J.; Dhanoa, M.S.; Bannink, A.; Kebreab, E.; France, J.

    2010-01-01

    The gas production technique has become a key tool in feed evaluation and rumen fermentation studies. The value of the technique relies on modelling experimental data to obtain estimates of rumen degradation parameters. One of the first models used to describe gas production profiles was the simple

  19. Relationship between gas production and starch degradation in feed samples

    NARCIS (Netherlands)

    Chai, W.Z.; Gelder, van A.H.; Cone, J.W.

    2004-01-01

    An investigation was completed of the possibilities to estimate starch fermentation in rumen fluid using the gas production technique by incubating the total sample. Gas production from six starchy feed ingredients and eight maize silage samples were recorded and related to starch degradation

  20. Carbon dioxide emission in hydrogen production technology from coke oven gas with life cycle approach

    Directory of Open Access Journals (Sweden)

    Burmistrz Piotr

    2016-01-01

    Full Text Available The analysis of Carbon Footprint (CF for technology of hydrogen production from cleaned coke oven gas was performed. On the basis of real data and simulation calculations of the production process of hydrogen from coke gas, emission indicators of carbon dioxide (CF were calculated. These indicators are associated with net production of electricity and thermal energy and direct emission of carbon dioxide throughout a whole product life cycle. Product life cycle includes: coal extraction and its transportation to a coking plant, the process of coking coal, purification and reforming of coke oven gas, carbon capture and storage. The values were related to 1 Mg of coking blend and to 1 Mg of the hydrogen produced. The calculation is based on the configuration of hydrogen production from coke oven gas for coking technology available on a commercial scale that uses a technology of coke dry quenching (CDQ. The calculations were made using ChemCAD v.6.0.2 simulator for a steady state of technological process. The analysis of carbon footprint was conducted in accordance with the Life Cycle Assessment (LCA.

  1. Inventory-based estimation of aboveground net primary production in Japan's forests from 1980 to 2005

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2011-08-01

    Full Text Available Recent studies based on remote sensing and carbon process models have revealed that terrestrial net primary production (NPP in the middle and high latitudes of the Northern Hemisphere has increased significantly; this is crucial for explaining the increased terrestrial carbon sink in the past several decades. Regional NPP estimation based on significant field data, however, has been rare. In this study, we estimated the long-term changes in aboveground NPP (ANPP for Japan's forests from 1980 to 2005 using forest inventory data, direct field measurements, and an allometric method. The overall ANPP for all forest types averaged 10.5 Mg ha−1 yr−1, with a range of 9.6 to 11.5 Mg ha−1 yr−1, and ANPP for the whole country totaled 249.1 Tg yr−1 (range: 230.0 to 271.4 Tg yr−1 during the study period. Over the 25 years, the net effect of increased ANPP in needle-leaf forests and decreased ANPP in broadleaf forests has led to an increase of 1.9 Mg ha−1 yr−1 (i.e., 0.79 % yr−1. This increase may be mainly due to the establishment of plantations and the rapid early growth of these planted forests.

  2. Assessment of net community production and calcification of a coral reef using a boundary layer approach

    Science.gov (United States)

    Takeshita, Yuichiro; McGillis, Wade; Briggs, Ellen M.; Carter, Amanda L.; Donham, Emily M.; Martz, Todd R.; Price, Nichole N.; Smith, Jennifer E.

    2016-08-01

    Coral reefs are threatened worldwide, and there is a need to develop new approaches to monitor reef health under natural conditions. Because simultaneous measurements of net community production (NCP) and net community calcification (NCC) are used as important indicators of reef health, tools are needed to assess them in situ. Here we present the Benthic Ecosystem and Acidification Measurement System (BEAMS) to provide the first fully autonomous approach capable of sustained, simultaneous measurements of reef NCP and NCC under undisturbed, natural conditions on time scales ranging from tens of minutes to weeks. BEAMS combines the chemical and velocity gradient in the benthic boundary layer to quantify flux from the benthos for a variety of parameters to measure NCP and NCC. Here BEAMS was used to measure these rates from two different sites with different benthic communities on the western reef terrace at Palmyra Atoll for 2 weeks in September 2014. Measurements were made every ˜15 min. The trends in metabolic rates were consistent with the benthic communities between the two sites with one dominated by fleshy organisms and the other dominated by calcifiers (degraded and healthy reefs, respectively). This demonstrates the potential utility of BEAMS as a reef health monitoring tool. NCP and NCC were tightly coupled on time scales of minutes to days, and light was the primary driver for the variability of daily integrated metabolic rates. No correlation between CO2 levels and daily integrated NCC was observed, indicating that NCC at these sites were not significantly affected by CO2.

  3. Net primary productivity of some aquatic macrophytes in sewage-sullage mixture.

    Science.gov (United States)

    Kanungo, V K; Sinha, S; Naik, M L

    2001-07-01

    Sewage-sullage mixture from Raipur city is spread over a vast area surrounding the city. This mixture has a pH always above neutrality with high turbidity. Transparency was nil with the absence of phenolphthalein alkalinity and dissolved oxygen. Hardness was high with low nitrogen and phosphorus concentration. Human consumable. acquatic macrophytes are cultivated in such waste water. Net primary productivity of three macrophytes: Ipomoea aquatica, Marsilea quadrifolia and Nelumbo nucifera were evaluated while being cultivated in such sewage-sullage mixture. Productivity was determined either with periodic biomass removal (I. aquatica and M. quadrifolia) or through removing the biomass only once at the time of growing season (N. nucifera). Growing season productivity of up to 27.48. 19.81 and 9.49 g m(-2) and day(-1) and extrapolated productivity of up to 100.30, 72.31 and 34.64 mt. ha(-1) yr(-1) was recorded for I. aquatica. M. quadrifolia and N. nucifera respectively. Thus, these macrophytes are yielding a high amount of human consumable biomass from an area which neither be a useless wetland.

  4. Estimating Net Primary Production of Swedish Forest Landscapes by Combining Mechanistic Modeling and Remote Sensing

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Smith, Benjamin; Løfgren, Anders

    2009-01-01

    and the Beer-Lambert law. LAI estimates were compared with satellite-extrapolated field estimates of LAI, and the results were generally acceptable. NPP estimates directly from the dynamic vegetation model and estimates obtained by combining the model estimates with remote sensing information were, on average......The aim of this study was to investigate a combination of satellite images of leaf area index (LAI) with processbased vegetation modeling for the accurate assessment of the carbon balances of Swedish forest ecosystems at the scale of a landscape. Monthly climatologic data were used as inputs...... in a dynamic vegetation model, the Lund Potsdam Jena-General Ecosystem Simulator. Model estimates of net primary production (NPP) and the fraction of absorbed photosynthetic active radiation were constrained by combining them with satellite-based LAI images using a general light use efficiency (LUE) model...

  5. Environmental evidence for net methane production and oxidation in putative ANaerobic MEthanotrophic (ANME) archaea

    DEFF Research Database (Denmark)

    Lloyd, Karen; Teske, Andreas; Alperin, Marc J.

    2011-01-01

    Uncultured ANaerobic MEthanotrophic (ANME) archaea are often assumed to be obligate methanotrophs that are incapable of net methanogenesis, and are therefore used as proxies for anaerobic methane oxidation in many environments in spite of uncertainty regarding their metabolic capabilities...... versus methane production in sediments from the White Oak River estuary, North Carolina. ANME-1 consistently transcribe 16S rRNA and mRNA of methyl coenzyme M reductase (mcrA), the key gene for methanogenesis, up to 45 cm into methanogenic sediments. CARD-FISH shows that ANME-1 exist as single rod....... These results, along with a re-assessment of the published Iiterature, change the perspective to ANME-1 as methanogens that are also capable of methane oxidation....

  6. On Productions of Net-Baryons in Central Au-Au Collisions at RHIC Energies

    Directory of Open Access Journals (Sweden)

    Ya-Hui Chen

    2015-01-01

    Full Text Available The transverse momentum and rapidity distributions of net-baryons (baryons minus antibaryons produced in central gold-gold (Au-Au collisions at 62.4 and 200 GeV are analyzed in the framework of a multisource thermal model. Each source in the model is described by the Tsallis statistics to extract the effective temperature and entropy index from the transverse momentum distribution. The two parameters are used as input to describe the rapidity distribution and to extract the rapidity shift and contribution ratio. Then, the four types of parameters are used to structure some scatter plots of the considered particles in some three-dimensional (3D spaces at the stage of kinetic freeze-out, which are expected to show different characteristics for different particles and processes. The related methodology can be used in the analyses of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

  7. The SeaDataNet data products: regional temperature and salinity historical data collections

    Science.gov (United States)

    Simoncelli, Simona; Coatanoan, Christine; Bäck, Orjan; Sagen, Helge; Scoy, Serge; Myroshnychenko, Volodymyr; Schaap, Dick; Schlitzer, Reiner; Iona, Sissy; Fichaut, Michele

    2016-04-01

    Temperature and Salinity (TS) historical data collections covering the time period 1900-2013 were created for each European marginal sea (Arctic Sea, Baltic Sea, Black Sea, North Sea, North Atlantic Ocean and Mediterranean Sea) within the framework of SeaDataNet2 (SDN) EU-Project and they are now available as ODV collections through the SeaDataNet web catalog at http://sextant.ifremer.fr/en/web/seadatanet/. Two versions have been published and they represent a snapshot of the SDN database content at two different times: V1.1 (January 2014) and V2 (March 2015). A Quality Control Strategy (QCS) has been developped and continuously refined in order to improve the quality of the SDN database content and to create the best product deriving from SDN data. The QCS was originally implemented in collaboration with MyOcean2 and MyOcean Follow On projects in order to develop a true synergy at regional level to serve operational oceanography and climate change communities. The QCS involved the Regional Coordinators, responsible of the scientific assessment, the National Oceanographic Data Centers (NODC) and the data providers that, on the base of the data quality assessment outcome, checked and eventually corrected anomalies in the original data. The QCS consists of four main phases: 1) data harvesting from the central CDI; 2) file and parameter aggregation; 3) quality check analysis at regional level; 4) analysis and correction of data anomalies. The approach is iterative to facilitate the upgrade of SDN database content and it allows also the versioning of data products with the release of new regional data collections at the end of each QCS loop. SDN data collections and the QCS will be presented and the results summarized.

  8. Annual nitrate drawdown observed by SOCCOM profiling floats and the relationship to annual net community production

    Science.gov (United States)

    Johnson, Kenneth S.; Plant, Joshua N.; Dunne, John P.; Talley, Lynne D.; Sarmiento, Jorge L.

    2017-08-01

    Annual nitrate cycles have been measured throughout the pelagic waters of the Southern Ocean, including regions with seasonal ice cover and southern hemisphere subtropical zones. Vertically resolved nitrate measurements were made using in situ ultraviolet spectrophotometer (ISUS) and submersible ultraviolet nitrate analyzer (SUNA) optical nitrate sensors deployed on profiling floats. Thirty-one floats returned 40 complete annual cycles. The mean nitrate profile from the month with the highest winter nitrate minus the mean profile from the month with the lowest nitrate yields the annual nitrate drawdown. This quantity was integrated to 200 m depth and converted to carbon using the Redfield ratio to estimate annual net community production (ANCP) throughout the Southern Ocean south of 30°S. A well-defined, zonal mean distribution is found with highest values (3-4 mol C m-2 yr-1) from 40 to 50°S. Lowest values are found in the subtropics and in the seasonal ice zone. The area weighted mean was 2.9 mol C m-2 yr-1 for all regions south of 40°S. Cumulative ANCP south of 50°S is 1.3 Pg C yr-1. This represents about 13% of global ANCP in about 14% of the global ocean area.Plain Language SummaryThis manuscript reports on 40 annual cycles of nitrate observed by chemical sensors on SOCCOM profiling floats. The annual drawdown in nitrate concentration by phytoplankton is used to assess the spatial variability of annual net community production in the Southern Ocean. This ANCP is a key component of the global carbon cycle and it exerts an important control on atmospheric carbon dioxide. We show that the results are consistent with our prior understanding of Southern Ocean ANCP, which has required decades of observations to accumulate. The profiling floats now enable annual resolution of this key process. The results also highlight spatial variability in ANCP in the Southern Ocean.

  9. Net ecosystem productivity of temperate grasslands in northern China: An upscaling study

    Science.gov (United States)

    Zhang, Li; Guo, Huadong; Jia, Gensuo; Wylie, Bruce; Gilmanov, Tagir; Howard, Daniel M.; Ji, Lei; Xiao, Jingfeng; Li, Jing; Yuan, Wenping; Zhao, Tianbao; Chen, Shiping; Zhou, Guangsheng; Kato, Tomomichi

    2014-01-01

    Grassland is one of the widespread biome types globally, and plays an important role in the terrestrial carbon cycle. We examined net ecosystem production (NEP) for the temperate grasslands in northern China from 2000 to 2010. We combined flux observations, satellite data, and climate data to develop a piecewise regression model for NEP, and then used the model to map NEP for grasslands in northern China. Over the growing season, the northern China's grassland had a net carbon uptake of 158 ± 25 g C m−2 during 2000–2010 with the mean regional NEP estimate of 126 Tg C. Our results showed generally higher grassland NEP at high latitudes (northeast) than at low latitudes (central and west) because of different grassland types and environmental conditions. In the northeast, which is dominated by meadow steppes, the growing season NEP generally reached 200–300 g C m−2. In the southwest corner of the region, which is partially occupied by alpine meadow systems, the growing season NEP also reached 200–300 g C m−2. In the central part, which is dominated by typical steppe systems, the growing season NEP generally varied in the range of 100–200 g C m−2. The NEP of the northern China's grasslands was highly variable through years, ranging from 129 (2001) to 217 g C m−2 growing season−1 (2010). The large interannual variations of NEP could be attributed to the sensitivity of temperate grasslands to climate changes and extreme climatic events. The droughts in 2000, 2001, and 2006 reduced the carbon uptake over the growing season by 11%, 29%, and 16% relative to the long-term (2000–2010) mean. Over the study period (2000–2010), precipitation was significantly correlated with NEP for the growing season (R2 = 0.35, p-value < 0.1), indicating that water availability is an important stressor for the productivity of the temperate grasslands in semi-arid and arid regions in northern China. We conclude that northern temperate grasslands have the potential to

  10. Model estimates of net primary productivity, evaportranspiration, and water use efficiency in the terrestrial ecosystems of the southern United States

    Science.gov (United States)

    Hanqin Tian; Guangsheng Chen; Mingliang Liu; Chi Zhang; Ge Sun; Chaoqun Lu; Xiaofeng Xu; Wei Ren; Shufen Pan; Arthur. Chappelka

    2010-01-01

    The effects of global change on ecosystem productivity and water resources in the southern United States (SUS), a traditionally ‘water-rich’ region and the ‘timber basket’ of the country, are not well quantified. We carried out several simulation experiments to quantify ecosystem net primary productivity (NPP), evapotranspiration (ET)...

  11. Acid gas removal in synfuels production

    Energy Technology Data Exchange (ETDEWEB)

    Eickmeyer, A.G.; Gangriwala, H.A.

    1981-12-01

    The CO/sub 2/, H/sub 2/S and COS contents of gas streams of some synfuel processes and the costs for removal of these gases are tabulated. Four different types of acid gas removal processes discussed are chemisorption, physical adsorption, hybrid or combination of the first two, and sulfur conversion processes. Results of an economic study of H/sub 2/S and CO/sub 2/ removal at pressures of 1379, 2758, and 4137 kPa for 13.8 million normal m/sup 3//day of gas containing 1% H/sub 2/S and 22% CO/sub 2/. The processes considered were selective removal of H/sub 2/S with a solvent process (CATASOL 3) followed by removal of CO/sub 2/ by either the CATASOL 4A physical solvent or the CATACARB process (catalyzed hot potassium). The main feature influencing the selection of acid gas removal process are the gas composition and pressure and availability of low-level waste heat. Capital investment, utilities, and chemical costs were considered for various processes. Since the cost of commercial size synfuel process plants runs into billions of dollars, the added cost of acid gas removal must be carefully considered. (BLM)

  12. Accumulative effect of food residues on intestinal gas production.

    Science.gov (United States)

    Mego, M; Accarino, A; Malagelada, J-R; Guarner, F; Azpiroz, F

    2015-11-01

    As mean transit time in the colon is longer than the interval between meals, several consecutive meal loads accumulate, and contribute to colonic biomass. Our aim was to determine the summation effect of fermentable food residues on intestinal gas production. In eight healthy subjects, the volume of endogenous intestinal gas produced in the intestine over a 4-h period was measured by means of a wash-out technique, using an exogenous gas infusion into the jejunum (24 mL/min) and collection of the effluent via a rectal Foley catheter. The exogenous gas infused was labeled (5% SF6 ) to calculate the proportion of endogenous intestinal gas evacuated. In each subject, four experiments were performed ≥1 week apart combining a 1-day high- or low-flatulogenic diet with a test meal or fast. Basal conditions: on the low-flatulogenic diet, intestinal gas production during fasting over the 4-h study period was 609 ± 63 mL. Effect of diet: during fasting, intestinal gas production on the high-flatulogenic diet was 370 ± 146 mL greater than on the low-flatulogenic diet (p = 0.040). Effect of test meal: on the low-flatulogenic diet, intestinal gas production after the test meal was 681 ± 114 mL greater than during fasting (p = 0.001); a similar effect was observed on the high-flatulogenic diet (599 ± 174 mL more intestinal gas production after the test meal than during fasting; p = 0.021). Our data demonstrate temporal summation effects of food residues on intestinal gas production. Hence, intestinal gas production depends on pre-existing and on recent colonic loads of fermentable foodstuffs. © 2015 John Wiley & Sons Ltd.

  13. Experimental on-line platform for product conceptual design: OpenDesigNet

    Directory of Open Access Journals (Sweden)

    Teresa Magal-Royo

    2013-09-01

    Full Text Available This paper highlights the need for using specialised on-line collaborative environments by designers and product engineers who increasingly use Web 2.0 technology to search for information. Although there are professional channels and networks, there is no specific platform which helps during a new product’s conceptualisation phase. Open communication must thus be promoted and encouraged amongst design professionals and companies to form working groups thereby allowing them to work collaboratively in the most open and creative phase of product design, i.e. conceptualisation. The OpenDesigNet (ODN experimental platform has been developed so that designers and small- or medium-sized companies (SMC can access on-line collaborative tools to support the creation and promotion of new on-line products and assess their immediate social impact. This article presents some of the results obtained during the validation phase involving a platform satisfaction survey of design engineering students and has led to a first-hand assessment of the new platform’s potential impact on their professional future.

  14. Urban expansion brought stress to food security in China: Evidence from decreased cropland net primary productivity.

    Science.gov (United States)

    He, Chunyang; Liu, Zhifeng; Xu, Min; Ma, Qun; Dou, Yinyin

    2017-01-15

    Cropland net primary productivity (CNPP) is a crucial indicator of grain productivity and food security. However, assessments of the impact of urban expansion on the CNPP in China have been inadequate owing to data limitations. In this paper, our objective was to assess the impact of urban expansion on the CNPP in China from 1992 to 2015 in a spatially explicit manner. We first obtained the CNPP before urban expansion between 1992 and 2015 in China using the Carnegie-Ames-Stanford Approach (CASA) model. We then assessed the impact of urban expansion on the CNPP from 1992 to 2015 at multiple scales (the whole country, agricultural zones, and urban expansion hotspots) by combining the CNPP before urban expansion with the urban land coverage time series extracted from multi-source remotely sensed data. We found that the total loss of the CNPP due to urban expansion from 1992 to 2015 was 13.77TgC, which accounts for 1.88% of the CNPP before urban expansion in China. This CNPP loss resulted in a 12.45-million-ton decrease in grain production in China, corresponding to a reduction in the mean annual grain self-sufficiency rate of 2%. Therefore, we concluded that rapid urban expansion from 1992 to 2015 caused stress to China's food security. We suggest that it is still vital for China to effectively protect cropland to improve the urbanization level to 60% by 2020. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Organisms Composing an Experimental Coral Reef Community from Mo'orea, French Polynesia, Exhibit Taxon-Specific Net Production: Net Calcification Ratios

    Directory of Open Access Journals (Sweden)

    Coulson A. Lantz

    2017-09-01

    Full Text Available Current research on coral reefs seeks to link the responses to anthropogenic stressors (such as global warming and ocean acidification [OA] among differing functional levels of biological organization. While experimental studies have identified ex situ taxon-specific responses to OA and global warming, isolating and connecting these effects in situ at the community-level has proved difficult. The difficulties arise from the large number of naturally varying parameters affecting corals reefs, such as light intensity and seawater residence time that affect net community production and calcification. To control variation in seawater residence time and allow light intensity to vary naturally, experimental outer reef (17-m depth benthic communities composed of calcified algae, corals, and reef pavement were constructed in large outdoor flumes in Mo'orea, French Polynesia. Net community production (P, net community calcification (G, the ratio of P/G (P/Gratio, and slope of P regressed on G (P/Gslope were calculated for the communities, and concurrently for the constituent members under the same temperature, light, and flow conditions. P and G, for both the communities and constituent members, were correlated positively with light intensity, whereas P/Gratio and P/Gslope were unaffected by light intensity. P/Gratios and P/Gslopes exhibited values that were specific to each community member. These results suggest that the P/Gratio and P/Gslope may be unaffected by natural variability in light intensity and could serve as useful metrics to relate responses at the taxon and community level, which is an important step in assessing the effects of environmental changes on coral reefs.

  16. 78 FR 59650 - Subzone 9F, Authorization of Production Activity, The Gas Company, LLC dba Hawai'i Gas...

    Science.gov (United States)

    2013-09-27

    ... Foreign-Trade Zones Board Subzone 9F, Authorization of Production Activity, The Gas Company, LLC dba Hawai'i Gas, (Synthetic Natural Gas), Kapolei, Hawaii On May 22, 2013, The Gas Company, LLC dba Hawai'i Gas submitted a notification of proposed production activity to the Foreign-Trade Zones (FTZ) Board...

  17. Process for production desulfurized of synthesis gas

    Science.gov (United States)

    Wolfenbarger, James K.; Najjar, Mitri S.

    1993-01-01

    A process for the partial oxidation of a sulfur- and silicate-containing carbonaceous fuel to produce a synthesis gas with reduced sulfur content which comprises partially oxidizing said fuel at a temperature in the range of 1900.degree.-2600.degree. F. in the presence of a temperature moderator, an oxygen-containing gas and a sulfur capture additive which comprises a calcium-containing compound portion, a sodium-containing compound portion, and a fluoride-containing compound portion to produce a synthesis gas comprising H.sub.2 and CO with a reduced sulfur content and a molten slag which comprises (1) a sulfur-containing sodium-calcium-fluoride silicate phase; and (2) a sodium-calcium sulfide phase.

  18. Sensitivity Analysis of Methane Hydrate Reservoirs: Effects of Reservoir Parameters on Gas Productivity and Economics

    Science.gov (United States)

    Anderson, B. J.; Gaddipati, M.; Nyayapathi, L.

    2008-12-01

    This paper presents a parametric study on production rates of natural gas from gas hydrates by the method of depressurization, using CMG STARS. Seven factors/parameters were considered as perturbations from a base-case hydrate reservoir description based on Problem 7 of the International Methane Hydrate Reservoir Simulator Code Comparison Study led by the Department of Energy and the USGS. This reservoir is modeled after the inferred properties of the hydrate deposit at the Prudhoe Bay L-106 site. The included sensitivity variables were hydrate saturation, pressure (depth), temperature, bottom-hole pressure of the production well, free water saturation, intrinsic rock permeability, and porosity. A two-level (L=2) Plackett-Burman experimental design was used to study the relative effects of these factors. The measured variable was the discounted cumulative gas production. The discount rate chosen was 15%, resulting in the gas contribution to the net present value of a reservoir. Eight different designs were developed for conducting sensitivity analysis and the effects of the parameters on the real and discounted production rates will be discussed. The breakeven price in various cases and the dependence of the breakeven price on the production parameters is given in the paper. As expected, initial reservoir temperature has the strongest positive effect on the productivity of a hydrate deposit and the bottom-hole pressure in the production well has the strongest negative dependence. Also resulting in a positive correlation is the intrinsic permeability and the initial free water of the formation. Negative effects were found for initial hydrate saturation (at saturations greater than 50% of the pore space) and the reservoir porosity. These negative effects are related to the available sensible heat of the reservoir, with decreasing productivity due to decreasing available sensible heat. Finally, we conclude that for the base case reservoir, the break-even price (BEP

  19. Assessment of net primary productivity over India using Indian geostationary satellite (INSAT-3A) data

    Science.gov (United States)

    Goroshi, S. K.; Singh, R. P.; Pradhan, R.; Parihar, J. S.

    2014-11-01

    Polar orbiting satellites (MODIS and SPOT) have been commonly used to measure terrestrial Net Primary Productivity (NPP) at regional/global scale. Charge Coupled Device (CCD) instrument on geostationary INSAT-3A platform provides a unique opportunity for continuous monitoring of ecosystem pattern and process study. An improved Carnegie-Ames-Stanford Approach (iCASA) model is one of the most expedient and precise ecosystem models to estimate terrestrial NPP. In this paper, an assessment of terrestrial NPP over India was carried out using the iCASA ecosystem model based on the INSAT CCD derived Normalized Difference Vegetation Index (NDVI) with multisource meteorological data for the year 2009. NPP estimated from the INSAT CCD followed the characteristic growth profile of most of the vegetation types in the country. NPP attained maximum during August and September, while minimum in April. Annual NPP for different vegetation types varied from 1104.55 gC m-2 year-1 (evergreen broadleaf forest) to 231.9 gC m-2 year-1 (grassland) with an average NPP of 590 gC m-2 year-1. We estimated 1.9 PgC of net carbon fixation over Indian landmass in 2009. Biome level comparison between INSAT derived NPP and MODIS NPP indicated a good agreement with the Willmott's index of agreement (d) ranging from 0.61 (Mixed forest) to 0.99 (Open Shrubland). Our findings are consistent with the earlier NPP studies in India and indicate that INSAT derived NPP has the capability to detect spatial and temporal variability of terrestrial NPP over a wide range of terrestrial ecosystems in India. Thus INSAT-3A data can be used as one of the potential satellite data source for accurate biome level carbon estimation in India.

  20. The Central Logic Board for the KM3NeT detector: Design and production

    Energy Technology Data Exchange (ETDEWEB)

    Musico, P., E-mail: Paolo.Musico@ge.infn.it

    2016-07-11

    The KM3NeT deep sea neutrino observatory will include a very large number of multi-Photomultiplier (PMT) optical modules (DOM) to detect the Cherenkov light generated by secondary particles produced in neutrino interactions. The Central Logic Board (CLB) has been developed to acquire timing and amplitude information from the PMT signals, implementing time-to-digital conversion (TDC) with time over threshold (TOT) technique. The board is also used to configure all the DOM subsystems, to assist in the DOM position and orientation, calibration and to monitor temperature and humidity in the DOM itself. All the collected data are transmitted to shore using a wide-bandwidth optical network. Moreover, through the optical network, all the DOMs are kept synchronized in time within 1 ns precision using the White Rabbit (WR) Precision Time Protocol (PTP) over an Ethernet connection. A large Field Programmable Gate Array (FPGA) has been adopted to implement all the specifications witht the requested performances. The CLB will be also used in the base container of the detection unit (DU) to set-up and monitor all the requested functionalities: in this scenario a dedicated firmware and software will be deployed on board. The design has been started in early 2013 and several prototypes have been developed. After deep test carried on in different EU laboratories, the final mass production batch of 600 boards has been ordered and built: all the CLB are now ready for integration in the DOMs and base containers. The first two KM3NeT DU will be deployed in summer 2015 and all other units are in advanced stage of integration.

  1. Numerical Simulation of Shale Gas Production with Thermodynamic Calculations Incorporated

    KAUST Repository

    Urozayev, Dias

    2015-06-01

    In today’s energy sector, it has been observed a revolutionary increase in shale gas recovery induced by reservoir fracking. So-called unconventional reservoirs became profitable after introducing a well stimulation technique. Some of the analysts expect that shale gas is going to expand worldwide energy supply. However, there is still a lack of an efficient as well as accurate modeling techniques, which can provide a good recovery and production estimates. Gas transports in shale reservoir is a complex process, consisting of slippage effect, gas diffusion along the wall, viscous flow due to the pressure gradient. Conventional industrial simulators are unable to model the flow as the flow doesn’t follow Darcy’s formulation. It is significant to build a unified model considering all given mechanisms for shale reservoir production study and analyze the importance of each mechanism in varied conditions. In this work, a unified mathematical model is proposed for shale gas reservoirs. The proposed model was build based on the dual porosity continuum media model; mass conservation equations for both matrix and fracture systems were build using the dusty gas model. In the matrix, gas desorption, Knudsen diffusion and viscous flow were taken into account. The model was also developed by implementing thermodynamic calculations to correct for the gas compressibility, or to obtain accurate treatment of the multicomponent gas. Previously, the model was built on the idealization of the gas, considering every molecule identical without any interaction. Moreover, the compositional variety of shale gas requires to consider impurities in the gas due to very high variety. Peng-Robinson equation of state was used to com- pute and correct for the gas density to pressure relation by solving the cubic equation to improve the model. The results show that considering the compressibility of the gas will noticeably increase gas production under given reservoir conditions and slow down

  2. Challenges, uncertainties and issues facing gas production from gas hydrate deposits

    Energy Technology Data Exchange (ETDEWEB)

    Moridis, G.J.; Collett, T.S.; Pooladi-Darvish, M.; Hancock, S.; Santamarina, C.; Boswell, R.; Kneafsey, T.; Rutqvist, J.; Kowalsky, M.; Reagan, M.T.; Sloan, E.D.; Sum, A.K.; Koh, C.

    2010-11-01

    The current paper complements the Moridis et al. (2009) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas hydrate petroleum system, to discuss advances, requirement and suggested practices in gas hydrate (GH) prospecting and GH deposit characterization, and to review the associated technical, economic and environmental challenges and uncertainties, including: the accurate assessment of producible fractions of the GH resource, the development of methodologies for identifying suitable production targets, the sampling of hydrate-bearing sediments and sample analysis, the analysis and interpretation of geophysical surveys of GH reservoirs, well testing methods and interpretation of the results, geomechanical and reservoir/well stability concerns, well design, operation and installation, field operations and extending production beyond sand-dominated GH reservoirs, monitoring production and geomechanical stability, laboratory investigations, fundamental knowledge of hydrate behavior, the economics of commercial gas production from hydrates, and the associated environmental concerns.

  3. Interannual variability in net community production at the Western Antarctic Peninsula region (1997-2014)

    Science.gov (United States)

    Li, Zuchuan; Cassar, Nicolas; Huang, Kuan; Ducklow, Hugh; Schofield, Oscar

    2016-07-01

    In this study, we examined the interannual variability of net community production (NCP) in the Western Antarctic Peninsula (WAP) using in situ O2/Ar-NCP estimates (2008-2014) and satellite data (SeaWiFS and MODIS-Aqua) from 1997 to 2014. We found that NCP generally first peaks offshore and follows sea-ice retreat from offshore to inshore. Annually integrated NCP (ANCP) displays an onshore-to-offshore gradient, with coastal and shelf regions up to 8 times more productive than offshore regions. We examined potential drivers of interannual variability in the ANCP using an Empirical Orthogonal Function (EOF) analysis. The EOF's first mode explains ˜50% of the variance, with high interannual variability observed seaward of the shelf break. The first principal component is significantly correlated with the day of sea-ice retreat (R = -0.58, p Oscillation (ENSO) climate indices in austral spring. Although the most obvious pathway by which the day of sea-ice retreat influences NCP is by controlling light availability early in the growing season, we found that the effect of day of sea-ice retreat on NCP persists throughout the growing season, suggesting that additional controls, such as iron availability, are preconditioned or correlated to the day of sea-ice retreat.

  4. Climate change imposes phenological trade-offs on forest net primary productivity

    Science.gov (United States)

    Duveneck, Matthew J.; Thompson, Jonathan R.

    2017-09-01

    Climate warming is expected to lengthen growing seasons of temperate forest ecosystems and increase gross primary productivity. Simultaneously, warming is expected to increase summer ecosystem respiration, which could offset gains accrued from longer growing seasons. These responses have been observed during anomalously warm years, but the role of future climate change on phenological trade-offs and how they affect net primary productivity (NPP) at regional scales in temperate forests remain unexplored. We simulated scenarios of climate change on monthly forest NPP throughout 18 million hectares of temperate forests in New England, USA, through year 2100. Using an ecophysiological model coupled to a forest landscape model, we simulated scenarios of climate change on monthly NPP. A high emission scenario (RCP 8.5), resulted in longer growing seasons that offset midsummer ecosystem respiration costs and produced greater annual NPP throughout the study landscape compared to simulations using the current climate. In spring and autumn months, temperature was positively associated with greater NPP; in summer months, the relationship was negative. Spatially, the greatest increase in NPP occurred in the warmer southern region under a warm climate scenario with increased precipitation. Under a warm scenario with drier conditions, the greatest increase in NPP occurred in the cooler northern region. Phenological trade-offs will affect NPP of future forests and their potential to serve as a negative feedback to climate change. Barring other limitations, longer growing seasons will offset greater respiratory demands and contribute to increases in NPP throughout the temperate forests of New England in the future.

  5. Contrasting net primary productivity and carbon distribution between neighbouring stands of Quercus robur and Pinus sylvestris

    Energy Technology Data Exchange (ETDEWEB)

    Yuste, J. C.; Konopka, B.; Janssens, I. A.; Coenen, K.; Xiao, C. W.; Ceulemans, R. [University of Antwerp, Dept. of Biology, Research Group of Plant and Vegetation Ecology, Wilrijk (Belgium)

    2005-06-01

    Complete net primary production (NPP) estimates for two species (a 67 year-old pendulate oak stand and a neighbouring 74 year-old Scotch pine stand) with contrasting vegetation types, growing within the Belgian Campine region, are reported. Although tree density and tree height were lower in the oak stand, standing biomass was slightly higher than in the pine stand, indicating that individual oak trees contained more biomass than pine trees of similar diameter. A higher rate of soil organic matter accumulation was confirmed under pine trees than under oaks, suggesting an age-related decline in productivity due to nutrient limitation. The poor decomposition of pine litter resulting in the accumulation of organic matter, coupled with the already nutrient-poor soil conditions, resulted in a decrease in total NPP over time. In the oak stand, litter was quicker to decay, soil acidity was less severe, therefore, organic matter did not accumulate and nutrients were recycled. This explains the higher NPP in the oak stand. 48 refs., 5 tabs., 7 figs.

  6. Impacts of China's Three Gorges Dam Project on net primary productivity in the reservoir area.

    Science.gov (United States)

    Xu, Xibao; Tan, Yan; Yang, Guishan; Li, Hengpeng; Su, Weizhong

    2011-10-15

    China's Three Gorges Dam Project (TGP) is the world's largest hydroelectric power project, and as a consequence the reservoir area is at risk of ecological degradation. This study uses net primary productivity (NPP) as an important indicator of the reservoir ecosystem's productivity to estimate the impacts of the TGP in the local resettlement region of the Three Gorges Reservoir Area (TGRA) over the 2000-2010 period. The modeling method is based upon the Carnegie Ames Stanford Approach (CASA) terrestrial carbon model and uses Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data for modeling simulation. The results demonstrate that total NPP in the resettlement region decreased by 8.0% (632.8Gg) from 2000 to 2010. The impact of the TGP on NPP is mainly mediated by land-use change brought about by the large-scale inundation of land and subsequent massive resettlement of both rural and urban residents. Nearby resettlement, land inundation, and relocation of old urban centers and affiliated urban dwellers are responsible for 54.3%, 28.0%, and 5.8% respectively of total NPP reduction in the resettlement region over the study period. The major national ecological projects implemented in the TGRA since 1998 have played a key role in offsetting the negative impacts of the TGP on NPP in the region. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Aboveground Net Primary Productivity in a Riparian Wetland Following Restoration of Hydrology.

    Science.gov (United States)

    Koontz, Melissa; Lundberg, Christopher; Lane, Robert; Day, John; Pezeshki, Reza

    2016-02-04

    This research presents the initial results of the effects of hydrological restoration on forested wetlands in the Mississippi alluvial plain near Memphis, Tennessee. Measurements were carried out in a secondary channel, the Loosahatchie Chute, in which rock dikes were constructed in the 1960s to keep most flow in the main navigation channel. In 2008-2009, the dikes were notched to allow more flow into the secondary channel. Study sites were established based on relative distance downstream of the notched dikes. Additionally, a reference site was established north of the Loosahatchie Chute where the dikes remained unnotched. We compared various components of vegetation composition and productivity at sites in the riparian wetlands for two years. Salix nigra had the highest Importance Value at every site. Species with minor Importance Values were Celtis laevigata, Acer rubrum, and Plantanus occidentalis. Productivity increased more following the introduction of river water in affected sites compared to the reference. Aboveground net primary productivity was highest at the reference site (2926 ± 458.1 g·m(-2)·year(-1)), the intact site; however, there were greater increase at the sites in the Loosahatchie Chute, where measurements ranged from 1197.7 ± 160.0 g m(-2)·year(-1)·to 2874.2 ± 794.0 g·m(-2)·year(-1). The site furthest from the notching was the most affected. Pulsed inputs into these wetlands may enhance forested wetland productivity. Continued monitoring will quantify impacts of restored channel hydrology along the Mississippi River.

  8. Climatic and oceanic forcing of new, net, and diatom production in the North Water

    Science.gov (United States)

    Tremblay, Jean-Eric; Gratton, Yves; Fauchot, Juliette; Price, Neil M.

    New, net, and diatom production in the North Water were estimated during May to July 1998 from in vitro measurements of nitrate uptake and mesoscale temporal changes in the inventories of nitrate, silicate, oxygen, and inorganic carbon (DIC). Sampling stations were divided into two domains according to the position of the dominant water types: the silicate-rich Arctic water (SRAW) and Baffin Bay Water (BBW). BBW dominated in the southeast and was associated with relatively shallow upper mixed layers (UMLs) and weak horizontal advection. A phytoplankton bloom started in late April in BBW and grew slowly over 7 weeks, during which time the build-up of particulate organic nitrogen and carbon accounted for ca. 80% of the nitrate and DIC deficit, respectively. Over half of the new production (1.37 g C m -2 d -1) during this period was attributed to wind-driven replenishment of nitrate in the euphotic zone. The bloom culminated when seasonally declining winds and rising temperatures severed the UML from the deep nutrient reservoir. The same change in weather induced ice melt, stratification, and bloom development in northern SRAW, which had previously been characterized by deep UMLs. Collectively, the results imply that the timing and magnitude of blooms in the North Water are controlled by a succession of oceanic and climatic forcings. New C production in the North Water during April to July (1.11 g C m -2 d -1) was an order of magnitude higher than in adjacent waters and up to 8 times higher than in the Northeast Water polynya. As much as 80% of this production was mediated by diatoms >5 μm, suggesting potentially high and efficient C transfer to the herbivorous food web and deep waters.

  9. Aboveground Net Primary Productivity in a Riparian Wetland Following Restoration of Hydrology

    Directory of Open Access Journals (Sweden)

    Melissa Koontz

    2016-02-01

    Full Text Available This research presents the initial results of the effects of hydrological restoration on forested wetlands in the Mississippi alluvial plain near Memphis, Tennessee. Measurements were carried out in a secondary channel, the Loosahatchie Chute, in which rock dikes were constructed in the 1960s to keep most flow in the main navigation channel. In 2008–2009, the dikes were notched to allow more flow into the secondary channel. Study sites were established based on relative distance downstream of the notched dikes. Additionally, a reference site was established north of the Loosahatchie Chute where the dikes remained unnotched. We compared various components of vegetation composition and productivity at sites in the riparian wetlands for two years. Salix nigra had the highest Importance Value at every site. Species with minor Importance Values were Celtis laevigata, Acer rubrum, and Plantanus occidentalis. Productivity increased more following the introduction of river water in affected sites compared to the reference. Aboveground net primary productivity was highest at the reference site (2926 ± 458.1 g·m−2·year−1, the intact site; however, there were greater increase at the sites in the Loosahatchie Chute, where measurements ranged from 1197.7 ± 160.0 g m−2·year−1·to 2874.2 ± 794.0 g·m−2·year−1. The site furthest from the notching was the most affected. Pulsed inputs into these wetlands may enhance forested wetland productivity. Continued monitoring will quantify impacts of restored channel hydrology along the Mississippi River.

  10. Petri Net Modeling and Decomposition Method for Solving Production Scheduling Problems

    National Research Council Canada - National Science Library

    NISHI, Tatsushi; MAENO, Ryota

    2007-01-01

    Considering the need to develop general scheduling problem solver, the recent integration of Petri Nets as modeling tools into effective optimization methods for scheduling problems is very promising...

  11. Liquefied natural gas production at Hammerfest: A transforming marine community

    NARCIS (Netherlands)

    Bets, van L.K.J.; Tatenhove, van J.P.M.; Mol, A.P.J.

    2016-01-01

    Global energy demand and scarce petroleum resources require communities to adapt to a rapidly changing Arctic environment, but as well to a transforming socio-economic environment instigated by oil and gas development. This is illustrated by liquefied natural gas production by Statoil at Hammerfest,

  12. Differences in net global warming potential and greenhouse gas intensity between major rice-based cropping systems in China.

    Science.gov (United States)

    Xiong, Zhengqin; Liu, Yinglie; Wu, Zhen; Zhang, Xiaolin; Liu, Pingli; Huang, Taiqing

    2015-12-02

    Double rice (DR) and upland crop-single rice (UR) systems are the major rice-based cropping systems in China, yet differences in net global warming potential (NGWP) and greenhouse gas intensity (GHGI) between the two systems are poorly documented. Accordingly, a 3-year field experiment was conducted to simultaneously measure methane (CH4) and nitrous oxide (N2O) emissions and changes in soil organic carbon (SOC) in oil rape-rice-rice and wheat-rice (representing DR and UR, respectively) systems with straw incorporation (0, 3 and 6 t/ha) during the rice-growing seasons. Compared with the UR system, the annual CH4, N2O, grain yield and NGWP were significantly increased in the DR system, though little effect on SOC sequestration or GHGI was observed without straw incorporation. Straw incorporation increased CH4 emission and SOC sequestration but had no significant effect on N2O emission in both systems. Averaged over the three study years, straw incorporation had no significant effect on NGWP and GHGI in the UR system, whereas these parameters were greatly increased in the DR system, i.e., by 108% (3 t/ha) and 180% (6 t/ha) for NGWP and 103% (3 t/ha) and 168% (6 t/ha) for GHGI.

  13. Productivity gains and greenhouse gas emissions intensity in dairy systems

    NARCIS (Netherlands)

    Gerber, P.; Vellinga, Th.V.; Opio, C.; Steinfeld, H.

    2011-01-01

    This paper explores the relationship between productivity of dairy production and greenhouse gas (GHG) emissions on a global scale. A Life Cycle Assessment (LCA) methodology was used to assess GHG emissions from dairy production and processing chains. Milk yield expressed as kg fat and protein

  14. Map service: United States Oil and Gas Production 2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map service displays present and past oil and gas production in the United States, as well as the location and intensity of exploratory drilling outside...

  15. Evaluation of the gas production economics of the gas hydrate cyclic thermal injection model

    Energy Technology Data Exchange (ETDEWEB)

    Kuuskraa, V.A.; Hammersheimb, E.; Sawyer, W.

    1985-05-01

    The objective of the work performed under this directive is to assess whether gas hydrates could potentially be technically and economically recoverable. The technical potential and economics of recovering gas from a representative hydrate reservoir will be established using the cyclic thermal injection model, HYDMOD, appropriately modified for this effort, integrated with economics model for gas production on the North Slope of Alaska, and in the deep offshore Atlantic. The results from this effort are presented in this document. In Section 1, the engineering cost and financial analysis model used in performing the economic analysis of gas production from hydrates -- the Hydrates Gas Economics Model (HGEM) -- is described. Section 2 contains a users guide for HGEM. In Section 3, a preliminary economic assessment of the gas production economics of the gas hydrate cyclic thermal injection model is presented. Section 4 contains a summary critique of existing hydrate gas recovery models. Finally, Section 5 summarizes the model modification made to HYDMOD, the cyclic thermal injection model for hydrate gas recovery, in order to perform this analysis.

  16. Biomass rather than growth rate determines variation in net primary production by giant kelp.

    Science.gov (United States)

    Reed, Daniel C; Rassweiler, Andrew; Arkema, Katie K

    2008-09-01

    Net primary production (NPP) is influenced by disturbance-driven fluctuations in foliar standing crop (FSC) and resource-driven fluctuations in rates of recruitment and growth, yet most studies of NPP have focused primarily on factors influencing growth. We quantified NPP, FSC, recruitment, and growth rate for the giant kelp, Macrocystis pyrifera, at three kelp forests in southern California, U.S.A., over a 54-month period and determined the relative roles of FSC, recruitment, and growth rate in contributing to variation in annual NPP. Net primary production averaged between 0.42 and 2.38 kg dry mass x m(-2) x yr(-1) at the three sites. The initial FSC present at the beginning of the growth year and the recruitment of new plants during the year explained 63% and 21% of the interannual variation observed in NPP, respectively. The previous year's NPP and disturbance from waves collectively accounted for 80% of the interannual variation in initial FSC. No correlation was found between annual growth rate (i.e., the amount of new kelp mass produced per unit of existing kelp mass) and annual NPP (i.e., the amount of new kelp mass produced per unit area of ocean bottom), largely because annual growth rate was consistent compared to initial FSC and recruitment, which fluctuated greatly among years and sites. Although growth rate was a poor predictor of variation in annual NPP, it was principally responsible for the high mean values observed for NPP by Macrocystis. These high mean values reflected rapid growth (average of approximately 2% per day) of a relatively small standing crop (maximum annual mean = 444 g dry mass/m2) that replaced itself approximately seven times per year. Disturbance-driven variability in FSC may be generally important in explaining variation in NPP, yet it is rarely examined because cycles of disturbance and recovery occur over timescales of decades or more in many systems. Considerable insight into how variation in FSC drives variation in NPP may

  17. Gas Production in the MEGAPIE Spallation Target

    OpenAIRE

    Thiollière, Nicolas; Zanini, Luca; David, Jean-Christophe; Eikenberg, Jost; Guertin, Arnaud; Konobeyev, Alexander Yu.; Lemaire, Sébastien; Panebianco, Stefano

    2011-01-01

    International audience; The MEGAwatt PIlot Experiment (MEGAPIE) project was started in 2000 to design, build, and operate a liquid lead-bismuth eutectic (LBE) spallation neutron target at the power level of 1 MW. The target was irradiated for 4 months in 2006 at the Paul Scherrer Institute in Switzerland. Gas samples wereextracted in various phases of operation and analyzed by g spectroscopy, leading to the determination of the main radioactive isotopes released from the LBE. Comparison with ...

  18. A windowless gas target for secondary beam production

    CERN Document Server

    Kishida, T; Shibata, M; Watanabe, H; Tsutsumi, T; Motomura, S; Ideguchi, E; Zhou, X H; Morikawa, T; Kubo, T; Ishihara, M

    1999-01-01

    A windowless gas target was developed for the production of secondary high-spin isomer beams (HSIB). An sup 1 sup 6 O target in the compound form of CO sub 2 gas was used to produce a sup 1 sup 4 sup 5 sup m Sm beam by using an sup 1 sup 6 O( sup 1 sup 3 sup 6 Xe, 7n) sup 1 sup 4 sup 5 sup m Sm reaction. The target gas pressure was kept constant at 50 Torr. A target thickness of about 1 mg/cm sup 2 was achieved with a 10 cm target length. Gas was recirculated and the consumption was very little.

  19. Improved assessment of gross and net primary productivity of Canada's landmass

    Science.gov (United States)

    Gonsamo, Alemu; Chen, Jing M.; Price, David T.; Kurz, Werner A.; Liu, Jane; Boisvenue, Céline; Hember, Robbie A.; Wu, Chaoyang; Chang, Kuo-Hsien

    2013-12-01

    assess Canada's gross primary productivity (GPP) and net primary productivity (NPP) using boreal ecosystem productivity simulator (BEPS) at 250 m spatial resolution with improved input parameter and driver fields and phenology and nutrient release parameterization schemes. BEPS is a process-based two-leaf enzyme kinetic terrestrial ecosystem model designed to simulate energy, water, and carbon (C) fluxes using spatial data sets of meteorology, remotely sensed land surface variables, soil properties, and photosynthesis and respiration rate parameters. Two improved key land surface variables, leaf area index (LAI) and land cover type, are derived at 250 m from Moderate Resolution Imaging Spectroradiometer sensor. For diagnostic error assessment, we use nine forest flux tower sites where all measured C flux, meteorology, and ancillary data sets are available. The errors due to input drivers and parameters are then independently corrected for Canada-wide GPP and NPP simulations. The optimized LAI use, for example, reduced the absolute bias in GPP from 20.7% to 1.1% for hourly BEPS simulations. Following the error diagnostics and corrections, daily GPP and NPP are simulated over Canada at 250 m spatial resolution, the highest resolution simulation yet for the country or any other comparable region. Total NPP (GPP) for Canada's land area was 1.27 (2.68) Pg C for 2008, with forests contributing 1.02 (2.2) Pg C. The annual comparisons between measured and simulated GPP show that the mean differences are not statistically significant (p > 0.05, paired t test). The main BEPS simulation error sources are from the driver fields.

  20. Impact of Icebergs on Net Primary Productivity in the Southern Ocean

    Science.gov (United States)

    Wu, Shuang-Ye; Hou, Shugui

    2017-04-01

    Productivity in the Southern Ocean (SO) is iron-limited, and supply of iron dissolved from aeolian dust is believed to be the main source from outside the marine environment. However, recent studies show that icebergs could provide comparable amount of bioavailable iron to the SO as aeolian dust. In addition, small scale areal studies suggest increased concentrations of chlorophyll, krill, and seabirds surrounding icebergs. Based on previous research, this study aims to examine whether iceberg occurrence has a significant impact on marine productivity at the scale of the SO, using remote sensing data of iceberg occurrences and ocean net primary productivity (NPP) covering the period 2002-2014. The impacts of both large and small icebergs are examined in four major ecological zones of the SO: the continental shelf zone (CSZ), the seasonal ice zone (SIZ), the permanent open ocean zone (POOZ) and the polar front zone (PFZ). We found that both large and small icebergs have an observable positive impact on NPP, but their impacts vary in different zones. Small icebergs on average increase NPP in most iron deficient zones: by 21% for the SIZ, 16% for the POOZ, and 12% for the PFZ, but have relatively small effect in the CSZ where iron is supplied from melt water and sediment input from the continent. Large icebergs on average increase the NPP by about 10%. Their impacts are stronger at higher latitudes, where they are more concentrated. From 1992-2014, there is a significant increasing trend for both small and large icebergs. The increase was most rapid in the early 2000s, and has levelled off since then. As the climate continues to warm, the Antarctic Ice Sheet is expected to experience increased mass loss as a whole, which could lead to more icebergs in the region. Based on our study, this could result in higher level of NPP in the SO as a whole, providing a negative feedback for global warming.

  1. Net primary productivity of subalpine meadows in Yosemite National Park in relation to climate variability

    Science.gov (United States)

    Moore, Peggy E.; Van Wagtendonk, Jan W.; Yee, Julie L.; McClaran, Mitchel P.; Cole, David N.; McDougald, Neil K.; Brooks, Matthew L.

    2013-01-01

    Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to describe patterns and variability in aboveground live vascular plant biomass in relation to climatic factors. We harvested aboveground biomass at peak growth from four 64-m2 plots each in xeric, mesic, and hydric meadows annually from 1994 to 2000. Data from nearby weather stations provided independent variables of spring snow water content, snow-free date, and thawing degree days for a cumulative index of available energy. We assembled these climatic variables into a set of mixed effects analysis of covariance models to evaluate their relationships with annual aboveground net primary productivity (ANPP), and we used an information theoretic approach to compare the quality of fit among candidate models. ANPP in the xeric meadow was negatively related to snow water content and thawing degree days and in the mesic meadow was negatively related to snow water content. Relationships between ANPP and these 2 covariates in the hydric meadow were not significant. Increasing snow water content may limit ANPP in these meadows if anaerobic conditions delay microbial activity and nutrient availability. Increased thawing degree days may limit ANPP in xeric meadows by prematurely depleting soil moisture. Large within-year variation of ANPP in the hydric meadow limited sensitivity to the climatic variables. These relationships suggest that, under projected warmer and drier conditions, ANPP will increase in mesic meadows but remain unchanged in xeric meadows because declines associated with increased temperatures would offset the increases from decreased snow water content.

  2. Evaluation of modelled net primary production using MODIS and landsat satellite data fusion.

    Science.gov (United States)

    Jay, Steven; Potter, Christopher; Crabtree, Robert; Genovese, Vanessa; Weiss, Daniel J; Kraft, Maggi

    2016-12-01

    To improve estimates of net primary production for terrestrial ecosystems of the continental United States, we evaluated a new image fusion technique to incorporate high resolution Landsat land cover data into a modified version of the CASA ecosystem model. The proportion of each Landsat land cover type within each 0.004 degree resolution CASA pixel was used to influence the ecosystem model result by a pure-pixel interpolation method. Seventeen Ameriflux tower flux records spread across the country were combined to evaluate monthly NPP estimates from the modified CASA model. Monthly measured NPP data values plotted against the revised CASA model outputs resulted in an overall R(2) of 0.72, mainly due to cropland locations where irrigation and crop rotation were not accounted for by the CASA model. When managed and disturbed locations are removed from the validation, the R(2) increases to 0.82. The revised CASA model with pure-pixel interpolated vegetation index performed well at tower sites where vegetation was not manipulated or managed and had not been recently disturbed. Tower locations that showed relatively low correlations with CASA-estimated NPP were regularly disturbed by either human or natural forces.

  3. Methodology for the estimation of terrestrial net primary production from remotely sensed data

    Science.gov (United States)

    Ruimy, A.; Saugier, B.; Dedieu, G.

    1994-03-01

    Kumar and Monteith's (1981) model for the remote sensing of crop growth has been used to estimate continental net primary productivity (NPP) as well as its seasonal and spatial variations. The model assumes a decomposition of NPP into independent parameters such as incident solar radiation (S0), radiation absorption efficiency by canopies (ƒ), and conversion efficiency of absorbed radiation into organic dry matter (e). The precision on some of the input parameters has been improved, compared to previous uses of this model at a global scale: remote sensing data used to derive ƒ have been calibrated, corrected of some atmospheric effects, and filtered; e has been considered as biome-dependent and derived from literature data. The resulting global NPP (approximatively 60 GtC per year) is within the range of values given in the literature. However, mean NPP estimates per biome do not agree with the literature (in particular, the estimation for tropical rain forests NPP is much lower and for cultivations much higher than field estimates), which results in zonal and seasonal variations of continental NPP giving more weight to the temperate northern hemisphere than to the equatorial zone.

  4. Estimating Green Net National Product for Puerto Rico: An Economic Measure of Sustainability.

    Science.gov (United States)

    Wu, Shanshan; Heberling, Matthew T

    2016-04-01

    This paper presents the data sources and methodology used to estimate Green Net National Product (GNNP), an economic metric of sustainability, for Puerto Rico. Using the change in GNNP as a one-sided test of weak sustainability (i.e., positive growth in GNNP is not enough to show the economy is sustainable), we measure the movement away from sustainability by examining the change in GNNP from 1993 to 2009. In order to calculate GNNP, we require both economic and natural capital data, but limited data for Puerto Rico require a number of simplifying assumptions. Based on the environmental challenges faced by Puerto Rico, we include damages from air emissions and solid waste, the storm protection value of mangroves and the value of extracting crushed stone as components in the depreciation of natural capital. Our estimate of GNNP also includes the value of time, which captures the effects of technological progress. The results show that GNNP had an increasing trend over the 17 years studied with two periods of negative growth (2004-2006 and 2007-2008). Our additional analysis suggests that the negative growth in 2004-2006 was possibly due to a temporary economic downturn. However, the negative growth in 2007-2008 was likely from the decline in the value of time, suggesting the island of Puerto Rico was moving away from sustainability during this time.

  5. Evaluation of modelled net primary production using MODIS and landsat satellite data fusion

    Directory of Open Access Journals (Sweden)

    Steven Jay

    2016-06-01

    Full Text Available Abstract Background To improve estimates of net primary production for terrestrial ecosystems of the continental United States, we evaluated a new image fusion technique to incorporate high resolution Landsat land cover data into a modified version of the CASA ecosystem model. The proportion of each Landsat land cover type within each 0.004 degree resolution CASA pixel was used to influence the ecosystem model result by a pure-pixel interpolation method. Results Seventeen Ameriflux tower flux records spread across the country were combined to evaluate monthly NPP estimates from the modified CASA model. Monthly measured NPP data values plotted against the revised CASA model outputs resulted in an overall R2 of 0.72, mainly due to cropland locations where irrigation and crop rotation were not accounted for by the CASA model. When managed and disturbed locations are removed from the validation, the R2 increases to 0.82. Conclusions The revised CASA model with pure-pixel interpolated vegetation index performed well at tower sites where vegetation was not manipulated or managed and had not been recently disturbed. Tower locations that showed relatively low correlations with CASA-estimated NPP were regularly disturbed by either human or natural forces.

  6. Net community production and calcification from 7 years of NOAA Station Papa Mooring measurements

    Science.gov (United States)

    Fassbender, Andrea J.; Sabine, Christopher L.; Cronin, Meghan F.

    2016-02-01

    Seven years of near-continuous observations from the Ocean Station Papa (OSP) surface mooring were used to evaluate drivers of marine carbon cycling in the eastern subarctic Pacific. Processes contributing to mixed layer carbon inventory changes throughout each deployment year were quantitatively assessed using a time-dependent mass balance approach in which total alkalinity and dissolved inorganic carbon were used as tracers. By using two mixed layer carbon tracers, it was possible to isolate the influences of net community production (NCP) and calcification. Our results indicate that the annual NCP at OSP is 2 ± 1 mol C m-2 yr-1 and the annual calcification is 0.3 ± 0.3 mol C m-2 yr-1. Piecing together evidence for potentially significant dissolved organic carbon cycling in this region, we estimate a particulate inorganic carbon to particulate organic carbon ratio between 0.15 and 0.25. This is at least double the global average, adding to the growing evidence that calcifying organisms play an important role in carbon export at this location. These results, coupled with significant seasonality in the NCP, suggest that carbon cycling near OSP may be more complex than previously thought and highlight the importance of continuous observations for robust assessments of biogeochemical cycling.

  7. Greenhouse Gas Emissions from Agricultural Production

    DEFF Research Database (Denmark)

    Bennetzen, Eskild Hohlmann

    . The KPI enables combined analyses of changes in total emissions, emissions per area and emissions per product. Also, the KPI can be used to assess how a change in each GHG emission category affects the change in total emissions; thus pointing to where things are going well and where things are going less......-production, respectively. Only emissions from energy use have increased more than production. Our projected BAU scenarios suggest that emissions may be further decoupled by 20 – 55% giving absolute agricultural emissions in the range of 8.2 to 14.5 Pg CO2-eq. yr-1 by 2050; lower than most other suggest from estimates...... that do not allow for decoupling. In Paper III agricultural production and GHG emissions since 1970, are analysed for nine world regions. Decoupling of emissions from production shows vast regional differences. In general, the more developed regions show the lowest emissions per unit of agricultural...

  8. Seasonal distribution of dissolved inorganic carbon and net community production on the Bering Sea shelf

    Directory of Open Access Journals (Sweden)

    J. T. Mathis

    2010-05-01

    Full Text Available In order to assess the current state of net community production (NCP in the southeastern Bering Sea, we measured the spatio-temporal distribution and controls on dissolved inorganic carbon (DIC concentrations in spring and summer of 2008 across six shelf domains defined by differing biogeochemical characteristics. DIC concentrations were tightly coupled to salinity in spring and ranged from ~1900 μmoles kg−1 over the inner shelf to ~2400 μmoles kg−1 in the deeper waters of the Bering Sea. In summer, DIC concentrations were lower due to dilution from sea ice melt, terrestrial inputs, and primary production. Concentrations were found to be as low ~1800 μmoles kg−1 over the inner shelf. We found that DIC concentrations were drawn down 30–150 μmoles kg−1 in the upper 30 m of the water column due to primary production and calcium carbonate formation between the spring and summer occupations. Using the seasonal drawdown of DIC, estimated rates of NCP on the inner, middle, and outer shelf averaged 28 ± 9 mmoles C m−2 d−1. However, higher rates of NCP (40–47 mmoles C m−2 d−1 were observed in the "Green Belt" where the greatest confluence of nutrient-rich basin water and iron-rich shelf water occurs. We estimated that in 2008, total NCP across the shelf was on the order of ~96 Tg C yr−1. Due to the paucity of consistent, comparable productivity data, it is impossible at this time to quantify whether the system is becoming more or less productive. However, as changing climate continues to modify the character of the Bering Sea, we have shown that NCP can be an important indicator of how the ecosystem is functioning.

  9. Assessing sulfate and carbon controls on net methylmercury production in peatlands: An in situ mesocosm approach

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Carl P.J. [Department of Geography, University of Toronto at Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6 (Canada)], E-mail: mitchellc@si.edu; Branfireun, Brian A. [Department of Geography, University of Toronto at Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6 (Canada); Kolka, Randall K. [Northern Research Station, US Department of Agriculture Forest Service, 1831 Highway 169 East, Grand Rapids, MN 55744 (United States)

    2008-03-15

    The transformation of atmospherically deposited inorganic Hg to the toxic, organic form methylmercury (MeHg) is of serious ecological concern because MeHg accumulates in aquatic biota, including fish. Research has shown that the Hg methylation reaction is dependent on the availability of SO{sub 4} (as an electron acceptor) because SO{sub 4}-reducing bacteria (SRB) mediate the biotic methylation of Hg. Much less research has investigated the possible organic C limitations to Hg methylation (i.e. from the perspective of the electron donor). Although peatlands are long-term stores of organic C, the C derived from peatland vegetation is of questionable microbial lability. This research investigated how both SO{sub 4} and organic C control net MeHg production using a controlled factorial addition design in 44 in situ peatland mesocosms. Two levels of SO{sub 4} addition and energetic-equivalent additions (i.e. same number of electrons) of a number of organic C sources were used including glucose, acetate, lactate, coniferous litter leachate, and deciduous litter leachate. This study supports previous research demonstrating the stimulation of MeHg production from SO{sub 4} input alone ({approx}200 pg/L/day). None of the additions of organic C alone resulted in significant MeHg production. The combined addition of SO{sub 4} and some organic C sources resulted in considerably more MeHg production ({approx}500 pg/L/day) than did the addition of SO{sub 4} alone, demonstrating that the highest levels of MeHg production can be expected only where fluxes of both SO{sub 4} and organic C are delivered concurrently. When compared to a number of pore water samples taken from two nearby peatlands, MeHg concentrations resulting from the combined addition of SO{sub 4} and organic C in this study were similar to MeHg 'hot spots' found near the upland-peatland interface. The formation of MeHg 'hot spots' at the upland-peatland interface may be dependent on concurrent

  10. Valorization of Flue Gas by Combining Photocatalytic Gas Pretreatment with Microalgae Production.

    Science.gov (United States)

    Eynde, Erik Van; Lenaerts, Britt; Tytgat, Tom; Blust, Ronny; Lenaerts, Silvia

    2016-03-01

    Utilization of flue gas for algae cultivation seems to be a promising route because flue gas from fossil-fuel combustion processes contains the high amounts of carbon (CO2) and nitrogen (NO) that are required for algae growth. NO is a poor nitrogen source for algae cultivation because of its low reactivity and solublilty in water and its toxicity for algae at high concentrations. Here, we present a novel strategy to valorize NO from flue gas as feedstock for algae production by combining a photocatalytic gas pretreatment unit with a microalgal photobioreactor. The photocatalytic air pretreatment transforms NO gas into NO2 gas and thereby enhances the absorption of NOx in the cultivation broth. The absorbed NOx will form NO2(-) and NO3(-) that can be used as a nitrogen source by algae. The effect of photocatalytic air pretreatment on the growth and biomass productivity of the algae Thalassiosira weissflogii in a semicontinuous system aerated with a model flue gas (1% CO2 and 50 ppm of NO) is investigated during a long-term experiment. The integrated system makes it possible to produce algae with NO from flue gas as the sole nitrogen source and reduces the NOx content in the exhaust gas by 84%.

  11. A Timed Colored Petri Net Simulation-Based Self-Adaptive Collaboration Method for Production-Logistics Systems

    Directory of Open Access Journals (Sweden)

    Zhengang Guo

    2017-03-01

    Full Text Available Complex and customized manufacturing requires a high level of collaboration between production and logistics in a flexible production system. With the widespread use of Internet of Things technology in manufacturing, a great amount of real-time and multi-source manufacturing data and logistics data is created, that can be used to perform production-logistics collaboration. To solve the aforementioned problems, this paper proposes a timed colored Petri net simulation-based self-adaptive collaboration method for Internet of Things-enabled production-logistics systems. The method combines the schedule of token sequences in the timed colored Petri net with real-time status of key production and logistics equipment. The key equipment is made ‘smart’ to actively publish or request logistics tasks. An integrated framework based on a cloud service platform is introduced to provide the basis for self-adaptive collaboration of production-logistics systems. A simulation experiment is conducted by using colored Petri nets (CPN Tools to validate the performance and applicability of the proposed method. Computational experiments demonstrate that the proposed method outperforms the event-driven method in terms of reductions of waiting time, makespan, and electricity consumption. This proposed method is also applicable to other manufacturing systems to implement production-logistics collaboration.

  12. Net ecosystem production in a Little Ice Age moraine: the role of plant functional traits

    Science.gov (United States)

    Varolo, E.; Zanotelli, D.; Tagliavini, M.; Zerbe, S.; Montagnani, L.

    2015-07-01

    Current glacier retreat allows vast mountain ranges available for vegetation establishment and growth. Little is known about the effective carbon (C) budget of these new ecosystems and how the presence of different vegetation communities, characterized by their specific physiology and life forms influences C fluxes. In this study, using a comparative analysis of the C fluxes of two contrasting vegetation types, we intend to evaluate if the different physiologies of the main species have an effect on Ecosystem Respiration (Reco), Gross Primary Production (GPP), annual cumulated Net Ecosystem Exchange (NEE), and long-term carbon accumulation in soil. The NEE of two plant communities present on a Little Ice Age moraine in the Matsch glacier forefield (Alps, Italy) was measured over two growing seasons. They are a typical C3 grassland, dominated by Festuca halleri All. and a community dominated by CAM rosettes Sempervivum montanum L. on rocky soils. Using transparent and opaque chambers, we extrapolated the ecophysiological responses to the main environmental drivers and performed the partition of NEE into Reco and GPP. Soil samples were collected from the same site to measure long-term C accumulation in the ecosystem. The two communities showed contrasting GPP but similar Reco patterns and as a result significantly different in NEE. The grassland acted mainly as a carbon sink with a total cumulated value of -46.4 ± 35.5 g C m-2 NEE while the plots dominated by the CAM rosettes acted as a source with 31.9 ± 22.4 g C m-2. In spite of the NEE being different in the two plant communities, soil analysis did not reveal significant differences in carbon accumulation. Grasslands showed 1.76 ± 0.12 kg C m-2, while CAM rosettes showed 2.06 ± 0.23 kg C m-2. This study demonstrates that carbon dynamics of two vegetation communities can be distinct even though the growing environment is similar. The physiological traits of the dominant species determine large differences in

  13. Net energy production and emissions mitigation of domestic wastewater treatment system: a comparison of different biogas-sludge use alternatives.

    Science.gov (United States)

    Chen, Shaoqing; Chen, Bin

    2013-09-01

    Wastewater treatment systems are increasingly designed for the recovery of valuable chemicals and energy in addition to waste stream disposal. Herein, the life-cycle energy production and emissions mitigation of a typical domestic wastewater treatment system were assessed, in which different combinations of biogas use and sludge processing lines for industrial or household applications were considered. The results suggested that the reuse of biogas and sludge was so important in the system's overall energy balance and environmental performance that it may offset the cost in the plant's installation and operation. Combined heat and power and household utilization were two prior options for net energy production, provided an ideal power conversion efficiency and biogas production. The joint application of household biogas use and sludge nutrient processing achieved both high net energy production and significant environmental remediation across all impact categories, representing the optimal tradeoff for domestic wastewater treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Greenhouse gas mitigation in animal production

    DEFF Research Database (Denmark)

    De Boer, IJM; Cederberg, C; Eady, S

    2011-01-01

    . They did not account for the complex interrelated effects on other GHGs or their relation with other aspects of sustainability, such as eutrophication, animal welfare, land use or food security. Current decisions on GHG mitigation in animal production, therefore, are hindered by the complexity......The animal food chain contributes significantly to emission of greenhouse gases (GHGs). We explored studies that addressed options to mitigate GHG emissions in the animal production chain and concluded that most studies focused on production systems in developed countries and on a single GHG...

  15. Predicting global oceanic net primary productivity with reduced-dimension, linear dynamical spatiotemporal models

    Science.gov (United States)

    Gonzalez, F.; Barton, A.; Stock, C. A.

    2016-02-01

    Oceanic net primary production (NPP) accounts for roughly half of biological carbon fixation at the global scale, determining upper bounds for fisheries and export production. Assessing our ability to predict changes in NPP has thus major implications for the analysis of climate change impacts and for the management of living marine resources. Here, we fitted a series of reduced-dimension, linear dynamical spatiotemporal models to estimates of NPP derived from 18 years of remote sensing data and from simulations of a fully coupled, ocean-atmosphere Earth System Model (ESM). The method projects the evolution of NPP anomalies at the global scale from the time decay and interactions among a reduced set of major NPP modes of variability. This approach allowed us to assess potential limits to the predictability of NPP at the seasonal scale, and to assess the agreement in regional patterns of predictability based on remote sensing and ESM NPP estimates at large scales. The models are able to anticipate changes in NPP at lead times up to 24 months, especially in subtropical latitudes. Predictability was dominated by the decay of major modes at short time scales, with a prevalence of slow moving modes related to El Niño-Southern Oscillation and the Atlantic Multidecadal Oscillation. This decay dominated short-term predictions in both remote sensing and ESM NPP, although the modes prevailed for a longer time in ESM simulations. The dominance of short time persistence declined gradually at longer lead times as interactions between modes became more important for predicting NPP changes. These interactions were related to the propagation of major climate modes. Our approach provides a novel set of diagnostics to assess the performance of ESMs, and allowed us to identify potential regions where the prediction of NPP might lead to an improved management of living marine resources.

  16. Controls of vegetation structure and net primary production in restored grasslands

    Science.gov (United States)

    Munson, Seth M.; Lauenroth, William K.

    2014-01-01

    1. Vegetation structure and net primary production (NPP) are fundamental properties of ecosystems. Understanding how restoration practices following disturbance interact with environmental factors to control these properties can provide insight on how ecosystems recover and guide management efforts. 2. We assessed the relative contribution of environmental and restoration factors in controlling vegetation structure, above- and below-ground investment in production across a chronosequence of semiarid Conservation Reserve Program (CRP) fields recovering from dryland wheat cropping relative to undisturbed grassland. Importantly, we determined the role of plant diversity and how seeding either native or introduced perennial grasses influenced the recovery of vegetation properties. 3. Plant basal cover increased with field age and was highest in CRP fields seeded with native perennial grasses. In contrast, fields seeded with introduced perennial grasses had tall-growing plants with relatively low basal cover. These vegetation structural characteristics interacted with precipitation, but not soil characteristics, to influence above-ground NPP (ANPP). Fields enrolled in the CRP program for >7 years supported twice as much ANPP as undisturbed shortgrass steppe in the first wet year of the study, but all CRP fields converged on a common low amount of ANPP in the following dry year and invested less than half as much as the shortgrass steppe in below-ground biomass. 4. ANPP in CRP fields seeded with native perennial grasses for more than 7 years was positively related to species richness, whereas ANPP in CRP fields seeded with introduced perennial grasses were controlled more by dominant species. 5. Synthesis and applications. Seeding with introduced, instead of native, perennial grasses had a strong direct influence on vegetation structure, including species richness, which indirectly affected NPP through time. However, the effects of restoring either native or introduced

  17. Green Net Regional Product for the San Luis Basin, Colorado: an economic measure of regional sustainability.

    Science.gov (United States)

    Heberling, Matthew T; Templeton, Joshua J; Wu, Shanshan

    2012-11-30

    This paper presents the data sources and methodology used to estimate Green Net Regional Product (GNRP), a green accounting approach, for the San Luis Basin (SLB). We measured the movement away from sustainability by examining the change in GNRP over time. Any attempt at green accounting requires both economic and natural capital data. However, limited data for the Basin requires a number of simplifying assumptions and requires transforming economic data at the national, state, and county levels to the level of the SLB. Given the contribution of agribusiness to the SLB, we included the depletion of both groundwater and soil as components in the depreciation of natural capital. We also captured the effect of the consumption of energy on climate change for future generations through carbon dioxide (CO(2)) emissions. In order to estimate the depreciation of natural capital, the shadow price of water for agriculture, the economic damages from soil erosion due to wind, and the social cost of carbon emissions were obtained from the literature and applied to the SLB using benefit transfer. We used Colorado's total factor productivity for agriculture to estimate the value of time (i.e., to include the effects of exogenous technological progress). We aggregated the economic data and the depreciation of natural capital for the SLB from 1980 to 2005. The results suggest that GNRP had a slight upward trend through most of this time period, despite temporary negative trends, the longest of which occurred during the period 1985-86 to 1987-88. However, given the upward trend in GNRP and the possibility of business cycles causing the temporary declines, there is no definitive evidence of moving away from sustainability. Published by Elsevier Ltd.

  18. Estimation of net primary productivity using a process-based model in Gansu Province, Northwest China

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peijuan; Xie, Donghui; Zhou, Yuyu; E, Youhao; Zhu, Qijiang

    2014-01-16

    The ecological structure in the arid and semi-arid region of Northwest China with forest, grassland, agriculture, Gobi, and desert, is complex, vulnerable, and unstable. It is a challenging and sustaining job to keep the ecological structure and improve its ecological function. Net primary productivity (NPP) modeling can help to improve the understanding of the ecosystem, and therefore, improve ecological efficiency. The boreal ecosystem productivity simulator (BEPS) model provides the possibility of NPP modeling in terrestrial ecosystem, but it has some limitations for application in arid and semi-arid regions. In this paper we improve the BEPS model, in terms of its water cycle by adding the processes of infiltration and surface runoff, to be applicable in arid and semi-arid regions. We model the NPP of forest, grass, and crop in Gansu Province as an experimental area in Northwest China in 2003 using the improved BEPS model, parameterized with moderate resolution remote sensing imageries and meteorological data. The modeled NPP using improved BEPS agrees better with the ground measurements in Qilian Mountain than that with original BEPS, with a higher R2 of 0.746 and lower root mean square error (RMSE) of 46.53 gC/m2 compared to R2 of 0.662 and RMSE of 60.19 gC/m2 from original BEPS. The modeled NPP of three vegetation types using improved BEPS show evident differences compared to that using original BEPS, with the highest difference ratio of 9.21% in forest and the lowest value of 4.29% in crop. The difference ratios between different vegetation types lie on the dependence on natural water sources. The modeled NPP in five geographic zones using improved BEPS are higher than those with original BEPS, with higher difference ratio in dry zones and lower value in wet zones.

  19. Creating a Regional MODIS Satellite-Driven Net Primary Production Dataset for European Forests

    Directory of Open Access Journals (Sweden)

    Mathias Neumann

    2016-06-01

    Full Text Available Net primary production (NPP is an important ecological metric for studying forest ecosystems and their carbon sequestration, for assessing the potential supply of food or timber and quantifying the impacts of climate change on ecosystems. The global MODIS NPP dataset using the MOD17 algorithm provides valuable information for monitoring NPP at 1-km resolution. Since coarse-resolution global climate data are used, the global dataset may contain uncertainties for Europe. We used a 1-km daily gridded European climate data set with the MOD17 algorithm to create the regional NPP dataset MODIS EURO. For evaluation of this new dataset, we compare MODIS EURO with terrestrial driven NPP from analyzing and harmonizing forest inventory data (NFI from 196,434 plots in 12 European countries as well as the global MODIS NPP dataset for the years 2000 to 2012. Comparing these three NPP datasets, we found that the global MODIS NPP dataset differs from NFI NPP by 26%, while MODIS EURO only differs by 7%. MODIS EURO also agrees with NFI NPP across scales (from continental, regional to country and gradients (elevation, location, tree age, dominant species, etc.. The agreement is particularly good for elevation, dominant species or tree height. This suggests that using improved climate data allows the MOD17 algorithm to provide realistic NPP estimates for Europe. Local discrepancies between MODIS EURO and NFI NPP can be related to differences in stand density due to forest management and the national carbon estimation methods. With this study, we provide a consistent, temporally continuous and spatially explicit productivity dataset for the years 2000 to 2012 on a 1-km resolution, which can be used to assess climate change impacts on ecosystems or the potential biomass supply of the European forests for an increasing bio-based economy. MODIS EURO data are made freely available at ftp://palantir.boku.ac.at/Public/MODIS_EURO.

  20. Microalgae Production from Power Plant Flue Gas: Environmental Implications on a Life Cycle Basis

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, K. L.

    2001-06-22

    Power-plant flue gas can serve as a source of CO{sub 2} for microalgae cultivation, and the algae can be cofired with coal. This life cycle assessment (LCA) compared the environmental impacts of electricity production via coal firing versus coal/algae cofiring. The LCA results demonstrated lower net values for the algae cofiring scenario for the following using the direct injection process (in which the flue gas is directly transported to the algae ponds): SOx, NOx, particulates, carbon dioxide, methane, and fossil energy consumption. Carbon monoxide, hydrocarbons emissions were statistically unchanged. Lower values for the algae cofiring scenario, when compared to the burning scenario, were observed for greenhouse potential and air acidification potential. However, impact assessment for depletion of natural resources and eutrophication potential showed much higher values. This LCA gives us an overall picture of impacts across different environmental boundaries, and hence, can help in the decision-making process for implementation of the algae scenario.

  1. Continuous flow production of concentrated hyperpolarized xenon gas from a dilute xenon gas mixture by buffer gas condensation.

    Science.gov (United States)

    Imai, Hirohiko; Yoshimura, Hironobu; Kimura, Atsuomi; Fujiwara, Hideaki

    2017-08-04

    We present a new method for the continuous flow production of concentrated hyperpolarized xenon-129 (HP (129)Xe) gas from a dilute xenon (Xe) gas mixture with high nuclear spin polarization. A low vapor pressure (i.e., high boiling-point) gas was introduced as an alternative to molecular nitrogen (N2), which is the conventional quenching gas for generating HP (129)Xe via Rb-Xe spin-exchange optical-pumping (SEOP). In contrast to the generally used method of extraction by freezing Xe after the SEOP process, the quenching gas separated as a liquid at moderately low temperature so that Xe was maintained in its gaseous state, allowing the continuous delivery of highly polarized concentrated Xe gas. We selected isobutene as the candidate quenching gas and our method was demonstrated experimentally while comparing its performance with N2. Isobutene could be liquefied and removed from the Xe gas mixture using a cold trap, and the concentrated HP (129)Xe gas exhibited a significantly enhanced nuclear magnetic resonance (NMR) signal. Although the system requires further optimization depending on the intended purpose, our approach presented here could provide a simple means for performing NMR or magnetic resonance imaging (MRI) measurements continuously using HP (129)Xe with improved sensitivity.

  2. Climate impact of potential shale gas production in the EU

    Energy Technology Data Exchange (ETDEWEB)

    Forster, D.; Perks, J. [AEA Technology plc, London (United Kingdom)

    2012-07-15

    Existing estimates of GHG emissions from shale gas production and available abatement options were used to obtain improved estimates of emissions from possible shale gas exploitation in the EU. GHG emissions per unit of electricity generated from shale gas were estimated to be around 4 to 8% higher than for electricity generated by conventional pipeline gas from within Europe. These additional emissions arise in the pre-combustion stage, predominantly in the well completion phase when the fracturing fluid is brought back to the surface together with released methane. If emissions from well completion are mitigated, through flaring or capture, and utilised, then this difference is reduced to 1 to 5%. The analysis suggests that the emissions from shale gas-based power generation (base case) are 2 to 10% lower than those from electricity generated from sources of conventional pipeline gas located outside of Europe (in Russia and Algeria), and 7 to 10% lower than those from electricity generated from LNG imported into Europe. However, under our 'worst case' shale gas scenario, where all flow back gases at well completion are vented, emissions from electricity generated from shale gas would be similar to the upper emissions level for electricity generated from imported LNG and for gas imported from Russia.

  3. Investigation of Productivity of Brown’s (HHO Gas Generator

    Directory of Open Access Journals (Sweden)

    Andrius Brazdžiūnas

    2017-01-01

    Full Text Available There were made tests of productivity of Brown’s gas generator using different potassium hydroxide (KOH concentration changing voltage and amperage. It is described experimental stand that is used to do researches and methodology of experiments performance. Brown’s gas production in electrolyser (electrolyser – the device that is going electrolysis to use stainless steel (AISI 316 electrodes. It was determined after researches that increasing the potassium hydroxide (KOH concentration in the solution and using the same amperage and voltage of the all concentration results are similar. The highest productivity 1.429 l/min was obtained by using a 120 A amperage and 15 V voltage.

  4. Automation of Presentation Record Production Based on Rich-Media Technology Using SNT Petri Nets Theory

    Directory of Open Access Journals (Sweden)

    Ivo Martiník

    2015-01-01

    Full Text Available Rich-media describes a broad range of digital interactive media that is increasingly used in the Internet and also in the support of education. Last year, a special pilot audiovisual lecture room was built as a part of the MERLINGO (MEdia-rich Repository of LearnING Objects project solution. It contains all the elements of the modern lecture room determined for the implementation of presentation recordings based on the rich-media technologies and their publication online or on-demand featuring the access of all its elements in the automated mode including automatic editing. Property-preserving Petri net process algebras (PPPA were designed for the specification and verification of the Petri net processes. PPPA does not need to verify the composition of the Petri net processes because all their algebraic operators preserve the specified set of the properties. These original PPPA are significantly generalized for the newly introduced class of the SNT Petri process and agent nets in this paper. The PLACE-SUBST and ASYNC-PROC algebraic operators are defined for this class of Petri nets and their chosen properties are proved. The SNT Petri process and agent nets theory were significantly applied at the design, verification, and implementation of the programming system ensuring the pilot audiovisual lecture room functionality.

  5. Automation of Presentation Record Production Based on Rich-Media Technology Using SNT Petri Nets Theory.

    Science.gov (United States)

    Martiník, Ivo

    2015-01-01

    Rich-media describes a broad range of digital interactive media that is increasingly used in the Internet and also in the support of education. Last year, a special pilot audiovisual lecture room was built as a part of the MERLINGO (MEdia-rich Repository of LearnING Objects) project solution. It contains all the elements of the modern lecture room determined for the implementation of presentation recordings based on the rich-media technologies and their publication online or on-demand featuring the access of all its elements in the automated mode including automatic editing. Property-preserving Petri net process algebras (PPPA) were designed for the specification and verification of the Petri net processes. PPPA does not need to verify the composition of the Petri net processes because all their algebraic operators preserve the specified set of the properties. These original PPPA are significantly generalized for the newly introduced class of the SNT Petri process and agent nets in this paper. The PLACE-SUBST and ASYNC-PROC algebraic operators are defined for this class of Petri nets and their chosen properties are proved. The SNT Petri process and agent nets theory were significantly applied at the design, verification, and implementation of the programming system ensuring the pilot audiovisual lecture room functionality.

  6. Ice melt influence on summertime net community production along the Western Antarctic Peninsula

    Science.gov (United States)

    Eveleth, R.; Cassar, N.; Sherrell, R. M.; Ducklow, H.; Meredith, M. P.; Venables, H. J.; Lin, Y.; Li, Z.

    2017-05-01

    The Western Antarctic Peninsula (WAP) is a highly productive marine environment that is undergoing rapid change, with consequences for productivity and total ecosystem carbon cycling. We present continuous underway O2/Ar estimates of net community production (NCPO2Ar) in austral summer 2012, 2013 and 2014 at sub-kilometer horizontal resolution within the Palmer Long-Term Ecological Research (Pal-LTER) grid region of the WAP. Substantial spatial variability is observed with NCPO2Ar ranging from 0 to 790 mmol O2 m-2 d-1 and considerable interannual variability with mean values in the grid region of 54.4±48.5, 44.6±40.5, and 85.6±75.9 mmol O2 m-2 d-1 in 2012, 2013 and 2014 respectively. Based on a strong correlation (r2=0.83) between residence time integrated NCPO2Ar and NCPDIC derived from seasonal DIC drawdown, we find the observed NCPO2Ar spatial and interannual variability to be consistent with the December-January NCPDIC magnitude. Seeking to explain the mechanistic drivers of NCP in the WAP, we observe a linear relationship between NCPO2Ar and meteoric water content derived from δ18O and salinity. This correlation may be due to Fe supply from glacial melt and/or strengthening of stratification and relief of light limitation. Elevated surface Fe availability, as indicated by Fv/Fm and measurements of surface water dissolved Fe and Mn (a rough proxy for recent potential Fe availability), and shallower, more stable mixed layers are present where meteoric water and/or sea ice melt is high near the coast. Light limitation is evident in the WAP when mixed layer depths are greater than 40 m. Additionally we document hotspots of NCP associated with submarine canyons along the WAP. While it is difficult to predict how the physical-biological system might evolve under changing climatic conditions, it is evident that NCP, and potentially carbon flux out of the mixed layer, along the WAP will be sensitive to shifts in meltwater input and timing.

  7. Emissions implications of future natural gas production and use in the U.S. and in the Rocky Mountain region.

    Science.gov (United States)

    McLeod, Jeffrey D; Brinkman, Gregory L; Milford, Jana B

    2014-11-18

    Enhanced prospects for natural gas production raise questions about the balance of impacts on air quality, as increased emissions from production activities are considered alongside the reductions expected when natural gas is burned in place of other fossil fuels. This study explores how trends in natural gas production over the coming decades might affect emissions of greenhouse gases (GHG), volatile organic compounds (VOCs) and nitrogen oxides (NOx) for the United States and its Rocky Mountain region. The MARKAL (MARKet ALlocation) energy system optimization model is used with the U.S. Environmental Protection Agency's nine-region database to compare scenarios for natural gas supply and demand, constraints on the electricity generation mix, and GHG emissions fees. Through 2050, total energy system GHG emissions show little response to natural gas supply assumptions, due to offsetting changes across sectors. Policy-driven constraints or emissions fees are needed to achieve net reductions. In most scenarios, wind is a less expensive source of new electricity supplies in the Rocky Mountain region than natural gas. U.S. NOx emissions decline in all the scenarios considered. Increased VOC emissions from natural gas production offset part of the anticipated reductions from the transportation sector, especially in the Rocky Mountain region.

  8. Gas Fermentation using Thermophilic Moorella Species for production of Biochemicals

    DEFF Research Database (Denmark)

    Redl, Stephanie Maria Anna

    Gas fermentation is a promising technology which gained increasing attention over the last years. In this process, acetogenic bacteria convert gases rich in H2, CO2, and CO, into compounds of higher value. The gas can derive from industrial off-gas or from waste streams via gasification. In the gas...... with a review of the feedstock potential for gas fermentation and how thermophilic production strains as well as unconventional fermentation processes such as mixotrophy can help to exploit this potential. I analyzed a process with respect to thermodynamic and economic considerations, in which acetone...... with collaborators, I identified M. thermoautotrophica to be a mixed culture of M. thermoacetica strains. We de novo sequenced the genome of several M. thermoacetica strains to shed light on the taxonomic relations within the genus Moorella. Although well studied, some aspects of the physiology of M. thermoacetica...

  9. Prediction of the Export and Fate of Global Ocean Net Primary Production: The EXPORTS Science Plan

    Directory of Open Access Journals (Sweden)

    David A Siegel

    2016-03-01

    Full Text Available Ocean ecosystems play a critical role in the Earth’s carbon cycle and the quantification of their impacts for both present conditions and for predictions into the future remains one of the greatest challenges in oceanography. The goal of the EXport Processes in the Ocean from Remote Sensing (EXPORTS Science Plan is to develop a predictive understanding of the export and fate of global ocean net primary production (NPP and its implications for present and future climates. The achievement of this goal requires a quantification of the mechanisms that control the export of carbon from the euphotic zone as well as its fate in the underlying twilight zone where some fraction of exported carbon will be sequestered in the ocean’s interior on time scales of months to millennia. Here we present a measurement / synthesis / modeling framework aimed at quantifying the fates of upper ocean NPP and its impacts on the global carbon cycle based upon the EXPORTS Science Plan. The proposed approach will diagnose relationships among the ecological, biogeochemical and physical oceanographic processes that control carbon cycling across a range of ecosystem and carbon cycling states leading to advances in satellite diagnostic and numerical prognostic models. To collect these data, a combination of ship and robotic field sampling, satellite remote sensing and numerical modeling is proposed which enables the sampling of the many pathways of NPP export and fates. This coordinated, process-oriented approach has the potential to foster new insights on ocean carbon cycling that maximizes its societal relevance through the achievement of research goals of many international research agencies and will be a key step towards our understanding of the Earth as an integrated system.

  10. A new framework for evaluating the impacts of drought on net primary productivity of grassland.

    Science.gov (United States)

    Lei, Tianjie; Wu, Jianjun; Li, Xiaohan; Geng, Guangpo; Shao, Changliang; Zhou, Hongkui; Wang, Qianfeng; Liu, Leizhen

    2015-12-01

    This paper presented a valuable framework for evaluating the impacts of droughts (single factor) on grassland ecosystems. This framework was defined as the quantitative magnitude of drought impact that unacceptable short-term and long-term effects on ecosystems may experience relative to the reference standard. Long-term effects on ecosystems may occur relative to the reference standard. Net primary productivity (NPP) was selected as the response indicator of drought to assess the quantitative impact of drought on Inner Mongolia grassland based on the Standardized Precipitation Index (SPI) and BIOME-BGC model. The framework consists of six main steps: 1) clearly defining drought scenarios, such as moderate, severe and extreme drought; 2) selecting an appropriate indicator of drought impact; 3) selecting an appropriate ecosystem model and verifying its capabilities, calibrating the bias and assessing the uncertainty; 4) assigning a level of unacceptable impact of drought on the indicator; 5) determining the response of the indicator to drought and normal weather state under global-change; and 6) investigating the unacceptable impact of drought at different spatial scales. We found NPP losses assessed using the new framework were more sensitive to drought and had higher precision than the long-term average method. Moreover, the total and average losses of NPP are different in different grassland types during the drought years from 1961-2009. NPP loss was significantly increased along a gradient of increasing drought levels. Meanwhile, NPP loss variation under the same drought level was different in different grassland types. The operational framework was particularly suited for integrative assessing the effects of different drought events and long-term droughts at multiple spatial scales, which provided essential insights for sciences and societies that must develop coping strategies for ecosystems for such events. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Assessing the impacts of droughts on net primary productivity in China.

    Science.gov (United States)

    Pei, Fengsong; Li, Xia; Liu, Xiaoping; Lao, Chunhua

    2013-01-15

    Frequency and severity of droughts were projected to increase in many regions. However, their effects of temporal dynamics on the terrestrial carbon cycle remain uncertain, and hence deserve further investigation. In this paper, the droughts that occurred in China during 2001-2010 were identified by using the standardized precipitation index (SPI). Standardized anomaly index (SAI), which has been widely employed in reflecting precipitation, was extended to evaluate the anomalies of net primary productivity (NPP). In addition, influences of the droughts on vegetation were explored by examining the temporal dynamics of SAI-NPP along with area-weighted drought intensity at different time scales (1, 3, 6, 9 and 12 months). Year-to-year variability of NPP with several factors, including droughts, NDVI, radiation and temperature, was analyzed as well. Consequently, the droughts in the years 2001, 2006 and 2009 were well reconstructed. This indicates that SPI could be applied to the monitoring of the droughts in China during the past decade (2001-2010) effectively. Moreover, strongest correlations between droughts and NPP anomalies were found during or after the drought intensities reached their peak values. In addition, some droughts substantially reduced the countrywide NPP, whereas the others did not. These phenomena can be explained by the regional diversities of drought intensity, drought duration, areal extents of the droughts, as well as the cumulative and lag responses of vegetation to the precipitation deficits. Besides the drought conditions, normalized difference vegetation index (NDVI), radiation and temperature also contribute to the interannual variability of NPP. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Effects of UVB radiation on net community production in the upper global ocean

    KAUST Repository

    Garcia-Corral, Lara S.

    2016-08-31

    Aim Erosion of the stratospheric ozone layer together with oligotrophication of the subtropical ocean is leading to enhanced exposure to ultraviolet B (UVB) radiation in ocean surface waters. The impact of increased exposure to UVB on planktonic primary producers and heterotrophs is uncertain. Here we test the null hypothesis that net community production (NCP) of plankton communities in surface waters of the tropical and subtropical ocean is not affected by ambient UVB radiation and extend this test to the global ocean, including the polar oceans and the Mediterranean Sea using previous results. Location We conducted experiments with 131 surface communities sampled during a circumnavigation cruise along the tropical and subtropical ocean and combined these results with 89 previous reports encompassing the Atlantic, Pacific, Arctic and Southern Oceans and the Mediterranean Sea. Methods The use of quartz (transparent to UVB radiation) and borosilicate glass materials (opaque to most UVB) for incubations allowed us to compare NCP between communities where UVB is excluded and those receiving natural UVB radiation. Results We found that NCP varies when exposed to natural UVB radiation compared to those where UVB was removed. NCP of autotrophic communities tended to decrease under natural UVB radiation, whereas the NCP of heterotrophic communities tended to increase. However, these variations showed the opposite trend under higher levels of UVB radiation. Main conclusions Our results suggest that earlier estimates of NCP for surface communities, which were hitherto derived using materials blocking UVB radiation were biased, with the direction and magnitude of this bias depending on the metabolic status of the communities and the underwater penetration of UVB radiation.

  13. Relationships between net primary productivity and forest stand age in U.S. forests

    Science.gov (United States)

    He, Liming; Chen, Jing M.; Pan, Yude; Birdsey, Richard; Kattge, Jens

    2012-09-01

    Net primary productivity (NPP) is a key flux in the terrestrial ecosystem carbon balance, as it summarizes the autotrophic input into the system. Forest NPP varies predictably with stand age, and quantitative information on the NPP-age relationship for different regions and forest types is therefore fundamentally important for forest carbon cycle modeling. We used four terms to calculate NPP: annual accumulation of live biomass, annual mortality of aboveground and belowground biomass, foliage turnover to soil, and fine root turnover in soil. For U.S. forests the first two terms can be reliably estimated from the Forest Inventory and Analysis (FIA) data. Although the last two terms make up more than 50% of total NPP, direct estimates of these fluxes are highly uncertain due to limited availability of empirical relationships between aboveground biomass and foliage or fine root biomass. To resolve this problem, we developed a new approach using maps of leaf area index (LAI) and forest age at 1 km resolution to derive LAI-age relationships for 18 major forest type groups in the USA. These relationships were then used to derive foliage turnover estimates using species-specific trait data for leaf specific area and longevity. These turnover estimates were also used to derive the fine root turnover based on reliable relationships between fine root and foliage turnover. This combination of FIA data, remote sensing, and plant trait information allows for the first empirical and reliable NPP-age relationships for different forest types in the USA. The relationships show a general temporal pattern of rapid increase in NPP in the young ages of forest type groups, peak growth in the middle ages, and slow decline in the mature ages. The predicted patterns are influenced by climate conditions and can be affected by forest management. These relationships were further generalized to three major forest biomes for use by continental-scale carbon cycle models in conjunction with

  14. Knowledge based decision making: perspective on natural gas production

    Energy Technology Data Exchange (ETDEWEB)

    Ydstie, B. Erik; Stuland, Kjetil M.

    2009-07-01

    Conclusions (drawn by the author): Decarbonization of energy sources - From coal to renewable. Natural Gas Abundantly available - Norway is no. 3 exporter. Natural gas important as - Hydrogen source for chemicals; - Electricity; - End consumer usage (heating etc). Large potential for application of model based decision making; - Where and when to install platforms and drill wells - How to operate platforms and pipeline systems; - How to operate and optimize chemical production; - Optimization of electricity generation systems. (author)

  15. Engineering analysis of biomass gasifier product gas cleaning technology

    Energy Technology Data Exchange (ETDEWEB)

    Baker, E.G.; Brown, M.D.; Moore, R.H.; Mudge, L.K.; Elliott, D.C.

    1986-08-01

    For biomass gasification to make a significant contribution to the energy picture in the next decade, emphasis must be placed on the generation of clean, pollutant-free gas products. This reports attempts to quantify levels of particulated, tars, oils, and various other pollutants generated by biomass gasifiers of all types. End uses for biomass gases and appropriate gas cleaning technologies are examined. Complete systems analysis is used to predit the performance of various gasifier/gas cleanup/end use combinations. Further research needs are identified. 128 refs., 20 figs., 19 tabs.

  16. Influence of biogenic gas production on coalbed methane recovery index

    Directory of Open Access Journals (Sweden)

    Hongyu Guo

    2017-05-01

    Full Text Available In investigating the effect of biogenic gas production on the recovery of coalbed methane (CBM, coal samples spanning different ranks were applied in the microbial-functioned simulation experiments for biogenic methane production. Based on the biogenic methane yield, testing of pore structures, and the isothermal adsorption data of coals used before and after the simulation experiments, several key parameters related to the recovery of CBM, including recovery rate, gas saturation and ratio of critical desorption pressure to reservoir pressure, etc., were calculated and the corresponding variations were further analyzed. The results show that one of the significant functions of microbial communities on coal is possibly to weaken its affinity for methane gas, especially with the advance of coal ranks; and that by enhancing the pore system of coal, which can be evidenced by the increase of porosity and permeability, the samples collected from Qianqiu (Yima in Henan and Shaqu (Liulin in Shanxi coal mines all see a notable increase in the critical desorption pressure, gas saturation and recovery rate, as compared to the moderate changes of that of Guandi (Xishan in Shanxi coal sample. It is concluded that the significance of enhanced biogenic gas is not only in the increase of CBM resources and the improvement of CBM recoverability, but in serving as an engineering reference for domestic coalbed biogenic gas production.

  17. Compressed gas domestic aerosol valve design using high viscous product

    Directory of Open Access Journals (Sweden)

    A Nourian

    2016-10-01

    Full Text Available Most of the current universal consumer aerosol products using high viscous product such as cooking oil, antiperspirants, hair removal cream are primarily used LPG (Liquefied Petroleum Gas propellant which is unfriendly environmental. The advantages of the new innovative technology described in this paper are: i. No butane or other liquefied hydrocarbon gas is used as a propellant and it replaced with Compressed air, nitrogen or other safe gas propellant. ii. Customer acceptable spray quality and consistency during can lifetime iii. Conventional cans and filling technology There is only a feasible energy source which is inert gas (i.e. compressed air to replace VOCs (Volatile Organic Compounds and greenhouse gases, which must be avoided, to improve atomisation by generating gas bubbles and turbulence inside the atomiser insert and the actuator. This research concentrates on using "bubbly flow" in the valve stem, with injection of compressed gas into the passing flow, thus also generating turbulence. The new valve designed in this investigation using inert gases has advantageous over conventional valve with butane propellant using high viscous product (> 400 Cp because, when the valving arrangement is fully open, there are negligible energy losses as fluid passes through the valve from the interior of the container to the actuator insert. The use of valving arrangement thus permits all pressure drops to be controlled, resulting in improved control of atomising efficiency and flow rate, whereas in conventional valves a significant pressure drops occurs through the valve which has a complex effect on the corresponding spray.

  18. Future supply and demand of net primary production in the Sahel

    Science.gov (United States)

    Sallaba, Florian; Olin, Stefan; Engström, Kerstin; Abdi, Abdulhakim M.; Boke-Olén, Niklas; Lehsten, Veiko; Ardö, Jonas; Seaquist, Jonathan W.

    2017-12-01

    In the 21st century, climate change in combination with increasing demand, mainly from population growth, will exert greater pressure on the ecosystems of the Sahel to supply food and feed resources. The balance between supply and demand, defined as the annual biomass required for human consumption, serves as a key metric for quantifying basic resource shortfalls over broad regions.Here we apply an exploratory modelling framework to analyse the variations in the timing and geography of different NPP (net primary production) supply-demand scenarios, with distinct assumptions determining supply and demand, for the 21st century Sahel. We achieve this by coupling a simple NPP supply model forced with projections from four representative concentration pathways with a global, reduced-complexity demand model driven by socio-economic data and assumptions derived from five shared socio-economic pathways.For the scenario that deviates least from current socio-economic and climate trends, we find that per capita NPP begins to outstrip supply in the 2040s, while by 2050 half the countries in the Sahel experience NPP shortfalls. We also find that despite variations in the timing of the onset of NPP shortfalls, demand cannot consistently be met across the majority of scenarios. Moreover, large between-country variations are shown across the scenarios, in which by the year 2050 some countries consistently experience shortage or surplus, while others shift from surplus to shortage. At the local level (i.e. grid cell), hotspots of total NPP shortfall consistently occur in the same locations across all scenarios but vary in size and magnitude. These hotspots are linked to population density and high demand. For all scenarios, total simulated NPP supply doubles by 2050 but is outpaced by increasing demand due to a combination of population growth and the adoption of diets rich in animal products. Finally, variations in the timing of the onset and end of supply shortfalls stem from

  19. Effect of Glucagon on Net Splanchnic Cyclic AMP Production in Normal and Diabetic Men

    Science.gov (United States)

    Liljenquist, John E.; Bomboy, James D.; Lewis, Stephen B.; Sinclair-Smith, Bruce C.; Felts, Philip W.; Lacy, William W.; Crofford, Oscar B.; Liddle, Grant W.

    1974-01-01

    Glucagon activates hepatic adenylate cyclase, thereby increasing acutely the liver content of cyclic AMP (cAMP) as well as the release of cAMP into the hepatic vein. Insulin, on the other hand, antagonizes this glucagon-mediated cAMP production, thus providing a hypothetical mechanism through which insulin might correct some of the metabolic abnormalities of diabetes. To study this hormonal interaction in man, net splanchnic cAMP production (NScAMPP) was investigated in normal and insulin-dependent diabetic men under basal conditions and in response to intravenous glucagon, 50 ng/kg/min for 2 h. In normals (n=19), basal hepatic vein cAMP concentration was 23.6±1.1 nM and NScAMPP was 1.7±0.6 nmol/min. Glucagon stimulated NScAMPP in four normal subjects to a peak of 99.6±43 nmol/min at 25 min with a subsequent fall to 12.4±5.1 nmol/min by 90 min despite continuing glucagon infusion. Endogenous insulin secretion was stimulated as indicated by rising levels of immunoreactive insulin and C-peptide (connecting peptide) immunoreactivity, raising the possibility that endogenous insulin might be responsible for the fall in NScAMPP that followed the initial spike. In the diabetics (n=8), basal hepatic vein cAMP concentration was 24.7±1.2 nM and NScAMPP was undetectable. Glucagon stimulated NScAMPP in five diabetics to a peak of 169.9±42.6 with a subsequent fall to 17.4±3.9 nmol/min by 90 min even though endogenous insulin secretion was not stimulated (no rise in C-peptide immunoreactivity). Although the mean increase in NScAMPP was greater in the diabetics, the two groups did not differ significantly. Conclusions. In normal resting man the liver is a significant source of circulating cAMP. Diabetics do not release abnormally large amounts of hepatic cAMP under basal conditions. Glucagon markedly enhances hepatic cAMP release with a spike-decline pattern in both normal and diabetic men. The decline in hepatic cAMP release despite continuing glucagon stimulation is due

  20. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xi, E-mail: icy124@hotmail.com [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Toma, Yo [Faculty of Agriculture, Ehime University, 3-5-7, Tarumi, Matsuyama 790-8566, Ehime (Japan); Yeluripati, Jagadeesh [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland (United Kingdom); Iwasaki, Shinya [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Bellingrath-Kimura, Sonoko D. [Leibniz Centre for Agricultural Landscape Research, Institute of Land Use Systems (Germany); Jones, Edward O. [Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London (United Kingdom); Hatano, Ryusuke [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan)

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha{sup −1} yr{sup −1} in 1959–0.26 Mg C ha{sup −1} yr{sup −1} in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate

  1. Estimating Net Primary Production of Turfgrass in an Urban-Suburban Landscape with QuickBird Imagery

    Directory of Open Access Journals (Sweden)

    Jindong Wu

    2012-03-01

    Full Text Available Vegetation is a basic component of urban-suburban environments with significant area coverage. As a major vegetation type in US cities, urban turfgrass provides a range of important ecological services. This study examined the biological carbon fixation of turfgrass in a typical residential neighborhood by linking ground-based measurements, high resolution satellite remote sensing, and ecological modeling. The spatial distribution of turfgrass and its vegetative conditions were mapped with QuickBird satellite imagery. The significant amount of shadows existing in the imagery were detected and removed by taking advantage of the high radiometric resolution of the data. A remote sensing-driven production efficiency model was developed and parameterized with field biophysical measurements to estimate annual net primary production of turfgrass. The results indicated that turfgrass accounted for 38% of land cover in the study area. Turfgrass assimilated 0–1,301 g∙C∙m−2∙yr−1 depending on vegetative conditions and management intensity. The average annual net primary production per unit turfgrass cover by golf course grass (1,100.5 g∙C∙m−2 was much higher than that by regular lawn grass (771.2 g∙C∙m−2. However, lawn grass contributed more to the total net primary production than golf course grass due to its larger area coverage, although with higher spatial variability.

  2. Use of in vitro gas production technique to evaluate the effects of microwave irradiation on sorghum (Sorghum bicolor and wheat (Triticum sp. nutritive values and fermentation characteristics

    Directory of Open Access Journals (Sweden)

    Farhad Parnian

    2013-01-01

    Full Text Available Effects of microwave irradiation (900 W for 3, 5 and 7 min on the nutritive value of sorghum and wheat grains were evaluated by in vitro gas production technique. Gas volume was recorded at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h of incubation and kinetics of gas production were estimated using model: GP = A exp {– exp [1 + (be/A (LAG – t]}. Cumulative gas production at 24 h was used for estimation of metabolizable energy, net energy for lactation, short chain fatty acids, digestible organic matter and microbial protein. For sorghum grain, microwave irradiation increased cumulative gas production for most times of incubation linearly. Microwave treatments for 5 and 7 min increased the A fraction linearly in both cereal grain, whereas the maximum rate of gas production (b decreased linearly only in wheat grain. Microwave treatments for 3, 5 and 7 min increased (P<0.05 metabolizable energy, net energy for lactation and short chain fatty acids content of sorghum grain, but not of wheat grain. It was concluded that microwave irradiation changed the gas production parameters resulting changed ruminal fermentation characteristics that can be considered in ration formulation.

  3. Net primary productivity (NPP) and associated parameters for the U.S. outer continental shelf waters, 1998-2009 (NODC Accession 0071184)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession consists of monthly net primary productivity (NPP) estimates for 1998-2009 derived from the Vertically Generalized Production Model (VGPM) for the 26...

  4. Produced water management - clean and safe oil and gas production

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    The conference contains 22 presentations on topics within pollution sources and abatement, discharge reductions, water analysis and monitoring, water production, treatment and injection, enhanced recovery, condensate water, produced water markets, separation technologies for oil/gas/condensate and water, oil removal from solids, environmental risks of oil and gas production and environmental impacts on ecosystems and fisheries. Some oil field case histories are presented. The main focus is on the northern areas such as the North Sea, the north Atlantic Ocean and the Barents Sea, and technological aspects (tk)

  5. Consequences of agro-biofuel production for greenhouse gas emissions

    DEFF Research Database (Denmark)

    Carter, Mette Sustmann; Hauggaard-Nielsen, Henrik; Johansen, Anders

    2009-01-01

    associated with the use of nitrogen based fertilizers in agricultural production. Replacing fossil fuel-derived energy by biomass-derived energy is commonly and with increasing emphasis proposed as a mean to mitigate the CO2 emissions. However, a recent analysis of global emission data proposes...... as fertilizer for a maize energy crop within an organic cropping system. Furthermore, we assessed sustainability in terms of greenhouse gasses for co-production of bio-ethanol and bio-gas from maize. This was compared to estimated greenhouse gas balances for rye and grass-clover as alternative raw materials....

  6. A carbon budget for the Amundsen Sea Polynya, Antarctica: Estimating net community production and export in a highly productive polar ecosystem

    Directory of Open Access Journals (Sweden)

    PL Yager

    2016-12-01

    Full Text Available Abstract Polynyas, or recurring areas of seasonally open water surrounded by sea ice, are foci for energy and material transfer between the atmosphere and the polar ocean. They are also climate sensitive, with both sea ice extent and glacial melt influencing their productivity. The Amundsen Sea Polynya (ASP is the greenest polynya in the Southern Ocean, with summertime chlorophyll a concentrations exceeding 20 µg L−1. During the Amundsen Sea Polynya International Research Expedition (ASPIRE in austral summer 2010–11, we aimed to determine the fate of this high algal productivity. We collected water column profiles for total dissolved inorganic carbon (DIC and nutrients, particulate and dissolved organic matter, chlorophyll a, mesozooplankton, and microbial biomass to make a carbon budget for this ecosystem. We also measured primary and secondary production, community respiration rates, vertical particle flux and fecal pellet production and grazing. With observations arranged along a gradient of increasing integrated dissolved inorganic nitrogen drawdown (ΔDIN; 0.027–0.74 mol N m−2, changes in DIC in the upper water column (ranging from 0.2 to 4.7 mol C m−2 and gas exchange (0–1.7 mol C m−2 were combined to estimate early season net community production (sNCP; 0.2–5.9 mol C m−2 and then compared to organic matter inventories to estimate export. From a phytoplankton bloom dominated by Phaeocystis antarctica, a high fraction (up to ∼60% of sNCP was exported to sub-euphotic depths. Microbial respiration remineralized much of this export in the mid waters. Comparisons to short-term (2–3 days drifting traps and a year-long moored sediment trap capturing the downward flux confirmed that a relatively high fraction (3–6% of the export from ∼100 m made it through the mid waters to depth. We discuss the climate-sensitive nature of these carbon fluxes, in light of the changing sea ice cover and melting ice sheets in the region.

  7. Impact assessment of concentrate recirculation on the landfill gas production

    Directory of Open Access Journals (Sweden)

    Džolev Nikola M.

    2016-01-01

    Full Text Available This paper explores the impact of concentrate recirculation, as a product of leachate treated by reverse osmosis plant, on the production of landfill gas at the real-scale landfill for municipal solid waste. In an effort to come up with results experimental measurements were carried out at the landfill in Bijeljina. All measurements performed, were divided into 3 groups. The aims of two groups of measurement were to determine landfill gas and methane yield from concentrate and leachate in laboratory conditions (1st group and to find out concentrations of oxidizing matters (COD and BOD5 present in leachate and concentrate at different points of treatment as well as its variability over the time (2nd group which could be used to calculate the potential of landfill gas and methane generation from concentrate by recirculation, theoretically. 3rd group of measurements, carried out in parallel, have goal to determine the quality and quantity of the collected landfill gas at wells throughout the landfill. The results of analysis carried out in this experimental research show the clear evidence of concentrate recirculation impact on methane production by increasing the landfill gas flow, as well as its concentration within the landfill gas composition, at the nearby well. Although results indicated relatively high impact of concentrate recirculation on landfill gas production, comparing to its theoretical potential, the influence on the landfill at whole, is negligible, due to relatively low volumes in recirculation with respect to its size and objectively low potential given by organic matter present in concentrate.

  8. Drought dominates the interannual variability in global terrestrial net primary production by controlling semi-arid ecosystems

    OpenAIRE

    Ling Huang; Bin He; Aifang Chen; Haiyan Wang; Junjie Liu; Aifeng Lű; Ziyue Chen

    2016-01-01

    Drought is a main driver of interannual variation in global terrestrial net primary production. However, how and to what extent drought impacts global NPP variability is unclear. Based on the multi-timescale drought index SPEI and a satellite-based annual global terrestrial NPP dataset, we observed a robust relationship between drought and NPP in both hemispheres. In the Northern Hemisphere, the annual NPP trend is driven by 19-month drought variation, whereas that in the Southern Hemisphere ...

  9. Regenerative Gas Dryer for In-Situ Propellant Production

    Science.gov (United States)

    Paz, Aaron

    2017-01-01

    Rocket propellant can be produced anywhere that water is found by splitting it into hydrogen and oxygen, potentially saving several tons of mass per mission and enabling the long term presence of humans in space beyond LEO. When water is split into hydrogen and oxygen, the gaseous products can be very humid (several thousand ppm). Propellant-grade gases need to be extremely dry before being converted into cryogenic liquids (less than 26 ppm water for grade B Oxygen). The primary objective of this project is to design, build and test a regenerative gas drying system that can take humid gas from a water electrolysis system and provide dry gas (less than 26ppm water) to the inlet of a liquefaction system for long durations. State of the art work in this area attempted to use vacuum as a means to regenerate desiccant, but it was observed that water would migrate to the dry zone without a sweep gas present to direct the desorbed vapor. Further work attempted to use CO2 as a sweep gas, but this resulted in a corrosive carbonic acid. In order for in-situ propellant production to work, we need a way to continuously dry humid gas that addresses these issues.

  10. Natural gas production problems : solutions, methodologies, and modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Rautman, Christopher Arthur; Herrin, James M.; Cooper, Scott Patrick; Basinski, Paul M. (El Paso Production Company, Houston, TX); Olsson, William Arthur; Arnold, Bill Walter; Broadhead, Ronald F. (New Mexico Bureau of Geology and Mineral Resources, Socorro, NM); Knight, Connie D. (Consulting Geologist, Golden, CO); Keefe, Russell G.; McKinney, Curt (Devon Energy Corporation, Oklahoma City, OK); Holm, Gus (Vermejo Park Ranch, Raton, NM); Holland, John F.; Larson, Rich (Vermejo Park Ranch, Raton, NM); Engler, Thomas W. (New Mexico Institute of Mining and Technology, Socorro, NM); Lorenz, John Clay

    2004-10-01

    Natural gas is a clean fuel that will be the most important domestic energy resource for the first half the 21st centtuy. Ensuring a stable supply is essential for our national energy security. The research we have undertaken will maximize the extractable volume of gas while minimizing the environmental impact of surface disturbances associated with drilling and production. This report describes a methodology for comprehensive evaluation and modeling of the total gas system within a basin focusing on problematic horizontal fluid flow variability. This has been accomplished through extensive use of geophysical, core (rock sample) and outcrop data to interpret and predict directional flow and production trends. Side benefits include reduced environmental impact of drilling due to reduced number of required wells for resource extraction. These results have been accomplished through a cooperative and integrated systems approach involving industry, government, academia and a multi-organizational team within Sandia National Laboratories. Industry has provided essential in-kind support to this project in the forms of extensive core data, production data, maps, seismic data, production analyses, engineering studies, plus equipment and staff for obtaining geophysical data. This approach provides innovative ideas and technologies to bring new resources to market and to reduce the overall environmental impact of drilling. More importantly, the products of this research are not be location specific but can be extended to other areas of gas production throughout the Rocky Mountain area. Thus this project is designed to solve problems associated with natural gas production at developing sites, or at old sites under redevelopment.

  11. Production of hydrogen by thermocatalytic cracking of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Muradov, N.Z. [Univ. of Central Florida, Cape Canaveral, FL (United States)

    1995-09-01

    It is universally accepted that in the next few decades hydrogen production will continue to rely on fossil fuels (primarily, natural gas). On the other hand, the conventional methods of hydrogen production from natural gas (for example, steam reforming) are complex multi-step processes. These processes also result in the emission of large quantities of CO{sub 2} into the atmosphere that produce adverse ecological effects. One alternative is the one-step thermocatalytic cracking (TCC) (or decomposition) of natural gas into hydrogen and carbon. Preliminary analysis indicates that the cost of hydrogen produced by thermal decomposition of natural gas is somewhat lower than the conventional processes after by-product carbon credit is taken. In the short term, this process can be used for on-site production of hydrogen-methane mixtures in gas-filling stations and for CO{sub x}-free production of hydrogen for fuel cell driven prime movers. The experimental data on the thermocatalytic cracking of methane over various catalysts and supports in a wide range of temperatures (500-900{degrees}C) are presented in this paper. Two types of reactors were designed and built at FSEC: continuous flow and pulse fix bed catalytic reactors. The temperature dependence of the hydrogen production yield using oxide type catalysts was studied. Alumina-supported Ni- and Fe-catalysts demonstrated relatively high efficiency in the methane cracking reaction at moderate temperatures (600-800{degrees}C). Kinetic curves of hydrogen production over metal and metal oxide catalysts at different temperatures are presented in the paper. Fe-catalyst demonstrated good stability (for several hours), whereas alumina-supported Pt-catalyst rapidly lost its catalytic activity.

  12. Effects of vegetation heterogeneity and surface topography on spatial scaling of net primary productivity

    Science.gov (United States)

    Chen, J. M.; Chen, X.; Ju, W.

    2013-07-01

    Due to the heterogeneous nature of the land surface, spatial scaling is an inevitable issue in the development of land models coupled with low-resolution Earth system models (ESMs) for predicting land-atmosphere interactions and carbon-climate feedbacks. In this study, a simple spatial scaling algorithm is developed to correct errors in net primary productivity (NPP) estimates made at a coarse spatial resolution based on sub-pixel information of vegetation heterogeneity and surface topography. An eco-hydrological model BEPS-TerrainLab, which considers both vegetation and topographical effects on the vertical and lateral water flows and the carbon cycle, is used to simulate NPP at 30 m and 1 km resolutions for a 5700 km2 watershed with an elevation range from 518 m to 3767 m in the Qinling Mountain, Shanxi Province, China. Assuming that the NPP simulated at 30 m resolution represents the reality and that at 1 km resolution is subject to errors due to sub-pixel heterogeneity, a spatial scaling index (SSI) is developed to correct the coarse resolution NPP values pixel by pixel. The agreement between the NPP values at these two resolutions is improved considerably from R2 = 0.782 to R2 = 0.884 after the correction. The mean bias error (MBE) in NPP modelled at the 1 km resolution is reduced from 14.8 g C m-2 yr-1 to 4.8 g C m-2 yr-1 in comparison with NPP modelled at 30 m resolution, where the mean NPP is 668 g C m-2 yr-1. The range of spatial variations of NPP at 30 m resolution is larger than that at 1 km resolution. Land cover fraction is the most important vegetation factor to be considered in NPP spatial scaling, and slope is the most important topographical factor for NPP spatial scaling especially in mountainous areas, because of its influence on the lateral water redistribution, affecting water table, soil moisture and plant growth. Other factors including leaf area index (LAI) and elevation have small and additive effects on improving the spatial scaling

  13. Quantifying Human Appropriated Net Primary Productivity (HANPP) in a Ghanaian Cocoa System

    Science.gov (United States)

    Morel, A.; Adu-Bredu, S.; Adu Sasu, M.; Ashley Asare, R.; Boyd, E.; Hirons, M. A.; Malhi, Y.; Mason, J.; Norris, K.; Robinson, E. J. Z.; McDermott, C. L.

    2015-12-01

    Ghana is the second largest producer of cocoa (Theobroma cacoa), exporting approximately 18 percent of global volumes. These cocoa farms are predominantly small-scale, ranging in size from 2-4 hectares (ha). Traditionally, the model of cocoa expansion in Ghana relied on clearing new areas of forest and establishing a farm under remnant forest trees. This is increasingly less practical due to few unprotected forest areas remaining and management practices favoring close to full sun cocoa to maximize short-term yields. This study is part of a larger project, ECOLMITS, which is an interdisciplinary, ESPA-funded[1] initiative exploring the ecological limits of ecosystem system services (ESS) for alleviating poverty in small-scale agroforestry systems. The ecological study plots are situated within and around the Kakum National Forest, a well-protected, moist-evergreen forest of the Lower Guinea Forest region. Net primary productivity (NPP) is a measure of the rate at which carbon dioxide (CO2) is incorporated into plant tissues (e.g. canopy, stem and root). For this study, NPP was monitored in situ using methods developed by the Global Environmental Monitoring Network (GEM, http://gem.tropicalforests.ox.ac.uk/). By comparing NPP measured in intact forest and farms, the human appropriated NPP (HANPP) of this system can be estimated. The forest measures provide the "potential" NPP of the region, and then the reduction in NPP for farm plots is calculated for both land-cover change (HANPPLUC) and cocoa harvesting (HANPPHARV). The results presented are of the first year of NPP measurements across the cocoa landscape, including measurements from intact forest, logged forest and cocoa farms across a shade gradient and located at varying distances from the forest edge (e.g. 100 m, 500 m, 1 km and 5 km). These measures will have implications for carbon sequestration potential over the region and long-term sustainability of the Ghanaian cocoa sector. [1] Ecosystem Services for

  14. Effects of vegetation heterogeneity and surface topography on spatial scaling of net primary productivity

    Directory of Open Access Journals (Sweden)

    J. M. Chen

    2013-07-01

    Full Text Available Due to the heterogeneous nature of the land surface, spatial scaling is an inevitable issue in the development of land models coupled with low-resolution Earth system models (ESMs for predicting land-atmosphere interactions and carbon-climate feedbacks. In this study, a simple spatial scaling algorithm is developed to correct errors in net primary productivity (NPP estimates made at a coarse spatial resolution based on sub-pixel information of vegetation heterogeneity and surface topography. An eco-hydrological model BEPS-TerrainLab, which considers both vegetation and topographical effects on the vertical and lateral water flows and the carbon cycle, is used to simulate NPP at 30 m and 1 km resolutions for a 5700 km2 watershed with an elevation range from 518 m to 3767 m in the Qinling Mountain, Shanxi Province, China. Assuming that the NPP simulated at 30 m resolution represents the reality and that at 1 km resolution is subject to errors due to sub-pixel heterogeneity, a spatial scaling index (SSI is developed to correct the coarse resolution NPP values pixel by pixel. The agreement between the NPP values at these two resolutions is improved considerably from R2 = 0.782 to R2 = 0.884 after the correction. The mean bias error (MBE in NPP modelled at the 1 km resolution is reduced from 14.8 g C m−2 yr−1 to 4.8 g C m−2 yr−1 in comparison with NPP modelled at 30 m resolution, where the mean NPP is 668 g C m−2 yr−1. The range of spatial variations of NPP at 30 m resolution is larger than that at 1 km resolution. Land cover fraction is the most important vegetation factor to be considered in NPP spatial scaling, and slope is the most important topographical factor for NPP spatial scaling especially in mountainous areas, because of its influence on the lateral water redistribution, affecting water table, soil moisture and plant growth. Other factors including leaf area index (LAI and elevation have small and additive effects on improving

  15. Monthly Variation in Plant Biomass and Net Primary Productivity of a Mixed Deciduous Forest at Foothills of Kumaun Himalaya

    Directory of Open Access Journals (Sweden)

    Suresh Chandra PANT

    2012-03-01

    Full Text Available Variation in plant biomass and net primary productivity of a forest grazing land vegetation was analyzed in Tarai of Kumaun Himalaya near Kashipur. The vegetation was studied at monthly intervals from April 2007 to April 2008. Aboveground green biomass, dead biomass, litter biomass and belowground biomass were recorded as 216.93±42.42 g•m-2, 15.30±8.65 g•m-2, 5.52±2.31 g•m-2 and 132.91±41.70 g•m-2 respectively. Average total plant biomass was 365.15±70.23 g•m-2. The aboveground, belowground and litter production were 372.33 g•m-2, 339.70 g•m-2 and 13.91 g•m-2 respectively. Total net primary production was 712.03±23.07 g•m-2. The turnover rates were 1.17, 1.20 and 1.47 for aboveground, litter and belowground parts respectively. Based on system transfer function, the net surplus of organic material as the rate of disappearance was moderately half than the rate of dry matter accumulation.

  16. Spatial delineation of natural fractures and relation to gas production

    Energy Technology Data Exchange (ETDEWEB)

    Caramanica, F.P. [ResTech, Houston, TX (United States); Hill, D.G.

    1994-12-31

    In a Gas Research Institute sponsored study, enhanced formation image analysis was performed on twelve wells in the Antrim Shale, Michigan Basin. The analysis revealed that the abundance of open and partially open fractures as well as their degree of interconnection are controlling factors in gas production. Borehole maps show the interconnection with reference to the borehole. A fracture factor (Z{sub f}) was derived and plotted against gas flow rates for nine wells. Six wells treated with a single stage stimulation show a linear relationship between (Z{sub f}) and Q. Two were stimulated with a two-stage treatment and produced more gas than single-stage wells with comparable values of Z{sub f}. The methods of fracture analysis derived for the Antrim Shale should have immediate practical application to other unconventional and tight reservoir rocks.

  17. BUILDING MATERIALS MADE FROM FLUE GAS DESULFURIZATION BY-PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    Michael W. Grutzeck; Maria DiCola; Paul Brenner

    2006-03-30

    Flue gas desulphurization (FGD) materials are produced in abundant quantities by coal burning utilities. Due to environmental restrains, flue gases must be ''cleaned'' prior to release to the atmosphere. They are two general methods to ''scrub'' flue gas: wet and dry. The choice of scrubbing material is often defined by the type of coal being burned, i.e. its composition. Scrubbing is traditionally carried out using a slurry of calcium containing material (slaked lime or calcium carbonate) that is made to contact exiting flue gas as either a spay injected into the gas or in a bubble tower. The calcium combined with the SO{sub 2} in the gas to form insoluble precipitates. Some plants have been using dry injection of these same materials or their own Class C fly ash to scrub. In either case the end product contains primarily hannebachite (CaSO{sub 3} {center_dot} 1/2H{sub 2}O) with smaller amounts of gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). These materials have little commercial use. Experiments were carried out that were meant to explore the feasibility of using blends of hannebachite and fly ash mixed with concentrated sodium hydroxide to make masonry products. The results suggest that some of these mixtures could be used in place of conventional Portland cement based products such as retaining wall bricks and pavers.

  18. Production of bio-synthetic natural gas in Canada.

    Science.gov (United States)

    Hacatoglu, Kevork; McLellan, P James; Layzell, David B

    2010-03-15

    Large-scale production of renewable synthetic natural gas from biomass (bioSNG) in Canada was assessed for its ability to mitigate energy security and climate change risks. The land area within 100 km of Canada's network of natural gas pipelines was estimated to be capable of producing 67-210 Mt of dry lignocellulosic biomass per year with minimal adverse impacts on food and fiber production. Biomass gasification and subsequent methanation and upgrading were estimated to yield 16,000-61,000 Mm(3) of pipeline-quality gas (equivalent to 16-63% of Canada's current gas use). Life-cycle greenhouse gas emissions of bioSNG-based electricity were calculated to be only 8.2-10% of the emissions from coal-fired power. Although predicted production costs ($17-21 GJ(-1)) were much higher than current energy prices, a value for low-carbon energy would narrow the price differential. A bioSNG sector could infuse Canada's rural economy with $41-130 billion of investments and create 410,000-1,300,000 jobs while developing a nation-wide low-carbon energy system.

  19. Practices for Reducing Greenhouse Gas Emissions from Rice Production in Northeast Thailand

    Directory of Open Access Journals (Sweden)

    Noppol Arunrat

    2017-01-01

    Full Text Available Land management practices for rice productivity and carbon storage have been a key focus of research leading to opportunities for substantial greenhouse gas (GHG mitigation. The effects of land management practices on global warming potential (GWP and greenhouse gas intensity (GHGI from rice production within the farm gate were investigated. For the 13 study sites, soil samples were collected by the Land Development Department in 2004. In 2014, at these same sites, soil samples were collected again to estimate the soil organic carbon sequestration rate (SOCSR from 2004 to 2014. Surveys were conducted at each sampling site to record the rice yield and management practices. The carbon dioxide (CO2, methane (CH4, and nitrous oxide (N2O emissions, Net GWP, and GHGI associated with the management practices were calculated. Mean rice yield and SOCSR were 3307 kg·ha−1·year−1 and 1173 kg·C·ha−1·year−1, respectively. The net GWP varied across sites, from 819 to 5170 kg·CO2eq·ha−1·year−1, with an average value of 3090 kg·CO2eq·ha−1·year−1. GHGI ranged from 0.31 to 1.68 kg·CO2eq·kg−1 yield, with an average value of 0.97 kg·CO2eq·kg−1 yield. Our findings revealed that the amount of potassium (potash, K2O fertilizer application rate is the most significant factor explaining rice yield and SOCSR. The burning of rice residues in the field was the main factor determining GHGI in this area. An effective way to reduce GHG emissions and contribute to sustainable rice production for food security with low GHGI and high productivity is avoiding the burning of rice residues.

  20. The Dairy Greenhouse Gas Model: A Tool for estimating greenhouse gas emissions and the carbon footprint of dairy production systems

    Science.gov (United States)

    Greenhouse gas (GHG) emissions and their potential impact on the environment has become an important national and international concern. Animal agriculture is a recognized source of GHG emissions, but good information does not exist on the net emissions from our farms. A software tool called the Dai...

  1. Some modern notions on oil and gas reservoir production regulation

    Energy Technology Data Exchange (ETDEWEB)

    Lohrenz, J.; Monash, E.A.

    1980-05-21

    The historic rhetoric of oil and gas reservoir production regulations has been burdened with misconceptions. One was that most reservoirs are rate insensitive. Another was that a reservoir's decline is primarily a function of reservoir mechaism rather than a choice unconstrained by the laws of physics. Relieved of old notions like these, we introduce some modern notions, the most basic being that production regulation should have the purpose of obtaining the highest value from production per irreversible diminution of thermodynamically available energy. The laws of thermodynamics determine the available energy. What then is value. Value may include contributions other than production per se and purely monetary economic outcomes.

  2. Reactive oxygen species production and discontinuous gas exchange in insects.

    Science.gov (United States)

    Boardman, Leigh; Terblanche, John S; Hetz, Stefan K; Marais, Elrike; Chown, Steven L

    2012-03-07

    While biochemical mechanisms are typically used by animals to reduce oxidative damage, insects are suspected to employ a higher organizational level, discontinuous gas exchange mechanism to do so. Using a combination of real-time, flow-through respirometry and live-cell fluorescence microscopy, we show that spiracular control associated with the discontinuous gas exchange cycle (DGC) in Samia cynthia pupae is related to reactive oxygen species (ROS). Hyperoxia fails to increase mean ROS production, although minima are elevated above normoxic levels. Furthermore, a negative relationship between mean and mean ROS production indicates that higher ROS production is generally associated with lower . Our results, therefore, suggest a possible signalling role for ROS in DGC, rather than supporting the idea that DGC acts to reduce oxidative damage by regulating ROS production.

  3. Elusive prize: enormous coal gas potential awaits production technology breakthrough

    Energy Technology Data Exchange (ETDEWEB)

    Collison, M.

    2002-01-07

    The expanded gas pipeline grid has excess capacity, and gas resources are declining. There is increasing interest in development of Canada's resources of coalbed methane (CBM). The chairman of the Canadian Coalbed Methane Forum estimates that Canada has more than 3,000 trillion ft{sup 3} of gas awaiting suitable technology. PanCanadian and MGV Energy conducted a CBM exploration and pilot study on the Palliser spread in southern Alberta. Results from 23 of 75 wells are encouraging. The study is being accelerated and expanded to include an additional 50 wells elsewhere in Alberta. Some scientists anticipate commercial CBM production within two years. Problems facing developers include the large land holdings necessary for economic CBM production and the disposal of coal formation water. It is anticipated that U.S. technology will be modified and used. The potential for CBM development at Pictou in Nova Scotia and in British Columbia in the foothills is considered. 3 figs.

  4. Net Greenhouse Gas Budget and Soil Carbon Storage in a Field with Paddy–Upland Rotation with Different History of Manure Application

    Directory of Open Access Journals (Sweden)

    Fumiaki Takakai

    2017-06-01

    Full Text Available Methane (CH4 and nitrous oxide (N2O fluxes were measured from paddy–upland rotation (three years for soybean and three years for rice with different soil fertility due to preceding compost application for four years (i.e., 3 kg FW m−2 year−1 of immature or mature compost application plots and a control plot without compost. Net greenhouse gas (GHG balance was evaluated by integrating CH4 and N2O emissions and carbon dioxide (CO2 emissions calculated from a decline in soil carbon storage. N2O emissions from the soybean upland tended to be higher in the immature compost plot. CH4 emissions from the rice paddy increased every year and tended to be higher in the mature compost plot. Fifty-two to 68% of the increased soil carbon by preceding compost application was estimated to be lost during soybean cultivation. The major component of net GHG emission was CO2 (82–94% and CH4 (72–84% during the soybean and rice cultivations, respectively. Net GHG emissions during the soybean and rice cultivations were comparable. Consequently, the effects of compost application on the net GHG balance from the paddy–upland rotation should be carefully evaluated with regards to both advantages (initial input to the soil and disadvantages (following increases in GHG.

  5. Fluctuations and Correlations of net baryon number, electric charge, and strangeness: A comparison of lattice QCD results with the hadron resonance gas model

    CERN Document Server

    Bazavov, A; DeTar, C E; Ding, H -T; Gottlieb, Steven; Gupta, Rajan; Hegde, P; Heller, Urs; Karsch, F; Laermann, E; Levkova, L; Mukherjee, Swagato; Petreczky, P; Schmidt, Christian; Soltz, R A; Soeldner, W; Sugar, R; Vranas, Pavlos M

    2012-01-01

    We calculate the quadratic fluctuations of net baryon number, electric charge and strangeness as well as correlations among these conserved charges in (2+1)-flavor lattice QCD at zero chemical potential. Results in the continuum limit are obtained using calculations with tree level improved gauge and the highly improved staggered quark (HISQ) actions with almost physical light and strange quark masses at three different values of the lattice cut-off. We compare our results with the hadron resonance gas (HRG) model calculations and find agreement with HRG model results only for temperatures T < 150 MeV. We observe significant deviations in the temperature range 160 MeV < T < 170 MeV and qualitative differences in the behavior of the three conserved charge sectors. At $T \\simeq 160 MeV$ quadratic net baryon number fluctuations in QCD agree with HRG model calculations while, the net electric charge fluctuations in QCD are about 10% smaller and net strangeness fluctuations are about 20% larger. These fin...

  6. 75 FR 20271 - Oil and Gas and Sulphur Operations in the Outer Continental Shelf-Oil and Gas Production...

    Science.gov (United States)

    2010-04-19

    ... Minerals Management Service 30 CFR Part 250 RIN 1010-AD12 Oil and Gas and Sulphur Operations in the Outer Continental Shelf--Oil and Gas Production Requirements AGENCY: Minerals Management Service (MMS), Interior. ACTION: Final rule. SUMMARY: The MMS is amending the regulations regarding oil and natural gas production...

  7. 78 FR 59632 - Oil and Gas and Sulphur Operations on the Outer Continental Shelf-Oil and Gas Production Safety...

    Science.gov (United States)

    2013-09-27

    ... Bureau of Safety and Environmental Enforcement 30 CFR Part 250 RIN 1014-AA10 Oil and Gas and Sulphur Operations on the Outer Continental Shelf--Oil and Gas Production Safety Systems AGENCY: Bureau of Safety and... amend and update the regulations regarding oil and natural gas production by addressing issues such as...

  8. Greenhouse gas emissions in milk and dairy product chains

    DEFF Research Database (Denmark)

    Flysjö, Anna Maria

    Reducing greenhouse gas emissions from dairy products is one important step towards a more sustainable dairy sector. To ensure effective mitigation, reliable assessment methods are required. The present PhD thesis focuses on some of the most critical methodological aspects influencing the carbon...

  9. In vitro degradability and gas production parameters of Sericea ...

    African Journals Online (AJOL)

    Sericea lespedeza (Lespedeza cuneata) regrowth was harvested at early (ELP) or late (LLP) flowering stages, mixed with varying types and levels of roughage and fermented for 72 h in vitro, using the gas production (GP) technique. The roughage : lespedeza ratios were 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100.

  10. Chemical composition and in vitro gas production of vetch ( Vicia ...

    African Journals Online (AJOL)

    Chemical composition and in vitro gas production of vetch (Vicia sativa) and some browse and grass species from northern Ethiopia were investigated. Vetch (fresh cut) was sampled in September and vetch hay samples were taken in October both during the early dry period. Samples of the browse and grass species were ...

  11. Low Carbon Technology Options for the Natural Gas Electricity Production

    Science.gov (United States)

    The ultimate goal of this task is to perform environmental and economic analysis of natural gas based power production technologies (different routes) to investigate and evaluate strategies for reducing emissions from the power sector. It is a broad research area. Initially, the...

  12. Utilization of hydrogen gas production for electricity generation in ...

    African Journals Online (AJOL)

    Enterobacter aerogenes ADH-43 is a hydrogen gas (H2) producing mutant bacterium and a facultative anaerobic microbe. This double mutant was obtained by classical mutagenetically treated in order to enhance H2 production. In addition, this mutant has ability to degrade molasses from sugar factory as well as other ...

  13. Low nanopore connectivity limits gas production in Barnett formation

    Science.gov (United States)

    Hu, Qinhong; Ewing, Robert P.; Rowe, Harold D.

    2015-12-01

    Gas-producing wells in the Barnett Formation show a steep decline from initial production rates, even within the first year, and only 12-30% of the estimated gas in place is recovered. The underlying causes of these production constraints are not well understood. The rate-limiting step in gas production is likely diffusive transport from matrix storage to the stimulated fracture network. Transport through a porous material such as shale is controlled by both geometry (e.g., pore size distribution) and topology (e.g., pore connectivity). Through an integrated experimental and theoretical approach, this work finds that the Barnett Formation has sparsely connected pores. Evidence of low pore connectivity includes the sparse and heterogeneous presence of trace levels of diffusing solutes beyond a few millimeters from a sample edge, the anomalous behavior of spontaneous water imbibition, the steep decline in edge-accessible porosity observed in tracer concentrations following vacuum saturation, the low (about 0.2-0.4% by volume) level presence of Wood's metal alloy when injected at 600 MPa pressure, and high tortuosity from mercury injection capillary pressure. Results are consistent with an interpretation of pore connectivity based on percolation theory. Low pore connectivity of shale matrix limits its mass transfer interaction with the stimulated fracture network from hydraulic fracturing and serves as an important underlying cause for steep declines in gas production rates and a low overall recovery rate.

  14. Utilization of hydrogen gas production for electricity generation in ...

    African Journals Online (AJOL)

    Lecturer

    2012-05-03

    May 3, 2012 ... Enterobacter aerogenes ADH-43 is a hydrogen gas (H2) producing mutant bacterium and a facultative anaerobic microbe. This double mutant was obtained by classical mutagenetically treated in order to enhance H2 production. In addition, this mutant has ability to degrade molasses from sugar factory as.

  15. Exploring Estimates of Net Community Production and Export Along the Western Antarctic Peninsula (WAP), 1993-2014.

    Science.gov (United States)

    Ducklow, H. W.; Stukel, M. R.; Bowman, J. S.; Kim, H.; Cassar, N.; Eveleth, R.; Li, Z.; Doney, S. C.; Sailley, S. F.; Jickells, T. D.; Baker, A. R.; Chance, R.

    2016-12-01

    In this presentation, we will compare different estimates of net community production (NCP) and export production (EP), including both traditional (changes in nutrient inventories and biological incubations) and newer measurements (Oxygen-Argon ratio, Thorium-234 disequilibrium, Iodide accumulation). Palmer Long Term Ecological Research (PAL-LTER) has been conducting observations of core biogeochemical (nutrient and carbon inventories, sediment trap flux) and ecological (standing stocks, production and grazing rates) processes along the WAP since 1993. Datasets include both temporally-intensive (semiweekly, Oct-April) observations in two nearshore locations at Palmer Station, and regionally-extensive observations over a 200 x 700 km grid of stations extending across the shelf into deep ocean water (>3000 m) each January. These observations provide a long term temporal and spatial context for more recent and focused measurements of net NCP and EP from the euphotic zone. For example, long-term net drawdown of nitrate averaged 415 mmol N m-2 season-1 (33 gC m-2 Season-1) at Palmer Station and 557 mmol N m-2 Season-1 (45 gC m-2 Season-1) over the regional grid. In comparison, discrete bottle-based O2/Ar estimates of NCP averaged 44 mmol O2 m-2 d-1 (0.37 gC m-2 d-1) regionally in January 2008-11. Th234 export was 684 dpm-2 d-1 (0.15 gC m-2 d-1) in January 2012, sourced from 15NO3 uptake-based new production of 4.1 mmol N m-2 d-1 (0.37 gC m-2 d-1). Intercomparison of these estimates is not straightforward. Measurements are based on several elemental currencies (C, N, O2, Th). We do not fully understand the processes each method claims to address. Is NCP the same as new production? Different processes and their measurements proceed over timescales of hours (new and net PP) to weeks (O2/Ar, 234Th) to months (inventory drawdowns). As implied above, assignment of time duration of net drawdown processes is uncertain for changes in water column inventories. Models provide

  16. Analytical Modeling of Shale Hydraulic Fracturing and Gas Production

    Science.gov (United States)

    Xu, W.

    2012-12-01

    Shale gas is abundant all over the world. Due to its extremely low permeability, extensive stimulation of a shale reservoir is always required for its economic production. Hydraulic fracturing has been the primary method of shale reservoir stimulation. Consequently the design and optimization of a hydraulic fracturing treatment plays a vital role insuring job success and economic production. Due to the many variables involved and the lack of a simple yet robust tool based on fundamental physics, horizontal well placement and fracturing job designs have to certain degree been a guessing game built on previous trial and error experience. This paper presents a method for hydraulic fracturing design and optimization in these environments. The growth of a complex hydraulic fracture network (HFN) during a fracturing job is equivalently represented by a wiremesh fracturing model (WFM) constructed on the basis of fracture mechanics and mass balance. The model also simulates proppant transport and placement during HFN growth. Results of WFM simulations can then be used as the input into a wiremesh production model (WPM) constructed based on WFM. WPM represents gas flow through the wiremesh HFN by an elliptic flow and the flow of gas in shale matrix by a novel analytical solution accounting for contributions from both free and adsorbed gases stored in the pore space. WPM simulation is validated by testing against numerical simulations using a commercially available reservoir production simulator. Due to the analytical nature of WFM and WPM, both hydraulic fracturing and gas production simulations run very fast on a regular personal computer and are suitable for hydraulic fracturing job design and optimization. A case study is presented to demonstrate how a non-optimized hydraulic fracturing job might have been optimized using WFM and WPM simulations.Fig. 1. Ellipsoidal representation of (a) stimulated reservoir and (b) hydraulic fracture network created by hydraulic

  17. The production of carbon dioxide from flue gas by membrane gas absorption

    NARCIS (Netherlands)

    Feron, P.H.M.; Jansen, A.E.

    1997-01-01

    The use of membrane gas absorption for carbon dioxide production from flue gases is discussed with special reference to the combined supply of heat and carbon dioxide to greenhouses. Novel absorption liquids are introduced which show an improved performance in terms of system stability and mass

  18. Synthesis gas production via hybrid steam reforming of natural gas and bio-liquids

    NARCIS (Netherlands)

    Balegedde Ramachandran, P.

    2013-01-01

    This thesis deals with (catalytic) steam reforming of bio-liquids for the production of synthesis gas. Glycerol, both crude from the biodiesel manufacturing and refined, and pyrolysis oil are tested as bio-based feedstocks. Liquid bio-based feeds could be preferred over inhomogeneous fibrous solid

  19. Optimizing Photosynthetic and Respiratory Parameters Based on the Seasonal Variation Pattern in Regional Net Ecosystem Productivity Obtained from Atmospheric Inversion

    Science.gov (United States)

    Chen, Z.; Chen, J.; Zheng, X.; Jiang, F.; Zhang, S.; Ju, W.; Yuan, W.; Mo, G.

    2014-12-01

    In this study, we explore the feasibility of optimizing ecosystem photosynthetic and respiratory parameters from the seasonal variation pattern of the net carbon flux. An optimization scheme is proposed to estimate two key parameters (Vcmax and Q10) by exploiting the seasonal variation in the net ecosystem carbon flux retrieved by an atmospheric inversion system. This scheme is implemented to estimate Vcmax and Q10 of the Boreal Ecosystem Productivity Simulator (BEPS) to improve its NEP simulation in the Boreal North America (BNA) region. Simultaneously, in-situ NEE observations at six eddy covariance sites are used to evaluate the NEE simulations. The results show that the performance of the optimized BEPS is superior to that of the BEPS with the default parameter values. These results have the implication on using atmospheric CO2 data for optimizing ecosystem parameters through atmospheric inversion or data assimilation techniques.

  20. Collaborative Product/Service-Systems – On conceptualisation of PSS offerings and business nets

    DEFF Research Database (Denmark)

    Mougaard, Krestine; Neugebauer, Line Maria; McAloone, Tim C.

    2012-01-01

    Collaborative PSS development and operation, where multiple stakeholders are involved, is an emerging research area. This articles looks at the intra and inter-organisational company considerations in the industry case of company collaboration in the maritime branch. Initial steps are taken towar...... a framework that aligns service strategies and their unique value proposition with a set of business nets that seeks lights on the value-logic and management mechanisms to design and control each network....

  1. UV sensitivity of planktonic net community production in ocean surface waters

    OpenAIRE

    Regaudie de Gioux, Aurore; Agustí, Susana; Duarte, Carlos M.

    2014-01-01

    The net plankton community metabolism of oceanic surface waters is particularly important as it more directly affects the partial pressure of CO2 in surface waters and thus the air-sea fluxes of CO2. Plankton communities in surface waters are exposed to high irradiance that includes significant ultraviolet blue (UVB, 280-315 nm) radiation. UVB radiation affects both photosynthetic and respiration rates, increase plankton mortality rates, and other metabolic and chemical processes. Here we tes...

  2. Halogens in oil and gas production-associated wastewater.

    Science.gov (United States)

    Harkness, J.; Warner, N. R.; Dwyer, G. S.; Mitch, W.; Vengosh, A.

    2014-12-01

    Elevated chloride and bromide in oil and gas wastewaters that are released to the environment are one of the major environmental risks in areas impacted by shale gas development [Olmstead et al.,2013]. In addition to direct contamination of streams, the potential for formation of highly toxic disinfection by-products (DBPs) in drinking water in utilities located downstream from disposal sites poses a serious risk to human health. Here we report on the occurrence of iodide in oil and gas wastewater. We conducted systematic measurements of chloride, bromide, and iodide in (1) produced waters from conventional oil and gas wells from the Appalachian Basin; (2) hydraulic fracturing flowback fluids from unconventional Marcellus and Fayetteville shale gas, (3) effluents from a shale gas spill site in West Virginia; (4) effluents of oil and gas wastewater disposed to surface water from three brine treatment facilities in western Pennsylvania; and (5) surface waters downstream from the brine treatment facilities. Iodide concentration was measured by isotope dilution-inductively coupled plasma-mass spectrometry, which allowed for a more accurate measurement of iodide in a salt-rich matrix. Iodide in both conventional and unconventional oil and gas produced and flowback waters varied from 1 mg/L to 55 mg/L, with no systematic enrichment in hydraulic fracturing fluids. The similarity in iodide content between the unconventional Marcellus flowback waters and the conventional Appalachian produced waters clearly indicate that the hydraulic fracturing process does not induce additional iodide and the iodide content is related to natural variations in the host formations. Our data show that effluents from the brine treatment facilities have elevated iodide (mean = 20.9±1 mg/L) compared to local surface waters (0.03± 0.1 mg/L). These results indicate that iodide, in addition to chloride and bromide in wastewater from oil and gas production, poses an additional risk to downstream

  3. In vitro cumulative gas production techniques: history, methodological considerations and challenges

    NARCIS (Netherlands)

    Rymer, C.; Huntington, J.A.; Williams, B.A.; Givens, D.I.

    2005-01-01

    Methodology used to measure in vitro gas production is reviewed to determine impacts of sources of variation on resultant gas production profiles (GPP). Current methods include measurement of gas production at constant pressure (e.g., use of gas tight syringes), a system that is inexpensive, but may

  4. Annual Net Community Production in the Western Subtropical North Pacific Determined from Argo-O2 Measurements

    Science.gov (United States)

    Yang, B.; Emerson, S. R.; Bushinsky, S. M.

    2016-02-01

    Export of organic carbon from the surface ocean to depth (the biological pump) helps maintain the pCO2 of the atmosphere and the O2 content of the oxygen minimum zones of the ocean. In the upper ocean, at steady state over a seasonal cycle the net organic carbon export is equal to the Annual Net Community Production (ANCP). The geographic distribution of this quantity determined by satellite-predicted Net Primary Production (NPP) and the recycling efficiency in the euphotic zone is more heterogeneous than the limited experimental estimates of ANCP. We evaluate the relationship between these two estimates of ANCP in the subtropical Western North Pacific Ocean ( 165o E and 20o N) using oxygen measurements on Argo Floats. In January of 2015 we deployed four floats with Anderaa oxygen sensors attached to a 60 cm stick on top of the float end cap, which can be readily calibrated against atmospheric pO2. We present data from these floats and air-sea oxygen flux calculations. The degree of oxygen supersaturation in summer is 1-2 percent, and in winter it fluctuates between being over and undersaturated. Evaluating the role of bubbles in winter is critical to an accurate determination of the annual flux. While there is not a full year of data at the time of writing this abstract, there will be when the Ocean Science meeting is held. So far, after nine months of measurements, there is a net flux of oxygen to the atmosphere, indicating that photosynthesis exceeds respiration. In February we will present a full annual cycle of air-sea oxygen flux and an estimate of ANCP in this very rarely studied region of the ocean.

  5. Innovative technologies for greenhouse gas emission reduction in steel production

    Directory of Open Access Journals (Sweden)

    D. Burchart-Korol

    2016-01-01

    Full Text Available The main goal of the study was to present the most significant technological innovations aiming at reduction of greenhouse gas emission in steel production. Reduction of greenhouse gas and dust pollution is a very important aspect in the iron and steel industry. New solutions are constantly being searched for to reduce greenhouse gases (GHG. The article presents the most recent innovative technologies which may be applied in the steel industry in order to limit the emission of GHG. The significance of CCS (CO2 Capture and Storage and CCU (CO2 Capture and Utilization in the steel industry are also discussed.

  6. Projected Alaskan royalty gas production and its relationship to projected natural gas demand

    Energy Technology Data Exchange (ETDEWEB)

    Dobey, P.L.; O' Connor, K.M.; Gilbreth, O.K.; Miller, J.C.; Hamilton, H.H.

    1976-04-01

    Using conservative parameters for the natural gas surplus analysis, a Prudhoe Bay field royalty surplus above residential-commercial needs was found for all pipeline capacities. When the more probable pipeline throughputs are considered (2.0 and 2.5 billion cubic feet per day), surpluses of over 70 percent of the pipeline royalty capacities are present until 1990. The probable effect of future estimated energy production and proven additional gas reserves will insure a surplus above 90 percent of royalty gas for the entire twenty-year period in the 2.0 Bcf per day and 2.5 Bcf per day cases. The assumption that royalty gas will be needed to supply future power demands in the greater Anchorage area must be weighted against the high probability that additional coal-fired generators and hydroelectric power development will be available. After the present commitments of working gas are exhausted, the probable addition of a new alternate energy source added to the likelihood of additional commitments of working gas being acquired by suppliers would insure a solid royalty surplus after 1990.

  7. Challenges, uncertainties, and issues facing gas production from gas-hydrate deposits

    Science.gov (United States)

    Moridis, G.J.; Collett, T.S.; Pooladi-Darvish, M.; Hancock, S.; Santamarina, C.; Boswel, R.; Kneafsey, T.; Rutqvist, J.; Kowalsky, M.B.; Reagan, M.T.; Sloan, E.D.; Sum, A.K.; Koh, C.A.

    2011-01-01

    The current paper complements the Moridis et al. (2009) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas-hydrate (GH) petroleum system; to discuss advances, requirements, and suggested practices in GH prospecting and GH deposit characterization; and to review the associated technical, economic, and environmental challenges and uncertainties, which include the following: accurate assessment of producible fractions of the GH resource; development of methods for identifying suitable production targets; sampling of hydrate-bearing sediments (HBS) and sample analysis; analysis and interpretation of geophysical surveys of GH reservoirs; well-testing methods; interpretation of well-testing results; geomechanical and reservoir/well stability concerns; well design, operation, and installation; field operations and extending production beyond sand-dominated GH reservoirs; monitoring production and geomechanical stability; laboratory investigations; fundamental knowledge of hydrate behavior; the economics of commercial gas production from hydrates; and associated environmental concerns. ?? 2011 Society of Petroleum Engineers.

  8. A new net primary production estimating model using NOAA-AVHRR applied to the Haihe Basin, China

    Science.gov (United States)

    Xu, Xingang; Wu, Bingfang; Li, Qiangzi; Meng, Jihua; Zhang, Fengli

    2006-10-01

    Terrestrial net primary production (NPP), as an important component of carbon cycle on land, not only indicates directly the production level of vegetation community on land, but also shows the status of terrestrial ecosystem. What's more, NPP is also a determinant of carbon sinks on land and a key regulator of ecological processes, including interactions among tropic levels. In the study, three existing models are combined with each other to assess net primary production in Haihe Basin, China. The photosynthetically active radiation (PAR) model of Monteith is used for the calculation of absorbed photosynthetically active radiation (APAR), the light utilization efficiency model of Potter et al. is used for determining the light utilization efficiency, and the surface energy balance system (SEBS) of Su is used into Potter's model to describe water stress in land wetness conditions. To assess NPP, We use NOAA-AVHRR data from November 2003 to September 2004 and the corresponding daily data of temperature and hours of sunshine obtained from meteorological stations in Haihe Basin, China. After atmospheric, geometrical and radiant corrections, every ten days NOAA data are processed to become an image of NDVI by means of the maximal value composition method (MVC) in order to eliminate some noises. Using these data, we compute NPP in spring season and spring season of 2004 in Haihe Basin, China. The result shows, in Haihe Basin, NPP for spring season is averaged to 336.10gC•m -2, and 709.16 gC•m -2 for autumn season. In spatial distribution, NPP is greater in both ends than in middle for spring season, and decrease increasingly from north to south for autumn season. Future work should rely on the integration of high and low resolution images to assess net primary production, which will probably have more accurately estimation.

  9. Value-Added Products from Remote Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    Lyle A. Johnson

    2002-03-15

    In Wyoming and throughout the United States, there are natural gas fields that are not producing because of their remoteness from gas pipelines. Some of these fields are ideal candidates for a cogeneration scheme where components suitable for chemical feedstock or direct use, such as propane and butane, are separated. Resulting low- to medium-Btu gas is fired in a gas turbine system to provide power for the separation plant. Excess power is sold to the utility, making the integrated plant a true cogeneration facility. This project seeks to identify the appropriate technologies for various subsystems of an integrated plant to recover value-added products from wet gas and/or retrograde condensate reservoirs. Various vendors and equipment manufacturers will be contacted and a data base consisting of feedstock constraints and output specifications for various subsystems and components will be developed. Based on vendor specifications, gas reservoirs suited for value-added product recovery will be identified. A candidate reservoir will then be selected, and an optimum plant layout will be developed. A facility will then be constructed and operated. The project consists of eight subtasks: Compilation of Reservoir Data; Review of Treatment and Conditioning Technologies; Review of Product Recovery and Separation Technologies; Development of Power Generation System; Integrated Plant Design for Candidate Field; System Fabrication; System Operation and Monitoring; and Economic Evaluation and Reporting. The first five tasks have been completed and the sixth is nearly complete. Systems Operations and Monitoring will start next year. The Economic Evaluation and Reporting task will be a continuous effort for the entire project. The reservoir selected for the initial demonstration of the process is the Burnt Wagon Field, Natrona County, Wyoming. The field is in a remote location with no electric power to the area and no gas transmission line. The design for the gas processing

  10. X(3872 production and absorption in a hot hadron gas

    Directory of Open Access Journals (Sweden)

    L.M. Abreu

    2016-10-01

    Full Text Available We calculate the time evolution of the X(3872 abundance in the hot hadron gas produced in the late stage of heavy ion collisions. We use effective field Lagrangians to obtain the production and dissociation cross sections of X(3872. In this evaluation we include diagrams involving the anomalous couplings πD⁎D¯⁎ and XD¯⁎D⁎ and also the couplings of the X(3872 with charged D and D⁎ mesons. With these new terms the X(3872 interaction cross sections are much larger than those found in previous works. Using these cross sections as input in rate equations, we conclude that during the expansion and cooling of the hadronic gas, the number of X(3872, originally produced at the end of the mixed QGP/hadron gas phase, is reduced by a factor of 4.

  11. Near-Net-Shape Production of Hollow Titanium Alloy Components via Electrochemical Reduction of Metal Oxide Precursors in Molten Salts

    Science.gov (United States)

    Hu, Di; Xiao, Wei; Chen, George Z.

    2013-04-01

    Metal oxide precursors (ca. 90 wt pct Ti, 6 wt pct Al, and 4 wt pct V) were prepared with a hollow structure in various shapes such as a sphere, miniature golf club head, and cup using a one-step solid slip-casting process. The precursors were then electro-deoxidized in molten calcium chloride [3.2 V, 1173 K (900 °C)] against a graphite anode. After 24 hours of electrolysis, the near-net-shape Ti-6Al-4V product maintained its original shape with controlled shrinkage. Oxygen contents in the Ti-6Al-4V components were typically below 2000 ppm. The maximum compressive stress and modulus of electrolytic products obtained in this work were approximately 243 MPa and 14 GPa, respectively, matching with the requirement for medical implants. Further research directions are discussed for mechanical improvement of the products via densification during or after electrolysis. This simple, fast, and energy-efficient near-net-shape manufacturing method could allow titanium alloy components with desired geometries to be prepared directly from a mixture of metal oxides, promising an innovative technology for the low-cost production of titanium alloy components.

  12. Forest cockchafer larvae as methane production hotspots in soils and their importance for net soil methane fluxes

    Science.gov (United States)

    Görres, Carolyn-Monika; Kammann, Claudia; Murphy, Paul; Müller, Christoph

    2016-04-01

    Certain groups of soil invertebrates, namely scarab beetles and millipedes, are capable of emitting considerable amounts of methane due to methanogens inhabiting their gut system. It was already pointed out in the early 1990's, that these groups of invertebrates may represent a globally important source of methane. However, apart from termites, the importance of invertebrates for the soil methane budget is still unknown. Here, we present preliminary results of a laboratory soil incubation experiment elucidating the influence of forest cockchafer larvae (Melolontha hippocastani FABRICIUS) on soil methane cycling. In January/February 2016, two soils from two different management systems - one from a pine forest (extensive use) and one from a vegetable field (intensive use) - were incubated for 56 days either with or without beetle larvae. Net soil methane fluxes and larvae methane emissions together with their stable carbon isotope signatures were quantified at regular intervals to estimate gross methane production and gross methane oxidation in the soils. The results of this experiment will contribute to testing the hypothesis of whether methane production hotspots can significantly enhance the methane oxidation capacity of soils. Forest cockchafer larvae are only found in well-aerated sandy soils where one would usually not suspect relevant gross methane production. Thus, besides quantifying their contribution to net soil methane fluxes, they are also ideal organisms to study the effect of methane production hotspots on overall soil methane cycling. Funding support: Reintegration grant of the German Academic Exchange Service (DAAD) (#57185798).

  13. Gas production after reaction of sodium bicarbonate and hydrochloric acid.

    Science.gov (United States)

    Fordtran, J S; Morawski, S G; Santa Ana, C A; Rector, F C

    1984-11-01

    Ingestion of sodium bicarbonate has been implicated as one of the proximate causes of spontaneous gastric rupture. However, the volume and rate of gas released from the reaction of ingested sodium bicarbonate and gastric acid has not been previously studied in detail. We, therefore, developed an in vitro method for measuring gas release after addition of sodium bicarbonate to a solution containing hydrochloric acid. From the results of our studies, we conclude that even though hydrochloric acid and sodium bicarbonate react instantaneously, the resulting gas production is slow, mainly because CO2 produced from the dehydration of carbonic acid dissolves in water and is only slowly released into the gas phase. The major exogenous factors that determine the rate of gas release are the volume of the solution, the quantity of reactants, the air volume over the reaction mixture, the partial pressure of CO2 of the acid solution before the addition of bicarbonate, and the stirring rate. The presence of food, alcohol, and carbonic anhydrase had relatively little if any effect. Based on our results, we believe that ingestion of the recommended dose of sodium bicarbonate (one-half teaspoon) would result in only small amounts of sudden gas release, probably not enough to be an important factor in causing spontaneous gastric rupture. On the other hand, we measured the amount of sodium bicarbonate that people actually select to take for indigestion, and all exceeded the recommended dose. Some people selected doses of bicarbonate that would result in several hundred milliliters of gas release within 3 min; it seems likely that such injudicious ingestion of sodium bicarbonate, if taken when the stomach was distended with air, food, and liquid, could be an important factor in spontaneous gastric rupture.

  14. Liquefied natural gas (LNG) : production, storage and handling. 7. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Kalra, S.; Jaron, K.; Adragna, M.; Coyle, S.; Foley, C.; Hawryn, S.; Martin, A.; McConnell, J. (eds.)

    2003-07-01

    This Canadian Standard on the production, storage and handling of liquefied natural gas (LNG) was prepared by the Technical Committee on Liquefied Natural Gas under the jurisdiction of the Steering Committee on Oil and Gas Industry Systems and Materials. It establishes the necessary requirements for the design, installation and safe operation of LNG facilities. The Standard applies to the design, location, construction, operation and maintenance of facilities at any location of the liquefaction of natural gas and for the storage, vaporization, transfer, handling and truck transport of LNG. The training of personnel involved is also included as well as containers for LNG storage, including insulated vacuum systems. It includes non-mandatory guidelines for small LNG facilities but does not apply to the transportation of refrigerants, LNG by rail, marine vessel or pipeline. This latest edition contains changes in working of seismic design requirements and minor editorial changes to several clauses to bring the Standard closer to the US National Fire Protection Association's Committee on Liquefied Natural Gas Standard while maintaining Canadian regulatory requirements. The document is divided into 12 sections including: general requirements; plant site provisions; process equipment; stationary LNG storage containers; vaporization facilities; piping system and components; instrumentation and electrical services; transfer of LNG and refrigerants; fire protection, safety and security; and, operating, maintenance and personnel training. This Standard, like all Canadian Standards, was subject to periodic review and was most recently reaffirmed in 2003. 6 tabs., 6 figs., 3 apps.

  15. Global Human Appropriation of Net Primary Production for Biomass Consumption in the European Union, 1986–2007

    Science.gov (United States)

    Erb, Karl‐Heinz; Haberl, Helmut

    2015-01-01

    Summary The ongoing globalization process strengthens the connections between different geographic regions through trade. Biomass products, such as food, fiber, or bioenergy, are increasingly traded globally, thereby leading to telecouplings between distant, seemingly unrelated regions. For example, restrictions for agricultural production or changes in bioenergy demand in Europe or the United States might contribute to deforestation in Latin America or Sub‐Saharan Africa. One approach to analyze trade‐related land‐use effects of the global socioeconomic biomass metabolism is the “embodied human appropriation of net primary production” or eHANPP. eHANPP accounts allocate to any product the entire amount of the human appropriation of net primary production (HANPP) that emerges throughout its supply chain. This allows consumption‐based accounts to move beyond simple area‐demand approaches by taking differences in natural productivity as well as in land‐use intensity into account, both across land‐use types as well as across world regions. In this article, we discuss the eHANPP related to the European Union's (EU) consumption of biomass products in the period 1986–2007, based on a consistent global trade data set derived from bilateral data. We find a considerable dependency of the EU on the appropriation of biological productivity outside its own boundaries, with increasing reliance on Latin America as a main supplier. By using the EU as an illustrative example, we demonstrate the usefulness of eHANPP for assessing land‐use impacts caused by nations’ socioeconomic activities and conclude that the eHANPP approach can provide useful information to better manage ecosystems globally in the face of an increasingly interconnected world. PMID:27524879

  16. Fuel gas production from animal and agricultural residues and biomass

    Energy Technology Data Exchange (ETDEWEB)

    Wise, D. L; Wentworth, R. L

    1978-05-30

    Progress was reported by all contractors. Topics presented include: solid waste to methane gas; pipeline fuel gas from an environmental cattle feed lot; heat treatment of organics for increasing anaerobic biodegradability; promoting faster anaerobic digestion; permselective membrane control of algae and wood digesters for increased production and chemicals recovery; anaerobic fermentation of agricultural residues; pilot plant demonstration of an anaerobic, fixed-film bioreactor for wastewater treatment; enhancement of methane production in the anaerobic diegestion of sewage; evaluation of agitation concepts for biogasification of sewage sludge; operation of a 50,000 gallon anaerobic digester; biological conversion of biomass to methane; dirt feedlot residue experiments; anaerobic fermentation of livestock and crop residues; current research on methanogenesis in Europe; and summary of EPA programs in digestion technology. (DC)

  17. High-resolution view of the spring bloom initiation and net community production in the Subantarctic Southern Ocean using glider data

    CSIR Research Space (South Africa)

    Thomalla, Sandy J

    2015-07-01

    Full Text Available physics highlighting sensitivities of different bloom detection methods to different environmental processes. Model results show that in early spring (September to mid-November) increased rates of net community production (NCP) are strongly affected...

  18. Net primary productivity collected from New Horizon in Gulf of California and North Pacific Ocean from 2004-07-14 to 2008-08-06 (NCEI Accession 0130076)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Net primary productivity determined from 13C-labeled in situ incubations. Water collected via Niskin bottle was incubated with labeled bicarbonate for 24 hours at...

  19. Production of hydrogen by thermocatalytic cracking of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Muradov, N. [Florida Solar Energy Center, Cocoa, FL (United States)

    1996-10-01

    The conventional methods of hydrogen production from natural gas (for example, steam reforming and partial oxidation) are complex, multi-step processes that produce large quantities of CO{sub 2}. The main goal of this project is to develop a technologically simple process for hydrogen production from natural gas (NG) and other hydrocarbon fuels via single-step decomposition of hydrocarbons. This approach eliminates or significantly reduces CO{sub 2} emission. Carbon is a valuable by-product of this process, whereas conventional methods of hydrogen production from NG produce no useful by-products. This approach is based on the use of special catalysts that reduce the maximum temperature of the process from 1400-1500{degrees}C (thermal non-catalytic decomposition of methane) to 500-900{degrees}C. Transition metal based catalysts and various forms of carbon are among the candidate catalysts for the process. This approach can advantageously be used for the development of compact NG reformers for on-site production of hydrogen-methane blends at refueling stations and, also, for the production of hydrogen-rich gas for fuel cell applications. The author extended the search for active methane decomposition catalysts to various modifications of Ni-, Fe-, Mo- and Co-based catalysts. Variation in the operational parameters makes it possible to produce H{sub 2}-CH{sub 4} blends with a wide range of hydrogen concentrations that vary from 15 to 98% by volume. The author found that Ni-based catalysts are more effective at temperatures below 750{degrees}C, whereas Fe-based catalysts are effective at temperatures above 800{degrees}C for the production of hydrogen with purity of 95% v. or higher. The catalytic pyrolysis of liquid hydrocarbons (pentane, gasoline) over Fe-based catalyst was conducted. The author observed the production of a hydrogen-rich gas (hydrogen concentration up to 97% by volume) at a rate of approximately 1L/min.mL of hydrocarbon fuel.

  20. Trash-to-Gas: Converting Space Trash into Useful Products

    Science.gov (United States)

    Caraccio, Anne J.; Hintze, Paul E.

    2013-01-01

    NASA's Logistical Reduction and Repurposing (LRR) project is a collaborative effort in which NASA is determined to reduce total logistical mass through reduction, reuse and recycling of various wastes and components of long duration space missions and habitats. LRR is focusing on four distinct advanced areas of study: Advanced Clothing System, Logistics-to-Living, Heat Melt Compactor and Trash to Supply Gas (TtSG). The objective of TtSG is to develop technologies that convert material waste, human waste and food waste into high-value products. High-value products include life support oxygen and water, rocket fuels, raw material production feedstocks, and other energy sources. There are multiple pathways for converting waste to products involving single or multi-step processes. This paper discusses thermal oxidation methods of converting waste to methane. Different wastes, including food, food packaging, Maximum Absorbent Garments (MAGs), human waste simulants, and cotton washcloths have been evaluated in a thermal degradation reactor under conditions promoting pyrolysis, gasification or incineration. The goal was to evaluate the degradation processes at varying temperatures and ramp cycles and to maximize production of desirable products and minimize high molecular weight hydrocarbon (tar) production. Catalytic cracking was also evaluated to minimize tar production. The quantities of CO2, CO, CH4, and H2O were measured under the different thermal degradation conditions. The conversion efficiencies of these products were used to determine the best methods for producing desired products.

  1. Trash to Gas: Converting Space Trash into Useful Products

    Science.gov (United States)

    Nur, Mononita

    2013-01-01

    NASA's Logistical Reduction and Repurposing (LRR) project is a collaborative effort in which NASA is determined to reduce total logistical mass through reduction, reuse and recycling of various wastes and components of long duration space missions and habitats. LRR is focusing on four distinct advanced areas of study: Advanced Clothing System, Logistics-to-Living, Heat Melt Compactor and Trash to Supply Gas (TtSG). The objective of TtSG is to develop technologies that convert material waste, human waste and food waste into high-value products. High-value products include life support oxygen and water, rocket fuels, raw material production feedstocks, and other energy sources. There are multiple pathways for converting waste to products involving single or multi-step processes. This paper discusses thermal oxidation methods of converting waste to methane. Different wastes, including food, food packaging, Maximum Absorbent Garments (MAGs), human waste simulants, and cotton washcloths have been evaluated in a thermal degradation reactor under conditions promoting pyrolysis, gasification or incineration. The goal was to evaluate the degradation processes at varying temperatures and ramp cycles and to maximize production of desirable products and minimize high molecular weight hydrocarbon (tar) production. Catalytic cracking was also evaluated to minimize tar production. The quantities of C02, CO, CH4, and H20 were measured under the different thermal degradation conditions. The conversion efficiencies of these products were used to determine the best methods for producing desired products.

  2. Analysis to determine the maximum dimensions of flexible apertures in sensored security netting products.

    Energy Technology Data Exchange (ETDEWEB)

    Murton, Mark; Bouchier, Francis A.; vanDongen, Dale T.; Mack, Thomas Kimball; Cutler, Robert P; Ross, Michael P.

    2013-08-01

    Although technological advances provide new capabilities to increase the robustness of security systems, they also potentially introduce new vulnerabilities. New capability sometimes requires new performance requirements. This paper outlines an approach to establishing a key performance requirement for an emerging intrusion detection sensor: the sensored net. Throughout the security industry, the commonly adopted standard for maximum opening size through barriers is a requirement based on square inchestypically 96 square inches. Unlike standard rigid opening, the dimensions of a flexible aperture are not fixed, but variable and conformable. It is demonstrably simple for a human intruder to move through a 96-square-inch opening that is conformable to the human body. The longstanding 96-square-inch requirement itself, though firmly embedded in policy and best practice, lacks a documented empirical basis. This analysis concluded that the traditional 96-square-inch standard for openings is insufficient for flexible openings that are conformable to the human body. Instead, a circumference standard is recommended for these newer types of sensored barriers. The recommended maximum circumference for a flexible opening should be no more than 26 inches, as measured on the inside of the netting material.

  3. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity.

    Science.gov (United States)

    Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D; Jones, Edward O; Hatano, Ryusuke

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959-2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from -1.26MgCha(-1)yr(-1) in 1959-0.26 Mg Cha(-1)yr(-1) in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959-2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. How technology and price affect US tight gas potential. Part 1. Technology of tight gas production

    Energy Technology Data Exchange (ETDEWEB)

    Veatch, R.W. Jr.; Baker, O.

    1983-01-01

    The tight gas resource in the US currently is estimated at 900 tcf, of which 600 tcf is considered technically recoverable. This gas is found in basins that cover a prospective area of one million square miles (one million sections). Of these, ca 120,000 sections are potentially productive. The tight gas picture is composed of many different and often complex reservoirs, ranging from the shallow horizons of the Northern Great Plains to the deep formations of the Rocky Mountains. These reservoirs range from the blanket-like formations that cover wide geographical areas to the highly lenticular zones such as those common to the Mesa Verde. The one thing they have in common is microdarcy permeabilities. A good perspective of the challenge is obvious when such permeability values are realized to be similar to that of cement normally used for oil and gas well casing strings. The advanced technology presumes improved exploration knowledge, longer fractures, higher fracture conductivity, and a higher density of well development. Advanced technology is particularly necessary for lenticular reservoirs which contain ca 40% of the recoverable gas.

  5. An Overview of Natural Gas Conversion Technologies for Co-Production of Hydrogen and Value-Added Solid Carbon Products

    Energy Technology Data Exchange (ETDEWEB)

    Dagle, Robert A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dagle, Vanessa [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bearden, Mark D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Holladay, Jamelyn D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Krause, Theodore R. [Argonne National Lab. (ANL), Argonne, IL (United States); Ahmed, Shabbir [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-11-16

    This report was prepared in response to the U.S. Department of Energy Fuel Cell Technologies Office Congressional Appropriation language to support research on carbon-free production of hydrogen using new chemical processes that utilize natural gas to produce solid carbon and hydrogen. The U.S. produces 9-10 million tons of hydrogen annually with more than 95% of the hydrogen produced by steam-methane reforming (SMR) of natural gas. SMR is attractive because of its high hydrogen yield; but it also converts the carbon to carbon dioxide. Non-oxidative thermal decomposition of methane to carbon and hydrogen is an alternative to SMR and produces CO2-free hydrogen. The produced carbon can be sold as a co-product, thus providing economic credit that reduces the delivered net cost of hydrogen. The combination of producing hydrogen with potentially valuable carbon byproducts has market value in that this allows greater flexibility to match the market prices of hydrogen and carbon. That is, the higher value product can subsidize the other in pricing decisions. In this report we highlight the relevant technologies reported in the literature—primarily thermochemical and plasma conversion processes—and recent research progress and commercial activities. Longstanding technical challenges include the high energetic requirements (e.g., high temperatures and/or electricity requirements) necessary for methane activation and, for some catalytic processes, the separation of solid carbon product from the spent catalyst. We assess current and new carbon product markets that could be served given technological advances, and we discuss technical barriers and potential areas of research to address these needs. We provide preliminary economic analysis for these processes and compare to other emerging (e.g., electrolysis) and conventional (e.g., SMR) processes for hydrogen production. The overarching conclusion of this study is that the cost of hydrogen can be potentially

  6. Organic Substances from Unconventional Oil and Gas Production in Shale

    Science.gov (United States)

    Orem, W. H.; Varonka, M.; Crosby, L.; Schell, T.; Bates, A.; Engle, M.

    2014-12-01

    Unconventional oil and gas (UOG) production has emerged as an important element in the US and world energy mix. Technological innovations in the oil and gas industry, especially horizontal drilling and hydraulic fracturing, allow for the enhanced release of oil and natural gas from shale compared to conventional oil and gas production. This has made commercial exploitation possible on a large scale. Although UOG is enormously successful, there is surprisingly little known about the effects of this technology on the targeted shale formation and on environmental impacts of oil and gas production at the surface. We examined water samples from both conventional and UOG shale wells to determine the composition, source and fate of organic substances present. Extraction of hydrocarbon from shale plays involves the creation and expansion of fractures through the hydraulic fracturing process. This process involves the injection of large volumes of a water-sand mix treated with organic and inorganic chemicals to assist the process and prop open the fractures created. Formation water from a well in the New Albany Shale that was not hydraulically fractured (no injected chemicals) had total organic carbon (TOC) levels that averaged 8 mg/L, and organic substances that included: long-chain fatty acids, alkanes, polycyclic aromatic hydrocarbons, heterocyclic compounds, alkyl benzenes, and alkyl phenols. In contrast, water from UOG production in the Marcellus Shale had TOC levels as high as 5,500 mg/L, and contained a range of organic chemicals including, solvents, biocides, scale inhibitors, and other organic chemicals at thousands of μg/L for individual compounds. These chemicals and TOC decreased rapidly over the first 20 days of water recovery as injected fluids were recovered, but residual organic compounds (some naturally-occurring) remained up to 250 days after the start of water recovery (TOC 10-30 mg/L). Results show how hydraulic fracturing changes the organic

  7. Relationship between hydrogen gas and butanol production by Clostridium saccharoperbutylacetonicum

    Energy Technology Data Exchange (ETDEWEB)

    Brosseau, J.D.; Yan, J.Y.; Lo, K.V.

    1986-03-01

    Two simultaneous fermentations were performed at 26 degrees C with simultaneous inocula using Clostridium saccharoperbutylacetonicum. Fermentation 1 prevented the gas formed by the biomass from escaping the fermentor while 2 allowed the gas formed to escape. Fermentor 1 provided for the production of butanol, acetone, and ethanol, while when the H/sub 2/ formed was allowed to escape with fermentor 2, neither butanol nor acetone were produced. Ethanol was also formed in both fermentors and began along with the initial growth of biomass and continued until the fermentations were complete. Butanol and acetone production began after biomass growth had reached a maximum and began to subside. The butanol-acetone-ethanol millimolar yields and ratios were 38:1:14 respectively. The fermentor 2 results show that a yield of 2.1 l H/sub 2/, 93 or 370 mmol H/sub 2//mol glucose, was formed only during the growing stage of growth; neither butanol nor acetone were produced; ethanol was formed throughout the fermentation, reaching a yield of 15.2 mmolar. It appears that hydrogen gas is required for butanol production during the resting stage of growth. 16 references.

  8. Effect of ambient-level gas-phase peroxides on foliar injury, growth, and net photosynthesis in Japanese radish (Raphanus sativus)

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xuan, E-mail: xuan66chen@yahoo.co.j [Chinese Research Academy of Environmental Science, No.8, Dayangfang, Anwai, Chaoyang District, Beijing 100012 (China); Aoki, Masatoshi [Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu-shi, Tokyo 183-8509 (Japan); Takami, Akinori [National Institute for Environmental Studies, Onogawa 16-2, Tsukuba-shi, Ibaraki 305-8506 (Japan); Chai Fahe [Chinese Research Academy of Environmental Science, No.8, Dayangfang, Anwai, Chaoyang District, Beijing 100012 (China); Hatakeyama, Shiro [Faculty of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu-shi, Tokyo 183-8509 (Japan)

    2010-05-15

    To investigate the effects of ambient-level gas-phase peroxides concurrent with O{sub 3} on foliar injury, photosynthesis, and biomass in herbaceous plants, we exposed Japanese radish (Raphanus sativus) to clean air, 50 ppb O{sub 3}, 100 ppb O{sub 3}, and 2-3 ppb peroxides + 50 ppb O{sub 3} in outdoor chambers. Compared with exposure to 100 ppb O{sub 3}, exposure to 2-3 ppb peroxides + 50 ppb O{sub 3} induced greater damage in foliar injury, net photosynthetic rates and biomass; the pattern of foliar injury and the cause of net photosynthetic rate reduction also differed from those occurring with O{sub 3} exposure alone. These results indicate for the first time that sub-ppb peroxides + 50 ppb O{sub 3} can cause more severe damage to plants than 100 ppb O{sub 3}, and that not only O{sub 3}, but also peroxides, could be contributing to the herbaceous plant damage and forest decline observed in Japan's air-polluted urban and remote mountains areas. - Ambient-level gas-phase peroxides coexisted with 50 ppb O{sub 3} may contribute to the herbaceous plants damage and forest decline observed in Japan.

  9. The Effects of Rape Residue Mulching on Net Global Warming Potential and Greenhouse Gas Intensity from No-Tillage Paddy Fields

    Science.gov (United States)

    Zhang, Zhi-Sheng; Cao, Cou-Gui; Guo, Li-Jin; Li, Cheng-Fang

    2014-01-01

    A field experiment was conducted to provide a complete greenhouse gas (GHG) accounting for global warming potential (GWP), net GWP, and greenhouse gas intensity (GHGI) from no-tillage (NT) paddy fields with different amounts of oilseed rape residue mulch (0, 3000, 4000, and 6000 kg dry matter (DM) ha−1) during a rice-growing season after 3 years of oilseed rape-rice cultivation. Residue mulching treatments showed significantly more organic carbon (C) density for the 0–20 cm soil layer at harvesting than no residue treatment. During a rice-growing season, residue mulching treatments sequestered significantly more organic C from 687 kg C ha−1 season−1 to 1654 kg C ha−1 season−1 than no residue treatment. Residue mulching significantly increased emissions of CO2 and N2O but decreased CH4 emissions. Residue mulching treatments significantly increased GWP by 9–30% but significantly decreased net GWP by 33–71% and GHGI by 35–72% relative to no residue treatment. These results suggest that agricultural economic viability and GHG mitigation can be achieved simultaneously by residue mulching on NT paddy fields in central China. PMID:25140329

  10. Geological evaluation on productibility of coal seam gas; Coal seam gas no chishitsugakuteki shigen hyoka ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, K. [University of Shizuoka, Shizuoka (Japan). Faculty of Education

    1996-09-01

    Coal seam gas is also called coal bed methane gas, indicating the gas existing in coal beds. The gas is distinguished from the oil field based gas, and also called non-conventional type gas. Its confirmed reserve is estimated to be 24 trillion m {sup 3}, with the trend of its development seen worldwide as utilization of unused resource. For the necessity of cultivating relevant technologies in Japan, this paper considers processes of production, movement, stockpiling, and accumulation of the gas. Its productibility is controlled by thickness of a coal bed, degree of coalification, gas content, permeability, groundwater flow, and deposition structure. Gas generation potential is evaluated by existing conditions of coal and degree of coalification, and methane production by biological origin and thermal origin. Economically viable methane gas is mainly of the latter origin. Evaluating gas reserve potential requires identification of the whole mechanism of adsorption, accumulation and movement of methane gas. The gas is expected of effect on environmental aspects in addition to availability as utilization of unused energy. 5 figs.

  11. Decoupling of greenhouse gas emissions from global agricultural production

    DEFF Research Database (Denmark)

    Bennetzen, Eskild Hohlmann; Smith, Pete; Porter, John Roy

    2016-01-01

    Since 1970 global agricultural production has more than doubled; contributing ~1/4 of total anthropogenic greenhouse gas (GHG) burden in 2010. Food production must increase to feed our growing demands, but to address climate change, GHG emissions must decrease. Using an identity approach, we...... estimate and analyse past trends in GHG emission intensities from global agricultural production and land-use change and project potential future emissions. The novel Kaya-Porter identity framework deconstructs the entity of emissions from a mix of multiple sources of GHGs into attributable elements...... allowing not only a combined analysis of the total level of all emissions jointly with emissions per unit area and emissions per unit product. It also allows us to examine how a change in emissions from a given source contributes to the change in total emissions over time. We show that agricultural...

  12. Energy potential and greenhouse gas emissions from bioenergy cropping systems on marginally productive cropland.

    Directory of Open Access Journals (Sweden)

    Marty R Schmer

    Full Text Available Low-carbon biofuel sources are being developed and evaluated in the United States and Europe to partially offset petroleum transport fuels. Current and potential biofuel production systems were evaluated from a long-term continuous no-tillage corn (Zea mays L. and switchgrass (Panicum virgatum L. field trial under differing harvest strategies and nitrogen (N fertilizer intensities to determine overall environmental sustainability. Corn and switchgrass grown for bioenergy resulted in near-term net greenhouse gas (GHG reductions of -29 to -396 grams of CO2 equivalent emissions per megajoule of ethanol per year as a result of direct soil carbon sequestration and from the adoption of integrated biofuel conversion pathways. Management practices in switchgrass and corn resulted in large variation in petroleum offset potential. Switchgrass, using best management practices produced 3919±117 liters of ethanol per hectare and had 74±2.2 gigajoules of petroleum offsets per hectare which was similar to intensified corn systems (grain and 50% residue harvest under optimal N rates. Co-locating and integrating cellulosic biorefineries with existing dry mill corn grain ethanol facilities improved net energy yields (GJ ha-1 of corn grain ethanol by >70%. A multi-feedstock, landscape approach coupled with an integrated biorefinery would be a viable option to meet growing renewable transportation fuel demands while improving the energy efficiency of first generation biofuels.

  13. Energy potential and greenhouse gas emissions from bioenergy cropping systems on marginally productive cropland.

    Science.gov (United States)

    Schmer, Marty R; Vogel, Kenneth P; Varvel, Gary E; Follett, Ronald F; Mitchell, Robert B; Jin, Virginia L

    2014-01-01

    Low-carbon biofuel sources are being developed and evaluated in the United States and Europe to partially offset petroleum transport fuels. Current and potential biofuel production systems were evaluated from a long-term continuous no-tillage corn (Zea mays L.) and switchgrass (Panicum virgatum L.) field trial under differing harvest strategies and nitrogen (N) fertilizer intensities to determine overall environmental sustainability. Corn and switchgrass grown for bioenergy resulted in near-term net greenhouse gas (GHG) reductions of -29 to -396 grams of CO2 equivalent emissions per megajoule of ethanol per year as a result of direct soil carbon sequestration and from the adoption of integrated biofuel conversion pathways. Management practices in switchgrass and corn resulted in large variation in petroleum offset potential. Switchgrass, using best management practices produced 3919±117 liters of ethanol per hectare and had 74±2.2 gigajoules of petroleum offsets per hectare which was similar to intensified corn systems (grain and 50% residue harvest under optimal N rates). Co-locating and integrating cellulosic biorefineries with existing dry mill corn grain ethanol facilities improved net energy yields (GJ ha-1) of corn grain ethanol by >70%. A multi-feedstock, landscape approach coupled with an integrated biorefinery would be a viable option to meet growing renewable transportation fuel demands while improving the energy efficiency of first generation biofuels.

  14. Optimization and economic evaluation of industrial gas production and combined heat and power generation from gasification of corn stover and distillers grains.

    Science.gov (United States)

    Kumar, Ajay; Demirel, Yasar; Jones, David D; Hanna, Milford A

    2010-05-01

    Thermochemical gasification is one of the most promising technologies for converting biomass into power, fuels and chemicals. The objectives of this study were to maximize the net energy efficiency for biomass gasification, and to estimate the cost of producing industrial gas and combined heat and power (CHP) at a feedrate of 2000kg/h. Aspen Plus-based model for gasification was combined with a CHP generation model, and optimized using corn stover and dried distillers grains with solubles (DDGS) as the biomass feedstocks. The cold gas efficiencies for gas production were 57% and 52%, respectively, for corn stover and DDGS. The selling price of gas was estimated to be $11.49 and $13.08/GJ, respectively, for corn stover and DDGS. For CHP generation, the electrical and net efficiencies were as high as 37% and 88%, respectively, for corn stover and 34% and 78%, respectively, for DDGS. The selling price of electricity was estimated to be $0.1351 and $0.1287/kWh for corn stover and DDGS, respectively. Overall, high net energy efficiencies for gas and CHP production from biomass gasification can be achieved with optimized processing conditions. However, the economical feasibility of these conversion processes will depend on the relative local prices of fossil fuels. Copyright 2009 Elsevier Ltd. All rights reserved.

  15. Mesozooplankton production, grazing and respiration in the Bay of Bengal: Implications for net heterotrophy

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, V.; Ramaiah, N.

    with the Arabian Sea. Contrary to the conventional belief, mesozooplankton grazing impact was up to 83% on primary production (PP). Low PP coupled with very high zooplankton production (70% of PP) along with abundant bacterial production (50% of the PP; Ramaiah et...

  16. Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

    Science.gov (United States)

    Büdel, Burkhard; Williams, Wendy J.; Reichenberger, Hans

    2018-01-01

    Biological soil crusts (biocrusts) are a common element of the Queensland (Australia) dry savannah ecosystem and are composed of cyanobacteria, algae, lichens, bryophytes, fungi and heterotrophic bacteria. Here we report how the CO2 gas exchange of the cyanobacteria-dominated biocrust type from Boodjamulla National Park in the north Queensland Gulf Savannah responds to the pronounced climatic seasonality and on their quality as a carbon sink using a semi-automatic cuvette system. The dominant cyanobacteria are the filamentous species Symplocastrum purpurascens together with Scytonema sp. Metabolic activity was recorded between 1 July 2010 and 30 June 2011, during which CO2 exchange was only evident from November 2010 until mid-April 2011, representative of 23.6 % of the 1-year recording period. In November at the onset of the wet season, the first month (November) and the last month (April) of activity had pronounced respiratory loss of CO2. The metabolic active period accounted for 25 % of the wet season and of that period 48.6 % was net photosynthesis (NP) and 51.4 % dark respiration (DR). During the time of NP, net photosynthetic uptake of CO2 during daylight hours was reduced by 32.6 % due to water supersaturation. In total, the biocrust fixed 229.09 mmol CO2 m-2 yr-1, corresponding to an annual carbon gain of 2.75 g m-2 yr-1. Due to malfunction of the automatic cuvette system, data from September and October 2010 together with some days in November and December 2010 could not be analysed for NP and DR. Based on climatic and gas exchange data from November 2010, an estimated loss of 88 mmol CO2 m-2 was found for the 2 months, resulting in corrected annual rates of 143.1 mmol CO2 m-2 yr-1, equivalent to a carbon gain of 1.7 g m-2 yr-1. The bulk of the net photosynthetic activity occurred above a relative humidity of 42 %, indicating a suitable climatic combination of temperature, water availability and light intensity well above 200 µmol photons m-2 s-1

  17. Characterization of biomass producer gas as fuel for stationary gas engines in combined heat and power production

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper

    2008-01-01

    different measuring methods. Likewise, no particles were detected in the gas. Considerable amounts of NH3 were measured in the produced gas.An analysis of engine operation at varying load has been carried out. Standard emissions, load and efficiency have been measured at varying operating conditions ranging......The aim of this project has been the characterization of biomass producer gas as a fuel for stationary gas engines in heat and power production. More than 3200 hours of gas engine operation, with producer gas as fuel, has been conducted at the biomass gasification combined heat and power (CHP...

  18. Hydrate bearing clayey sediments: Formation and gas production concepts

    KAUST Repository

    Jang, Jaewon

    2016-06-20

    Hydro-thermo-chemo and mechanically coupled processes determine hydrate morphology and control gas production from hydrate-bearing sediments. Force balance, together with mass and energy conservation analyses anchored in published data provide robust asymptotic solutions that reflect governing processes in hydrate systems. Results demonstrate that hydrate segregation in clayey sediments results in a two-material system whereby hydrate lenses are surrounded by hydrate-free water-saturated clay. Hydrate saturation can reach ≈2% by concentrating the excess dissolved gas in the pore water and ≈20% from metabolizable carbon. Higher hydrate saturations are often found in natural sediments and imply methane transport by advection or diffusion processes. Hydrate dissociation is a strongly endothermic event; the available latent heat in a reservoir can sustain significant hydrate dissociation without triggering ice formation during depressurization. The volume of hydrate expands 2-to-4 times upon dissociation or CO2single bondCH4 replacement. Volume expansion can be controlled to maintain lenses open and to create new open mode discontinuities that favor gas recovery. Pore size is the most critical sediment parameter for hydrate formation and gas recovery and is controlled by the smallest grains in a sediment. Therefore any characterization must carefully consider the amount of fines and their associated mineralogy.

  19. Gas Sensing Analysis of Ag-Decorated Graphene for Sulfur Hexafluoride Decomposition Products Based on the Density Functional Theory.

    Science.gov (United States)

    Zhang, Xiaoxing; Huang, Rong; Gui, Yingang; Zeng, Hong

    2016-11-01

    Detection of decomposition products of sulfur hexafluoride (SF₆) is one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, and the occurrence of sudden accidents can be avoided effectively by finding early latent faults. Recently, functionalized graphene, a kind of gas sensing material, has been reported to show good application prospects in the gas sensor field. Therefore, calculations were performed to analyze the gas sensing properties of intrinsic graphene (Int-graphene) and functionalized graphene-based material, Ag-decorated graphene (Ag-graphene), for decomposition products of SF₆, including SO₂F₂, SOF₂, and SO₂, based on density functional theory (DFT). We thoroughly investigated a series of parameters presenting gas-sensing properties of adsorbing process about gas molecule (SO₂F₂, SOF₂, SO₂) and double gas molecules (2SO₂F₂, 2SOF₂, 2SO₂) on Ag-graphene, including adsorption energy, net charge transfer, electronic state density, and the highest and lowest unoccupied molecular orbital. The results showed that the Ag atom significantly enhances the electrochemical reactivity of graphene, reflected in the change of conductivity during the adsorption process. SO₂F₂ and SO₂ gas molecules on Ag-graphene presented chemisorption, and the adsorption strength was SO₂F₂ > SO₂, while SOF₂ absorption on Ag-graphene was physical adsorption. Thus, we concluded that Ag-graphene showed good selectivity and high sensitivity to SO₂F₂. The results can provide a helpful guide in exploring Ag-graphene material in experiments for monitoring the insulation status of SF₆-insulated equipment based on detecting decomposition products of SF₆.

  20. Gas Sensing Analysis of Ag-Decorated Graphene for Sulfur Hexafluoride Decomposition Products Based on the Density Functional Theory

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2016-11-01

    Full Text Available Detection of decomposition products of sulfur hexafluoride (SF6 is one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, and the occurrence of sudden accidents can be avoided effectively by finding early latent faults. Recently, functionalized graphene, a kind of gas sensing material, has been reported to show good application prospects in the gas sensor field. Therefore, calculations were performed to analyze the gas sensing properties of intrinsic graphene (Int-graphene and functionalized graphene-based material, Ag-decorated graphene (Ag-graphene, for decomposition products of SF6, including SO2F2, SOF2, and SO2, based on density functional theory (DFT. We thoroughly investigated a series of parameters presenting gas-sensing properties of adsorbing process about gas molecule (SO2F2, SOF2, SO2 and double gas molecules (2SO2F2, 2SOF2, 2SO2 on Ag-graphene, including adsorption energy, net charge transfer, electronic state density, and the highest and lowest unoccupied molecular orbital. The results showed that the Ag atom significantly enhances the electrochemical reactivity of graphene, reflected in the change of conductivity during the adsorption process. SO2F2 and SO2 gas molecules on Ag-graphene presented chemisorption, and the adsorption strength was SO2F2 > SO2, while SOF2 absorption on Ag-graphene was physical adsorption. Thus, we concluded that Ag-graphene showed good selectivity and high sensitivity to SO2F2. The results can provide a helpful guide in exploring Ag-graphene material in experiments for monitoring the insulation status of SF6-insulated equipment based on detecting decomposition products of SF6.

  1. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  2. Quantitative Assessment of the Human Appropriation of Net Primary Production (HANPP in the Coastal Areas of Jiangsu, China

    Directory of Open Access Journals (Sweden)

    Fangyi Zhang

    2015-11-01

    Full Text Available Global increases in population and consumption have raised concerns regarding the sustainability of the current and future use of natural resources. The human appropriation of net primary production (HANPP provides a useful measure for determining human-derived alterations in the amount of biomass that is available in ecosystems each year. HANPP was calculated based on vegetation modelling, agricultural statistics, and remote sensing data on land use and land cover to assess the human impacts on ecosystems in the coastal areas of Jiangsu, China. The results showed that HANPP increased from 332 g·C/m2/year in 2000 to 442 g·C/m2/year in 2010, with an average annual increase of 2.9%. The proportion of appropriated net primary production increased from 50.3% to 71.0% of NPPpot, mainly driven by HANPPharv (harvested NPP with an increase from 45.2% to 61.3% of NPPpot. Additionally, the spatial variation in average HANPP was striking among counties in the observed period with the lowest and highest values of 21.8% and 63.8% of NPPpot, respectively. Further analysis showed that observed levels of HANPP are high due to a high level of biomass harvest from cropland and the increases in fertilizer use, farmland irrigation rate and population and economic growth explain the trends in HANPP in the coastal areas of Jiangsu.

  3. Production of bioplastics and hydrogen gas by photosynthetic microorganisms

    Science.gov (United States)

    Yasuo, Asada; Masato, Miyake; Jun, Miyake

    1998-03-01

    Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium, Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilic Synechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes from Alcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted. In vitro and in vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture of Rhodobacter and Clostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium, Rhodobacter sphaeroides RV. A mutant acquired by

  4. Catalytic Production of Ethanol from Biomass-Derived Synthesis Gas

    Energy Technology Data Exchange (ETDEWEB)

    Trewyn, Brian G. [Colorado School of Mines, Golden, CO (United States); Smith, Ryan G. [Iowa State Univ., Ames, IA (United States)

    2016-06-01

    Heterogeneous catalysts have been developed for the conversion of biomass-derived synthetic gas (syngas) to ethanol. The objectives of this project were to develop a clean synthesis gas from biomass and develop robust catalysts with high selectivity and lifetime for C2 oxygenate production from biomass-derived syngas and surrogate syngas. During the timeframe for this project, we have made research progress on the four tasks: (1) Produce clean bio-oil generated from biomass, such as corn stover or switchgrass, by using fast pyrolysis system, (2) Produce clean, high pressure synthetic gas (syngas: carbon monoxide, CO, and hydrogen, H2) from bio-oil generated from biomass by gasification, (3) Develop and characterize mesoporous mixed oxide-supported metal catalysts for the selective production of ethanol and other alcohols, such as butanol, from synthesis gas, and (4) Design and build a laboratory scale synthesis gas to ethanol reactor system evaluation of the process. In this final report, detailed explanations of the research challenges associated with this project are given. Progress of the syngas production from various biomass feedstocks and catalyst synthesis for upgrading the syngas to C2-oxygenates is included. Reaction properties of the catalyst systems under different reaction conditions and different reactor set-ups are also presented and discussed. Specifically, the development and application of mesoporous silica and mesoporous carbon supports with rhodium nanoparticle catalysts and rhodium nanoparticle with manganese catalysts are described along with the significant material characterizations we completed. In addition to the synthesis and characterization, we described the activity and selectivity of catalysts in our micro-tubular reactor (small scale) and fixed bed reactor (larger scale). After years of hard work, we are proud of the work done on this project, and do believe that this work will provide a solid

  5. Coupling above and below ground gas measurements to understand greenhouse gas production in the soil profile

    Science.gov (United States)

    Nickerson, Nick; Creelman, Chance

    2016-04-01

    Natural and anthropogenic changes in climate have the potential to significantly affect the Earth's natural greenhouse gas balances. To understand how these climatic changes will manifest in a complex biological, chemical and physical system, a process-based understanding of the production and consumption of greenhouse gases in soils is critical. Commonly, both chamber methods and gradient-based approaches are used to estimate greenhouse gas flux from the soil to the atmosphere. Each approach offers benefits, but not surprisingly, comes with a list of drawbacks. Chambers are easily deployed on the surface without significant disturbance to the soil, and can be easily spatially replicated. However the high costs of automated chamber systems and the inability to partition fluxes by depth are potential downfalls. The gradient method requires a good deal of disturbance for installation, however it also offers users spatiotemporally resolved flux estimates at a reasonable price point. Researchers widely recognize that the main drawback of the gradient approach is the requirement to estimate diffusivity using empirical models based on studies of specific soils or soil types. These diffusivity estimates can often be off by several orders of magnitude, yielding poor flux estimates. Employing chamber and gradient methods in unison allows for in-situ estimation of the diffusion coefficient, and therefore improves gradient-based estimates of flux. A dual-method approach yields more robust information on the temporal dynamics and depth distribution of greenhouse gas production and consumption in the soil profile. Here we present a mathematical optimization framework that allows these complimentary measurement techniques to yield more robust information than a single technique alone. We then focus on how it can be used to improve the process-based understanding of greenhouse gas production in the soil profile.

  6. Mitigating the greenhouse gas balance of ruminant production systems through carbon sequestration in grasslands.

    Science.gov (United States)

    Soussana, J F; Tallec, T; Blanfort, V

    2010-03-01

    Soil carbon sequestration (enhanced sinks) is the mechanism responsible for most of the greenhouse gas (GHG) mitigation potential in the agriculture sector. Carbon sequestration in grasslands can be determined directly by measuring changes in soil organic carbon (SOC) stocks and indirectly by measuring the net balance of C fluxes. A literature search shows that grassland C sequestration reaches on average 5 ± 30 g C/m2 per year according to inventories of SOC stocks and -231 and 77 g C/m2 per year for drained organic and mineral soils, respectively, according to C flux balance. Off-site C sequestration occurs whenever more manure C is produced by than returned to a grassland plot. The sum of on- and off-site C sequestration reaches 129, 98 and 71 g C/m2 per year for grazed, cut and mixed European grasslands on mineral soils, respectively, however with high uncertainty. A range of management practices reduce C losses and increase C sequestration: (i) avoiding soil tillage and the conversion of grasslands to arable use, (ii) moderately intensifying nutrient-poor permanent grasslands, (iii) using light grazing instead of heavy grazing, (iv) increasing the duration of grass leys; (v) converting grass leys to grass-legume mixtures or to permanent grasslands. With nine European sites, direct emissions of N2O from soil and of CH4 from enteric fermentation at grazing, expressed in CO2 equivalents, compensated 10% and 34% of the on-site grassland C sequestration, respectively. Digestion inside the barn of the harvested herbage leads to further emissions of CH4 and N2O by the production systems, which were estimated at 130 g CO2 equivalents/m2 per year. The net balance of on- and off-site C sequestration, CH4 and N2O emissions reached 38 g CO2 equivalents/m2 per year, indicating a non-significant net sink activity. This net balance was, however, negative for intensively managed cut sites indicating a source to the atmosphere. In conclusion, this review confirms that

  7. Effect of tensides on gas production in an anaerobic filter

    Energy Technology Data Exchange (ETDEWEB)

    Levonen-Munoz, E.; Malkki, Y.

    1979-02-01

    The effect of the addition of tensides on methane production was studied using a nonionic tenside, Tween 20 (poly(oxyethylene sorbitan monolaurate)), and an anionic tenside, sodium dodecyl sulfate (SDS). Tween 20 increased the gas formation, especially at 0.001 and 0.01% concentration. The decomposition of SDS nullified its effect as a tenside. Two mechanisms could explain the promoting effect of Tween 20. One is the enhanced separation of gas bubbles from the surface of the cells because of diminished interfacial tension and thus improving the mass transfer. The other is a possible activating effect of the tenside on membrane functions. At higher concentrations both tensides increased the volatile acid content of the effluent, indicating reduced synthesis of cell material. (JSR)

  8. Net primary productivity of subalpine meadows in Yosemite National Park in relation to climate variability

    Science.gov (United States)

    Peggy E. Moore; Jan W. van Wagtendonk; Julie L. Yee; Mitchel P. McClaran; David N. Cole; Neil K. McDougald; Matthew L. Brooks

    2013-01-01

    Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate....

  9. Net soil respiration and greenhouse gas balance along a sequence of forest disturbance to smallholder rubber and oil palm plantations in Sumatra

    Science.gov (United States)

    Khusyu Aini, Fitri; Hergoualc'h, Kristell; Smith, Jo; Verchot, Louis; Martius, Christopher

    2017-04-01

    The rapid increase in demand for land to establish oil palm and rubber plantations has led to the conversion of forests, with potential impacts on greenhouse gas emissions and on climate change. This study evaluates the net greenhouse gas balance following forest change to other land uses, i.e. one year rubber plantation, twenty-year rubber plantation and eight year oil palm plantation on Sumatran mineral soils. None of the plantations had ever been fertilized previously. During this study they were fertilized to provide nitrogen at the recommended rate used by farmers (33.3 kg N ha-1 y-1). The ecosystem stores carbon in litterfall, standing litter biomass (undergrowth vegetation, leaves, twigs, litter on the soil surface), soil organic matter, root biomass, and standing tree biomass. It releases carbon to the atmosphere through soil respiration fluxes, negative values indicating that carbon is stored by the land use change and positive values indicating emissions to the atmosphere. Net soil respiration was assessed using a mass balance approach: standing litter and tree biomass were measured once; the rate of carbon accumulation from standing litter and tree biomass was calculated by dividing the stock by the age of plantation or the time since logging started in the disturbed forest. The carbon accumulation in standing litter, tree biomass in the forest and soil organic matter for all land-uses was estimated from available in the literature. Root biomass for each land-use system was calculated using the root:shoot ratio. The net soil respiration of carbon dioxide from the forest, disturbed forest, one year rubber plantation, twenty-year rubber plantation and oil palm plantation were calculated to be -6 (± 5), 12 (± 6), 11 (± 15), 10 (± 5), 39 (± 7) Mg ha-1 y-1, respectively. Soil nitrous oxide, methane and litterfall were measured for 14 months and respiration fluxes were measured for 5 months across land uses and different seasons. The measured emissions of

  10. Storage sizing for embedding of local gas production in a micro gas grid

    Science.gov (United States)

    Alkano, D.; Nefkens, W. J.; Scherpen, J. M. A.; Volkerts, M.

    2014-12-01

    In this paper we study the optimal control of a micro grid of biogas producers. The paper considers the possibility to have a local storage device for each producer, who partly consumes his own production, i.e. prosumer. In addition, connected prosumers can sell stored gas to create revenue from it. An optimization model is employed to derive the size of storage device and to provide a pricing mechanism in an effort to value the stored gas. Taking into account physical grid constraints, the model is constructed in a centralized scheme of model predictive control. Case studies show that there is a relation between the demand and price profiles in terms of peaks and lows. The price profiles generally follow each other. The case studies are employed as well to to study the impacts of model parameters on deriving the storage size.

  11. Storage sizing for embedding of local gas production in a micro gas grid

    Directory of Open Access Journals (Sweden)

    Alkano D.

    2014-01-01

    Full Text Available In this paper we study the optimal control of a micro grid of biogas producers. The paper considers the possibility to have a local storage device for each producer, who partly consumes his own production, i.e. prosumer. In addition, connected prosumers can sell stored gas to create revenue from it. An optimization model is employed to derive the size of storage device and to provide a pricing mechanism in an effort to value the stored gas. Taking into account physical grid constraints, the model is constructed in a centralized scheme of model predictive control. Case studies show that there is a relation between the demand and price profiles in terms of peaks and lows. The price profiles generally follow each other. The case studies are employed as well to to study the impacts of model parameters on deriving the storage size.

  12. Emissions of Volatile Organic Compounds (VOCs) Associated with Natural Gas Production in the Uintah Basin, Utah

    Science.gov (United States)

    Warneke, C.; Geiger, F.; Zahn, A.; Graus, M.; De Gouw, J. A.; Gilman, J. B.; Lerner, B. M.; Roberts, J. M.; Edwards, P. M.; Dube, W. P.; Brown, S. S.; Peischl, J.; Ryerson, T. B.; Williams, E. J.; Petron, G.; Kofler, J.; Sweeney, C.; Karion, A.; Dlugokencky, E. J.

    2012-12-01

    Technological advances such as hydraulic fracturing have led to a rapid increase in the production of natural gas from several basins in the Rocky Mountain West, including the Denver-Julesburg basin in Colorado, the Uintah basin in Utah and the Upper Green River basin in Wyoming. There are significant concerns about the impact of natural gas production on the atmosphere, including (1) emissions of methane, which determine the net climate impact of this energy source, (2) emissions of reactive hydrocarbons and nitrogen oxides, and their contribution to photochemical ozone formation, and (3) emissions of air toxics with direct health effects. The Energy & Environment - Uintah Basin Wintertime Ozone Study (UBWOS) in 2012 was focused on addressing these issues. During UBWOS, measurements of volatile organic compounds (VOCs) were made using proton-transfer-reaction mass spectrometry (PTR-MS) instruments from a ground site and a mobile laboratory. Measurements at the ground site showed mixing ratios of VOCs related to oil and gas extraction were greatly enhanced in the Uintah basin, including several days long periods of elevated mixing ratios and concentrated short term plumes. Diurnal variations were observed with large mixing ratios during the night caused by low nighttime mixing heights and a shift in wind direction during the day. The mobile laboratory sampled a wide variety of individual parts of the gas production infrastructure including active gas wells and various processing plants. Included in those point sources was a new well that was sampled by the mobile laboratory 11 times within two weeks. This new well was previously hydraulically fractured and had an active flow-back pond. Very high mixing ratios of aromatics were observed close to the flow-back pond. The measurements of the mobile laboratory are used to determine the source composition of the individual point sources and those are compared to the VOC enhancement ratios observed at the ground site. The

  13. Trash to Gas: Converting Space Waste into Useful Supply Products

    Science.gov (United States)

    Tsoras, Alexandra

    2013-01-01

    The cost of sending mass into space with current propulsion technology is very expensive, making every item a crucial element of the space mission. It is essential that all materials be used to their fullest potential. Items like food, packaging, clothing, paper towels, gloves, etc., normally become trash and take up space after use. These waste materials are currently either burned up upon reentry in earth's atmosphere or sent on cargo return vehicles back to earth: a very wasteful method. The purpose of this project was to utilize these materials and create useful products like water and methane gas, which is used for rocket fuel, to further supply a deep space mission. The system used was a thermal degradation reactor with the configuration of a down-draft gasifier. The reactor was loaded with approximately 100g of trash simulant and heated with two external ceramic heaters with separate temperature control in order to create pyrolysis and gasification in one zone and incineration iri a second zone simultaneously. Trash was loaded into the top half of the reactor to undergo pyrolysis while the downdraft gas experienced gasification or incineration to treat tars and maximize the production of carbon dioxide. Minor products included carbon monoxide, methane, and other hydrocarbons. The carbon dioxide produced can be sent to a Sabatier reactor to convert the gas into methane, which can be used as rocket propellant. In order to maximize the carbon dioxide and useful gases produced, and minimize the unwanted tars and leftover ashen material, multiple experiments were performed with altered parameters such as differing temperatures, flow rates, and location of inlet air flow. According to the data received from these experiments, the process will be further scaled up and optimized to ultimately create a system that reduces trash buildup while at the same time providing enough useful gases to potentially fill a methane tank that could fuel a lunar ascent vehicle or

  14. Temperature and organic matter controls on hyporheic greenhouse gas production

    Science.gov (United States)

    Comer-Warner, S.; Romeijn, P.; Krause, S.; Hannah, D. M.; Gooddy, D.

    2016-12-01

    The region of groundwater and surface water mixing, known as the hyporheic zone, has recently attracted interest as an area of greenhouse gas (GHG) production. Although high concentrations of GHG have been found in these environments, the drivers of hyporheic GHG production remain poorly understood. Here we present the results of a microcosm incubation experiment, designed to determine the effect of multiple environmental parameters on GHG production. Three sediment types, representing a gradient of organic matter contents, from two contrasting UK lowland rivers (sandstone and chalk), were incubated for 29 hours. Experiments were performed at five temperature treatments between 5 and 25°C, and the microbial metabolism of each microcosm was determined using the smart tracer Resazurin. Headspace concentrations of carbon dioxide, methane and nitrous oxide were measured to determine the effect of these environmental parameters on GHG production, and establish their roles as drivers of GHG production in the hyporheic zone. Our results indicate strong temperature controls of GHG production, overlapping with the observed impacts of varying organic matter content of different sediments. Experimental findings indicate that increased hyporheic temperatures during increasing baseflow and drought conditions may significantly enhance sediment respiration, and thus, GHG emissions from the streambed interface. This research advances understanding of drivers of whole stream carbon and nitrogen budgets, as well as the role of groundwater-surface water interfaces in GHG emissions, and allows the interaction of these controls to be assessed.

  15. Greenhouse gas emissions from aluminium production - a life cycle approach

    Energy Technology Data Exchange (ETDEWEB)

    Norgate, T.E.; Rankin, W.J. [CSIRO Minerals, Clayton South, Victoria (Australia)

    2001-07-01

    A life cycle assessment (LCA) of aluminium metal production was carried out from bauxite mining through aluminium smelting on three process route, namely (1) the Bayer process for alumina production; (2) the Hall-Heroult process for aluminium production; and (3) the carbothermic reduction process for aluminium production. Some developing processes associated with these processes, such as the drained cathodes, inert cathodes and low temperature electrolytes for the Hall-Heroult process, and the direct and solvent-based processing options for carbothermic reduction of alumina and also of dross, were also included in the study. A 'cradle to gate' LCA of the various technological processes were found to offer the possibility of significant reduction in GHG emissions for primary aluminium production. However, none of these developments have been implemented commercially, hence such reductions may be expected in the longer, rather than the shorter, term. In the immediate future, GHG emissions from primary aluminium production are more likely to come from energy conservation measures than from technological developments. Changing from coal-based electricity to natural gas-based or hydroelectric-based electricity should result in substantial reductions, particularly if such changes are accompanied by increases in electricity generation efficiency. 11 refs., 2 tabs., 4 figs.

  16. MISR Level 3 Cloud Motion Vector monthly Product in netCDF format V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 Monthly Cloud Motion Vector Product contains retrievals of cloud motion determined by geometrically triangulating the position and motion of cloud...

  17. MISR Level 3 Cloud Motion Vector yearly Product in netCDF format V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Level 3 Yearly Cloud Motion Vector Product contains retrievals of cloud motion determined by geometrically triangulating the position and motion of cloud...

  18. Excess heat production of future net zero energy buildings within district heating areas in Denmark

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Möller, Bernd

    2012-01-01

    buildings in Denmark are connected to electricity grids and around half are connected to districtheating (DH) systems. Connecting buildings to larger energy systems enables them to send and receive energy from these systems. This paper’s objective is to examine how excess heat production from NZEBs...... excess heat production from solar thermal collectors. The main findings are that the excess heat from NZEBs can benefit DH systems by decreasing the production from production units utilizing combustible fuels. In DH areas where the heat demand in summer months is already covered by renewable energy......Denmark’s long-term energy goal is to develop an energy system solely based on renewable energy sources by 2050. To reach this goal, energy savings in buildings is essential. Therefore, the focus on energy efficient measures in buildings and netzeroenergybuildings (NZEBs) has increased. Most...

  19. ISLSCP II GPPDI, Net Primary Productivity (NPP) Class B Point Data

    Data.gov (United States)

    National Aeronautics and Space Administration — The Global Primary Production Data Initiative (GPPDI) was set up as a Focus 1 activity of the IGBP Data and Information System, a coordinated international program...

  20. ISLSCP II GPPDI, Net Primary Productivity (NPP) Class B Point Data

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Global Primary Production Data Initiative (GPPDI) was set up as a Focus 1 activity of the IGBP Data and Information System, a coordinated international...

  1. Net mineralization of N at deeper soil depths as a potential mechanism for sustained forest production under elevated [CO2

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, Colleen M [ORNL; Hooker, Toby [Utah State University (USU); Classen, Aimee T [University of Tennessee, Knoxville (UTK); Norby, Richard J [ORNL

    2011-01-01

    Elevated atmospheric [CO2] is projected to increase forest production, which could increase ecosystem carbon (C) storage. However, sustained forest production will depend on the nutrient balance of the forested ecosystem. Our aim was to examine the causes and consequences of increased fine-root production and mortality throughout the soil profile under elevated CO2 with respect to potential gross nitrogen (N) cycling rates. Our study was conducted in a CO2-enriched sweetgum (Liquidambar styraciflua L.) plantation in Oak Ridge, TN, USA. We used isotope pool dilution methodology to measure potential gross N cycling rates in laboratory incubations of soil from four depth increments to 60 cm. Our objectives were two-fold: (1) determine whether N is available for root acquisition in deeper soil, and (2) determine whether increased inputs of labile C from greater fine-root mortality at depth under elevated [CO2] had altered N cycling rates. While gross N fluxes declined with soil depth, we found that N is potentially available for roots to access, especially below 15 cm depth where microbial consumption of mineral N was reduced. Overall, up to 60% of potential gross N mineralization, and 100% of potential net N mineralization, occurred below 15-cm depth at this site. This finding was supported by in situ measurements from ion-exchange resins, where total inorganic N availability at 55 cm depth was equal to or greater than N availability at 15 cm depth. While it is likely that trees grown under elevated [CO2] are accessing a larger pool of inorganic N by mining deeper soil, we found no effect of elevated [CO2] on potential gross or net N cycling rates. Thus, increased root exploration of the soil volume under elevated [CO2] may be more important than changes in potential gross N cycling rates in sustaining forest responses to rising atmospheric CO2.

  2. The effect of cannibalism intensity on the net primary production and the dynamics of trophic links in the aquatic ecosystem

    Science.gov (United States)

    Sirobokova, I.; Pechurkin, N.

    The aim of the work was to construct a mathematical model of the effect of cannibalism intensity on the dynamic behavior and functional characteristics of simple aquatic ecosystems. A mathematical model of an aquatic ecosystem has been constructed, with the following principal trophic links: limiting nutrient concentration, producers (phytoplankton), predators of the first order, and predators of the second order. The model takes into account the age structure of the second-order predator and includes two age groups (the young and adults). The adult predators of the second order are cannibals feeding on both first-order predators and their own young, which consume phytoplankton. The model was used to investigate the effect of cannibalism intensity on the net primary production and the dynamics of trophic links in the aquatic ecosystem characterized by cannibalism at the upper trophic level or by the emergence of a third-order predator in the system. It has been found that when cannibalism increases above a certain level, the concentrations of both adults and the young of the 2nd-order predators decrease. At the same time, the concentrations of the 1st-order predators and of nutrients increase, while the biomass of producers decreases. When the cannibalism intensity is low, the net primary production of the system increases to a certain level with the increase in cannibalism intensity and drops sharply when the level of consumption of the young is high. The emergence of the 3rd-order predator in the system leads to a change in the dynamics of links in conformity with the "bottom-up" and "top-down" control. Thus, cannibalism of a certain magnitude can lead to an increase in integrated parameters of aquatic ecosystems: the amount of energy used by the ecosystem and the productivity in the photosynthesis link.

  3. Grassland and cropland net ecosystem production of the U.S. Great Plains: Regression tree model development and comparative analysis

    Science.gov (United States)

    Wylie, Bruce K.; Howard, Daniel; Dahal, Devendra; Gilmanov, Tagir; Ji, Lei; Zhang, Li; Smith, Kelcy

    2016-01-01

    This paper presents the methodology and results of two ecological-based net ecosystem production (NEP) regression tree models capable of up scaling measurements made at various flux tower sites throughout the U.S. Great Plains. Separate grassland and cropland NEP regression tree models were trained using various remote sensing data and other biogeophysical data, along with 15 flux towers contributing to the grassland model and 15 flux towers for the cropland model. The models yielded weekly mean daily grassland and cropland NEP maps of the U.S. Great Plains at 250 m resolution for 2000–2008. The grassland and cropland NEP maps were spatially summarized and statistically compared. The results of this study indicate that grassland and cropland ecosystems generally performed as weak net carbon (C) sinks, absorbing more C from the atmosphere than they released from 2000 to 2008. Grasslands demonstrated higher carbon sink potential (139 g C·m−2·year−1) than non-irrigated croplands. A closer look into the weekly time series reveals the C fluctuation through time and space for each land cover type.

  4. Performance of free-range chickens reared in production modules enriched with shade net and perches

    Directory of Open Access Journals (Sweden)

    MJB Santos

    2014-03-01

    Full Text Available An experiment was carried out to evaluate the effect of environmental enrichment in a free-range chicken production system on live performance as a function of microclimate, physiological parameters, and performance parameters. Four production modules were divided into four pens with 10 birds each, totaling 60 birds. The following treatments were applied: access to a paddock (TEST, access to a paddock with perches (PER, access to a paddock with artificial shade (SHA, and access to the paddock with perches and artificial shade (PESH. The PESH production module presented the best globe temperature (Tbg,ºC and enthalpy (h, kJ/kg, and thereby, the best thermal environmental conditions, which ensured the longest permanence time of the birds in the paddock. The SHA and PESH modules promoted the lowest respiratory rate and shank and comb temperatures. Live performance was influenced by the presence of environmental enrichment (modules SHA and PESH, with the highest live weight (LW and weight gain (WG and the lowest feed conversion ratio (FCR and metabolizable energy intake (MEI. Parts yield, such as giblets, were not influenced by production modules, except for PESH, which promoted higher offal weight. In general, chickens reared in enriched production modules presented greatest performance and comfort results and were considered close to optimal rearing conditions.

  5. An Evaluation of the NetBeans Module System as a Product line Implementation Technology

    DEFF Research Database (Denmark)

    Mærsk-Møller, Hans Martin; Jørgensen, Bo Nørregaard

    2011-01-01

    Variability is one of the key concepts of software reuse in software product line engineering (SPLE). Rich client platforms (RCPs) have been designed to facilitate development of modern client applications. They facilitate this with concepts, structures and pre-made functionality which support...... the development and conceptualization of flexible and modular applications. These characteristics make them interesting in the context of SPLE. Despite the fact that modularity, extensibility and flexibility are characteristics, which in general are even more important to software product lines (SPLs) than...

  6. Air quality concerns of unconventional oil and natural gas production.

    Science.gov (United States)

    Field, R A; Soltis, J; Murphy, S

    2014-05-01

    Increased use of hydraulic fracturing ("fracking") in unconventional oil and natural gas (O & NG) development from coal, sandstone, and shale deposits in the United States (US) has created environmental concerns over water and air quality impacts. In this perspective we focus on how the production of unconventional O & NG affects air quality. We pay particular attention to shale gas as this type of development has transformed natural gas production in the US and is set to become important in the rest of the world. A variety of potential emission sources can be spread over tens of thousands of acres of a production area and this complicates assessment of local and regional air quality impacts. We outline upstream activities including drilling, completion and production. After contrasting the context for development activities in the US and Europe we explore the use of inventories for determining air emissions. Location and scale of analysis is important, as O & NG production emissions in some US basins account for nearly 100% of the pollution burden, whereas in other basins these activities make up less than 10% of total air emissions. While emission inventories are beneficial to quantifying air emissions from a particular source category, they do have limitations when determining air quality impacts from a large area. Air monitoring is essential, not only to validate inventories, but also to measure impacts. We describe the use of measurements, including ground-based mobile monitoring, network stations, airborne, and satellite platforms for measuring air quality impacts. We identify nitrogen oxides, volatile organic compounds (VOC), ozone, hazardous air pollutants (HAP), and methane as pollutants of concern related to O & NG activities. These pollutants can contribute to air quality concerns and they may be regulated in ambient air, due to human health or climate forcing concerns. Close to well pads, emissions are concentrated and exposure to a wide range of

  7. Relationships among net primary productivity, nutrients and climate in tropical rain forest: A pan-tropical analysis

    Science.gov (United States)

    Cleveland, Cory C.; Townsend, Alan R.; Taylor, Philip; Alvarez-Clare, Silvia; Bustamante, Mercedes M.C.; Chuyong, George; Dobrowski, Solomon Z.; Grierson, Pauline; Harms, Kyle E.; Houlton, Benjamin Z.; Marklein, Alison; Parton, William; Porder, Stephen; Reed, Sasha C.; Sierra, Carlos A.; Silver, Whendee L.; Tanner, Edmund V.J.; Wieder, William R.

    2011-01-01

    Tropical rain forests play a dominant role in global biosphere-atmosphere CO2 exchange. Although climate and nutrient availability regulate net primary production (NPP) and decomposition in all terrestrial ecosystems, the nature and extent of such controls in tropical forests remain poorly resolved. We conducted a meta-analysis of carbon-nutrient-climate relationships in 113 sites across the tropical forest biome. Our analyses showed that mean annual temperature was the strongest predictor of aboveground NPP (ANPP) across all tropical forests, but this relationship was driven by distinct temperature differences between upland and lowland forests. Within lowland forests (forests, but more importantly, underscores the need for a series of large-scale nutrient manipulations – especially in lowland forests – to elucidate the most important nutrient interactions and controls.

  8. Weather and Management Effects over Nine Years of Net Ecosystem Direct Greenhouse Gas Emissions from a Cropping System in the Red River Valley, Manitoba

    Science.gov (United States)

    Tenuta, M.; Amiro, B. D.

    2014-12-01

    Variation in weather and crop management practices strongly determines direct greenhouse gas emissions (CO2 and N2O) from agricultural crop land. Thus a long-term study was established to relate weather and management variations to direct emissions in the Northern Great Plains of Canada. Continuously emission determinations of CO2 and N2O were established at the Trace Gas Manitoba (TGAS-MAN) Long Term Greenhouse Gas Monitoring Site at Glenlea, Manitoba, using the flux gradient micrometeorlogical technique with a tunable diode laser analyzer. The soil is poorly drained clay in the Red River Valley. The field experiment consisted of four 4-hectare plots planted to corn in 2006 and faba bean in 2007. In 2008, grass-alfalfa forage was introduced to two plots (annual - perennial) and grown until 2011 whereas the other two plots (annual) were planted to annual crops: spring wheat, rapeseed, barley and spring wheat in 2008, 2009, 2010 and 2011, respectively. In late September of 2011 the grass-alfalfa forage was killed and in 2012, 2013 and 2014 all four plots were planted with corn, soybean and spring wheat, respectively. Management decisions increased emissions such as fertilizer N addition, and hay, straw and silage crop removal greatly increased emissions while choosing legume grain and perennial crops reduced emissions. Weather variation affecting seasonal and daily soil moisture, length of spring freeze-thaw period, and crop yield served to increase or decrease emissions. The variation in management and weather will be discussed in regards to impact on net emissions over the nine year study and answer if development of greenhouse gas neutral cropping systems is possible.

  9. Analysis of spatial and temporal patterns of aboveground net primary productivity in the Eurasian steppe region from 1982 to 2013.

    Science.gov (United States)

    Jiao, Cuicui; Yu, Guirui; Ge, Jianping; Chen, Xi; Zhang, Chi; He, Nianpeng; Chen, Zhi; Hu, Zhongmin

    2017-07-01

    To explore the importance of the Eurasian steppe region (EASR) in global carbon cycling, we analyzed the spatiotemporal dynamics of the aboveground net primary productivity (ANPP) of the entire EASR from 1982 to 2013. The ANPP in the EASR was estimated from the Integrated ANPPNDVI model, which is an empirical model developed based on field-observed ANPP and long-term normalized difference vegetation index (NDVI) data. The optimal composite period of NDVI data was identified by considering spatial heterogeneities across the study area in the Integrated ANPPNDVI model. EASR's ANPP had apparent zonal patterns along hydrothermal gradients, and the mean annual value was 43.78 g C m(-2) yr(-1), which was lower than the global grasslands average. Compared to other important natural grasslands, EASR's ANPP was lower than the North American, South American, and African grasslands. The total aboveground net primary productivity (TANPP) was found to be 378.97 Tg C yr(-1), which accounted for 8.18%-36.03% of the TANPP for all grasslands. In addition, EASR's TANPP was higher than that of the grasslands in North America, South America, and Africa. The EASR's TANPP increased in a fluctuating manner throughout the entire period of 1982-2013. The increasing trend was greater than that for North American and South American and was lower than that for African grasslands over the same period. The years 1995 and 2007 were two turning points at which trends in EASR's TANPP significantly changed. Our analysis demonstrated that the EASR has been playing a substantial and progressively more important role in global carbon sequestration. In addition, in the development of empirical NDVI-based ANPP models, the early-middle growing season averaged NDVI, the middle-late growing season averaged NDVI and the annual maximum NDVI are recommended for use for semi-humid regions, semi-arid regions, and desert vegetation in semi-arid regions, respectively.

  10. Hydro-geomechanical behaviour of gas-hydrate bearing soils during gas production through depressurization and CO2 injection

    Science.gov (United States)

    Deusner, C.; Gupta, S.; Kossel, E.; Bigalke, N.; Haeckel, M.

    2015-12-01

    Results from recent field trials suggest that natural gas could be produced from marine gas hydrate reservoirs at compatible yields and rates. It appears, from a current perspective, that gas production would essentially be based on depressurization and, when facing suitable conditions, be assisted by local thermal stimulation or gas hydrate conversion after injection of CO2-rich fluids. Both field trials, onshore in the Alaska permafrost and in the Nankai Trough offshore Japan, were accompanied by different technical issues, the most striking problems resulting from un-predicted geomechanical behaviour, sediment destabilization and catastrophic sand production. So far, there is a lack of experimental data which could help to understand relevant mechanisms and triggers for potential soil failure in gas hydrate production, to guide model development for simulation of soil behaviour in large-scale production, and to identify processes which drive or, further, mitigate sand production. We use high-pressure flow-through systems in combination with different online and in situ monitoring tools (e.g. Raman microscopy, MRI) to simulate relevant gas hydrate production scenarios. Key components for soil mechanical studies are triaxial systems with ERT (Electric resistivity tomography) and high-resolution local strain analysis. Sand production control and management is studied in a novel hollow-cylinder-type triaxial setup with a miniaturized borehole which allows fluid and particle transport at different fluid injection and flow conditions. Further, the development of a large-scale high-pressure flow-through triaxial test system equipped with μ-CT is ongoing. We will present results from high-pressure flow-through experiments on gas production through depressurization and injection of CO2-rich fluids. Experimental data are used to develop and parametrize numerical models which can simulate coupled process dynamics during gas-hydrate formation and gas production.

  11. Reduction of Net Sulfide Production Rate by Nitrate in Wastewater Bioreactors. Kinetics and Changes in the Microbial Community

    DEFF Research Database (Denmark)

    Villahermosa, Desiree; Corzo, Alfonso; Gonzalez, J M

    2013-01-01

    Nitrate addition stimulated sulfide oxidation by increasing the activity of nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), decreasing the concentration of dissolved H2S in the water phase and, consequently, its release to the atmosphere of a pilot-scale anaerobic bioreactor. The effect...... of four different concentrations of nitrate (0.12, 0.24, 0.50, and 1.00 mM) was investigated for a period of 3 days in relation to sulfide concentration in two bioreactors set up at Guadalete wastewater treatment plant (Jerez de la Frontera, Spain). Physicochemical variables were measured in water and air......, and the activity of bacteria implicated in the sulfur and nitrogen cycles was analyzed in the biofilms and in the water phase of the bioreactors. Biofilms were a net source of sulfide for the water and gas phases (7.22 ± 5.3 μmol s−1) in the absence of nitrate dosing. Addition of nitrate resulted in a quick...

  12. The production of subjectivities in the Net: Following the trail of a division of applied psychology

    OpenAIRE

    Leal Ferreira, Arthur Arruda; Universidade Federal do Rio de Janeiro; Foureaux, Bruno; Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Torres Brandão, Julia; Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Ruthes Sodré, Karoline; Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Barbosa Verly Miguel, Marcus Vinicius; Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Barbosa Pereira, Natalia; Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil

    2013-01-01

    This paper seeks to bring to the stage the different modes of production of subjectivities engendered by clinical psychological practices and modes of translation and coordination between them. Such research is based on the conceptual Political Epistemology of Stengers and Despret and the Actor-Network Theory of Latour and Law. For these authors, scientific knowledge is produced not as a representation of reality through well-formed sentences, but as modes of articulation between researchers ...

  13. A Global Meta-Analysis on the Impact of Management Practices on Net Global Warming Potential and Greenhouse Gas Intensity from Cropland Soils

    Science.gov (United States)

    Sainju, Upendra M.

    2016-01-01

    Management practices, such as tillage, crop rotation, and N fertilization, may affect net global warming potential (GWP) and greenhouse gas intensity (GHGI), but their global impact on cropland soils under different soil and climatic conditions need further evaluation. Available global data from 57 experiments and 225 treatments were evaluated for individual and combined effects of tillage, cropping systems, and N fertilization rates on GWP and GHGI which accounted for CO2 equivalents from N2O and CH4 emissions with or without equivalents from soil C sequestration rate (ΔSOC), farm operations, and N fertilization. The GWP and GHGI were 66 to 71% lower with no-till than conventional till and 168 to 215% lower with perennial than annual cropping systems, but 41 to 46% greater with crop rotation than monocroppping. With no-till vs. conventional till, GWP and GHGI were 2.6- to 7.4-fold lower when partial than full accounting of all sources and sinks of greenhouse gases (GHGs) were considered. With 100 kg N ha-1, GWP and GHGI were 3.2 to 11.4 times greater with partial than full accounting. Both GWP and GHGI increased curvilinearly with increased N fertilization rate. Net GWP and GHGI were 70 to 87% lower in the improved combined management that included no-till, crop rotation/perennial crop, and reduced N rate than the traditional combined management that included conventional till, monocopping/annual crop, and recommended N rate. An alternative soil respiration method, which replaces ΔSOC by soil respiration and crop residue returned to soil in the previous year, similarly reduced GWP and GHGI by 133 to 158% in the improved vs. the traditional combined management. Changes in GWP and GHGI due to improved vs. traditional management varied with the duration of the experiment and inclusion of soil and climatic factors in multiple linear regressions improved their relationships. Improved management practices reduced GWP and GHGI compared with traditional management

  14. A Global Meta-Analysis on the Impact of Management Practices on Net Global Warming Potential and Greenhouse Gas Intensity from Cropland Soils.

    Science.gov (United States)

    Sainju, Upendra M

    2016-01-01

    Management practices, such as tillage, crop rotation, and N fertilization, may affect net global warming potential (GWP) and greenhouse gas intensity (GHGI), but their global impact on cropland soils under different soil and climatic conditions need further evaluation. Available global data from 57 experiments and 225 treatments were evaluated for individual and combined effects of tillage, cropping systems, and N fertilization rates on GWP and GHGI which accounted for CO2 equivalents from N2O and CH4 emissions with or without equivalents from soil C sequestration rate (ΔSOC), farm operations, and N fertilization. The GWP and GHGI were 66 to 71% lower with no-till than conventional till and 168 to 215% lower with perennial than annual cropping systems, but 41 to 46% greater with crop rotation than monocroppping. With no-till vs. conventional till, GWP and GHGI were 2.6- to 7.4-fold lower when partial than full accounting of all sources and sinks of greenhouse gases (GHGs) were considered. With 100 kg N ha-1, GWP and GHGI were 3.2 to 11.4 times greater with partial than full accounting. Both GWP and GHGI increased curvilinearly with increased N fertilization rate. Net GWP and GHGI were 70 to 87% lower in the improved combined management that included no-till, crop rotation/perennial crop, and reduced N rate than the traditional combined management that included conventional till, monocopping/annual crop, and recommended N rate. An alternative soil respiration method, which replaces ΔSOC by soil respiration and crop residue returned to soil in the previous year, similarly reduced GWP and GHGI by 133 to 158% in the improved vs. the traditional combined management. Changes in GWP and GHGI due to improved vs. traditional management varied with the duration of the experiment and inclusion of soil and climatic factors in multiple linear regressions improved their relationships. Improved management practices reduced GWP and GHGI compared with traditional management

  15. Salinity influences on aboveground and belowground net primary productivity in tidal wetlands

    Science.gov (United States)

    Pierfelice, Kathryn N.; Graeme Lockaby, B.; Krauss, Ken W.; Conner, William H.; Noe, Gregory; Ricker, Matthew C.

    2017-01-01

    Tidal freshwater wetlands are one of the most vulnerable ecosystems to climate change and rising sea levels. However salinification within these systems is poorly understood, therefore, productivity (litterfall, woody biomass, and fine roots) were investigated on three forested tidal wetlands [(1) freshwater, (2) moderately saline, and (3) heavily salt-impacted] and a marsh along the Waccamaw and Turkey Creek in South Carolina. Mean aboveground (litterfall and woody biomass) production on the freshwater, moderately saline, heavily salt-impacted, and marsh, respectively, was 1,061, 492, 79, and 0  g m−2 year−1 versus belowground (fine roots) 860, 490, 620, and 2,128  g m−2 year−1. Litterfall and woody biomass displayed an inverse relationship with salinity. Shifts in productivity across saline sites is of concern because sea level is predicted to continue rising. Results from the research reported in this paper provide baseline data upon which coupled hydrologic/wetland models can be created to quantify future changes in tidal forest functions.

  16. SPECIAL FEATURES OF THE EDUCATIONAL ENVIRONMENT THROUGH THE NET INTERACTION OF EDUCATION AND PRODUCTION

    Directory of Open Access Journals (Sweden)

    Nadezhda V. Silkina

    2015-01-01

    Full Text Available The aim is to explore the features of the educational environment which are observed in educational networking of organization with manufacturing companies.Methods. Theoretical methods: comparison and synthesis of theoretical studies of the Russian and foreign scientists on the concepts of «networking» and «educational environment»; study of regulatory documents of the leaders of the railway industry networking companies with educational organizations; simulation method of educational environment in the networking. Empirical: pedagogical observation, study the experience of networking with other educational institutions and industrial enterprises inRussiaand abroad.Scientific novelty. The authors attempt to fill the gaps in the methodological approach to the study of networking characteristics of the educational environment, emerging as a result of networking and educational organization of production. Definitions of «networking», «educational environment» are proposed, scientific knowledge about networking «educational organization – production» and its impact on the educational environment on the example of railway transport are expanded. The authors propose to consider the concept «networking» as mutually beneficial interaction network association of organizations whose cooperation can meet the challenges of each organization, the subject of networking, in the pursuit of social goals. The «educational environment» is considered by the authors as the area of networking of educational and production systems to facilitate the achievement of the required quality of training by the employer, and includes specially created production – pedagogical conditions. The forms of networking of educational organizations and enterprises are identified by an example of the railway branch.Results. The interpretation of the concepts of «network», «networking», «educational environment» are considered; networking functions (value

  17. Surfactants attenuate gas embolism-induced thrombin production.

    Science.gov (United States)

    Eckmann, David M; Diamond, Scott L

    2004-01-01

    There are no pharmacologic strategies to prevent embolism bubble-induced blood clot formation. The authors conducted experiments to measure thrombin production in sheared whole blood in the presence and absence of bubbles and three surface-active compounds. Blood samples were obtained from six volunteers seven times. The thrombin-specific substrate Boc-VPR-MCA was added to citrated blood diluted with HEPES-buffered saline. Experimental groups were as follows: sparging (air microbubble embolization) with surfactant present; sparging alone; surfactant alone; and neither surfactant nor sparging. The surfactants were Dow Corning Antifoam 1510US, Perftoran, and Pluronic F-127. Blood was sheared by a cone-plate viscometer at 100 and 500 s-1 for 5, 10, and 20 min at 37 degrees C, pipetted into excess stop buffer, and evaluated fluorimetrically. Mean values of fluorescence intensity +/- SDs for each group were compared using ANOVA. Differences were considered significant at P Surfactant addition without sparging did not change thrombin production (P > 0.05). Surfactants attenuated thrombin production in sparged samples 31.8-70.9% (P Surfactants added before sparging attenuate thrombin production. Surfactants may have a clinical application to attenuate gas embolism-induced clotting.

  18. The Economic Impact of Productive Safety Net Program on Poverty: Microeconometrics Analysis, Tigrai National Regional State, Ethiopia

    Directory of Open Access Journals (Sweden)

    Yibrah Hagos Gebresilassie

    2014-08-01

    Full Text Available This paper aims at evaluating the impact of productive safety net program on poverty using primary data from randomly selected 600 households in central zone of Tigrai National Regional State, Ethiopia. Propensity Score Matching and Foster-Greer-Thorbecke were used to evaluate impact of the program and poverty, respectively. The paper revealed that the program has positive and significant effect on consumption, livestock holdings, and productive assets. Moreover, impact of the program on total consumption expenditure per adult equivalent was found to be positive and significant. Using total poverty line, poverty rate was lowest among program participants (30.33% than non-participants (31.1%. Highest poverty rate was found among households headed by women (38.42% while households headed by men (23.1%. The study also revealed that the program has positive and significant effect on poverty reduction and protecting productive assets. Finally, it was recommended that female headed program participants based programs should be provided to help boost their agricultural output and reduce endemic poverty.

  19. Microbial Community Dynamics, Community Respiration, and Net Community Production in Monterey Bay, a Nearshore Upwelling Kelp Forest Environment

    Science.gov (United States)

    Wilson, J.; Litvin, S. Y.; Beman, M.

    2016-02-01

    Upwelling ecosystems, and the extensive kelp forests that can be found in such environments, are extremely productive, supporting extensive food webs and active biogeochemical cycling. However, variation in microbial community dynamics and metabolism—typically a key component of oceanic biogeochemical cycles—are poorly understood within and outside kelp forests. We examined variation in microbial community diversity and composition, planktonic community respiration (CR), net community production (NCP), and gross primary production (GPP) as a function of proximity to kelp (Macrocystis pyrifera) and other variables (i.e. depth, temperature, time, size fractionation) through lab-based and in situ bottle incubations in Monterey Bay, CA. Microbial alpha diversity tended to be higher at shallower depths and inside the kelp forest than outside it, while non-dimensional scaling revealed that variations in beta diversity were driven primarily by date and depth. CR and NCP varied with depth, date, and with proximity to kelp. CR was lower within the kelp forest than outside it, but kelp forest samples exhibited less variation. Inside the kelp forest, a relatively constant rate of CR led to variations in NCP driven by variable GPP, while CR alone appeared to control NCP outside the kelp forest across multiple depths. Taken together, these results speak to the variable nature of the nearshore environment in both space and time, and demonstrate how kelp forests may influence microbial communities and moderate changes in biogeochemical cycling over time.

  20. Estimation and Analysis of Spatiotemporal Dynamics of the Net Primary Productivity Integrating Efficiency Model with Process Model in Karst Area

    Directory of Open Access Journals (Sweden)

    Rui Zhang

    2017-05-01

    Full Text Available Estimates of regional net primary productivity (NPP are useful in modeling regional and global carbon cycles, especially in karst areas. This work developed a new method to study NPP characteristics and changes in Chongqing, a typical karst area. To estimate NPP accurately, the model which integrated an ecosystem process model (CEVSA with a light use efficiency model (GLOPEM called GLOPEM-CEVSA was applied. The fraction of photosynthetically active radiation (fPAR was derived from remote sensing data inversion based on moderate resolution imaging spectroradiometer atmospheric and land products. Validation analyses showed that the PAR and NPP values, which were simulated by the model, matched the observed data well. The values of other relevant NPP models, as well as the MOD17A3 NPP products (NPP MOD17, were compared. In terms of spatial distribution, NPP decreased from northeast to southwest in the Chongqing region. The annual average NPP in the study area was approximately 534 gC/m2a (Std. = 175.53 from 2001 to 2011, with obvious seasonal variation characteristics. The NPP from April to October accounted for 80.1% of the annual NPP, while that from June to August accounted for 43.2%. NPP changed with the fraction of absorbed PAR, and NPP was also significantly correlated to precipitation and temperature at monthly temporal scales, and showed stronger sensitivity to interannual variation in temperature.

  1. Report: EPA Needs to Improve Air Emissions Data for the Oil and Natural Gas Production Sector

    Science.gov (United States)

    Report #13-P-0161, February 20, 2013. High levels of growth in the oil and natural gas (gas) production sector have underscored the need for EPA to gain a better understanding of emissions and potential risks from the production of oil and gas.

  2. Production Optimization for Plan of Gas Field Development Using Marginal Cost Analysis

    Directory of Open Access Journals (Sweden)

    Suprapto Soemardan

    2013-09-01

    Full Text Available Gas production rate is one of the most important variables affecting the feasibility plan of gas field development. It take into account reservoir characteristics, gas reserves, number of wells, production facilities, government take and market conditions. In this research, a mathematical  model of gas production optimization  has been developed using  marginal cost  analysis  in  determining  the  optimum  gas  production  rate  for  economic  profit,  by employing  the  case  study  of Matindok  Field.  The  results  show  that  the  optimum  gas  production  rate  is  mainly  affected  by  gas  price  duration  and time of gas delivery. When the price of gas  increases, the optimum  gas production rate  will increase, and then it  will become closer to the maximum production rate of the reservoir. Increasing the duration time of gas delivery will reduce the optimum gas production rate and increase maximum profit non-linearly.

  3. Life cycle energy and greenhouse gas emissions for an ethanol production process based on blue-green algae.

    Science.gov (United States)

    Luo, Dexin; Hu, Zushou; Choi, Dong Gu; Thomas, Valerie M; Realff, Matthew J; Chance, Ronald R

    2010-11-15

    Ethanol can be produced via an intracellular photosynthetic process in cyanobacteria (blue-green algae), excreted through the cell walls, collected from closed photobioreactors as a dilute ethanol-in-water solution, and purified to fuel grade ethanol. This sequence forms the basis for a biofuel production process that is currently being examined for its commercial potential. In this paper, we calculate the life cycle energy and greenhouse gas emissions for three different system scenarios for this proposed ethanol production process, using process simulations and thermodynamic calculations. The energy required for ethanol separation increases rapidly for low initial concentrations of ethanol, and, unlike other biofuel systems, there is little waste biomass available to provide process heat and electricity to offset those energy requirements. The ethanol purification process is a major consumer of energy and a significant contributor to the carbon footprint. With a lead scenario based on a natural-gas-fueled combined heat and power system to provide process electricity and extra heat and conservative assumptions around the ethanol separation process, the net life cycle energy consumption, excluding photosynthesis, ranges from 0.55 MJ/MJ(EtOH) down to 0.20 MJ/ MJ(EtOH), and the net life cycle greenhouse gas emissions range from 29.8 g CO₂e/MJ(EtOH) down to 12.3 g CO₂e/MJ(EtOH) for initial ethanol concentrations from 0.5 wt % to 5 wt %. In comparison to gasoline, these predicted values represent 67% and 87% reductions in the carbon footprint for this ethanol fuel on a energy equivalent basis. Energy consumption and greenhouse gas emissions can be further reduced via employment of higher efficiency heat exchangers in ethanol purification and/ or with use of solar thermal for some of the process heat.

  4. Evaluation of the gas production economics of the gas hydrate cyclic thermal injection model. [Cyclic thermal injection

    Energy Technology Data Exchange (ETDEWEB)

    Kuuskraa, V.A.; Hammersheimb, E.; Sawyer, W.

    1985-05-01

    The objective of the work performed under this directive is to assess whether gas hydrates could potentially be technically and economically recoverable. The technical potential and economics of recovering gas from a representative hydrate reservoir will be established using the cyclic thermal injection model, HYDMOD, appropriately modified for this effort, integrated with economics model for gas production on the North Slope of Alaska, and in the deep offshore Atlantic. The results from this effort are presented in this document. In Section 1, the engineering cost and financial analysis model used in performing the economic analysis of gas production from hydrates -- the Hydrates Gas Economics Model (HGEM) -- is described. Section 2 contains a users guide for HGEM. In Section 3, a preliminary economic assessment of the gas production economics of the gas hydrate cyclic thermal injection model is presented. Section 4 contains a summary critique of existing hydrate gas recovery models. Finally, Section 5 summarizes the model modification made to HYDMOD, the cyclic thermal injection model for hydrate gas recovery, in order to perform this analysis.

  5. Environmental Life Cycle Analysis of Water and CO2-Based Fracturing Fluids Used in Unconventional Gas Production.

    Science.gov (United States)

    Wilkins, Rodney; Menefee, Anne H; Clarens, Andres F

    2016-12-06

    Many of the environmental impacts associated with hydraulic fracturing of unconventional gas wells are tied to the large volumes of water that such operations require. Efforts to develop nonaqueous alternatives have focused on carbon dioxide as a tunable working fluid even though the full environmental and production impacts of a switch away from water have yet to be quantified. Here we report on a life cycle analysis of using either water or CO 2 for gas production in the Marcellus shale. The results show that CO 2 -based fluids, as currently conceived, could reduce greenhouse gas emissions by 400% (with sequestration credit) and water consumption by 80% when compared to conventional water-based fluids. These benefits are offset by a 44% increase in net energy use when compared to slickwater fracturing as well as logistical barriers resulting from the need to move and store large volumes of CO 2 . Scenario analyses explore the outlook for CO 2 , which under best-case conditions could eventually reduce life cycle energy, water, and greenhouse gas (GHG) burdens associated with fracturing. To achieve these benefits, it will be necessary to reduce CO 2 sourcing and transport burdens and to realize opportunities for improved energy recovery, averted water quality impacts, and carbon storage.

  6. Energy analyses and greenhouse gas emissions assessment for saffron production cycle.

    Science.gov (United States)

    Bakhtiari, Amir Abbas; Hematian, Amir; Sharifi, Azin

    2015-10-01

    Population growth and world climate changes are putting high pressure on agri-food production systems. Exacerbating use of energy sources and expanding the environmental damaging symptoms are the results of these difficult situations. This study was conducted to determine the energy balance for saffron production cycle and investigate the corresponding greenhouse gas (GHG) emissions in Iran. Saffron (Crocus sativus L.) is one of the main spice that historically cultivated in Iran. Data were obtained from 127 randomly selected saffron growers using a face to face questionnaire technique. The results revealed that in 5 years of saffron production cycle, the overall input and output energy use were to be 163,912.09 and 184,868.28 MJ ha(-1), respectively. The highest-level of energy consumption belongs to seeds (23.7 %) followed by chemical fertilizers (23.4 %). Energy use efficiency, specific energy, net energy, and energy productivity of saffron production were 1.1, 13.4 MJ kg(-1), 20,956.2 MJ ha(-1), and 0.1 kg MJ(-1), respectively. The result shows that the cultivation of saffron emits 2325.5 kg CO2 eq. ha(-1) greenhouse gas, in which around 46.5 % belonged to electricity followed by chemical fertilizers. In addition the Cobb-Douglas production function was applied into EViews 7 software to define the functional relationship. The results of econometric model estimation showed that the impact of human labor, electricity, and water for irrigation on stigma, human labor, electricity, and seed on corm and also human labor and farmyard manure (FYM) on flower and leaf yield were found to be statistically significant. Sensitivity analysis results of the energy inputs demonstrated that the marginal physical productivity (MPP) worth of electricity energy was the highest for saffron stigma and corm, although saffron flower and leaf had more sensitivity on chemicals energy inputs. Moreover, MPP values of renewable and indirect energies were higher than non-renewable and

  7. Carbon sequestration in croplands is mainly driven by management leading to increased net primary production - evidence from long-term field experiments in Northern Europe

    Science.gov (United States)

    Kätterer, Thomas; Bolinder, Martin Anders; Börjesson, Gunnar; Kirchmann, Holger; Poeplau, Christopher

    2014-05-01

    Sustainable intensification of agriculture in regions with high production potential is a prerequisite for providing services for an increasing human population, not only food, animal feed, fiber and biofuel but also to promote biodiversity and the beauty of landscapes. We investigated the effect of different management practices on soil fertility and carbon sequestration in long-term experiments, mainly from Northern Europe. In addition, a meta-analysis on the effect of catch crops was conducted. Improved management of croplands was found to be a win-win strategy resulting in both increased soil fertility and carbon sequestration. We quantified the effect of different management practices such as N fertilization, organic amendments, catch crops and ley-arable rotations versus continuous annual cropping systems on soil carbon stocks. Increasing net primary productivity (NPP) was found to be the main driver for higher soil carbon storage. Mineral N fertilization increased soil carbon stocks by 1-2 kg C ha-1 for each kg of N applied to cropland. Ley-arable rotations, being a combination of annual and perennial crops, are expected to have C stocks intermediate between those of continuous grass- and croplands. A summary of data from 15 long-term sites showed that on average 0.5 Mg ha-1 yr-1 (range 0.3 to 1.1; median 0.4 Mg ha-1 yr-1) more carbon was retained in soils in ley-arable compared to exclusively annual systems, depending on species composition, management, soil depth and the duration of the studies. The annual C accumulation rate for catch crops determined in the meta-analysis was well within that range (0.32±0.08 Mg C ha-1 yr-1). Retention factors calculated for straw, manure, sawdust, peat, sewage sludge and composted household waste varied widely in a decadal time scale. Retention of root and rhizodeposit carbon was higher than for above-ground crop residues. We conclude that NPP is the major driver for C sequestration and emphasize that increased soil

  8. Review of Well Operator Files for Hydraulically Fractured Oil and Gas Production Wells: Hydraulic Fracturing Operations

    Science.gov (United States)

    EPA conducted a survey of oil and gas production wells hydraulically fractured by nine oil and gas service companies in the United States during 2009 and 2010. This is the second well file review report.

  9. Reservoir controls on the occurrence and production of gas hydrates in nature

    Science.gov (United States)

    Collett, Timothy Scott

    2014-01-01

    Gas hydrates in both arctic permafrost regions and deep marine settings can occur at high concentrations in sand-dominated reservoirs, which have been the focus of gas hydrate exploration and production studies in

  10. Gas sector expansion: production monopoly versus free prices; Expansao do setor de gas: monopolio na producao versus precos livres

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Maria Paula de Souza [Agencia de Servicos Publicos de Energia do Estado do Espirito Santo (ASPE), Vitoria, ES (Brazil)

    2006-07-01

    This paper describes the necessary conditions to develop Brazil's natural gas sector with production, reserves, main uses, sources, inputs, main players, laws, regulatory aspects, prices, supply, demand, market, monopoly and free competition. (author)

  11. Control of Greenhouse Gas Emissions by Optimal DER Technology Investment and Energy Management in Zero-Net-Energy Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, Michael; Siddiqui, Afzal; Marnay, Chris; Aki, Hirohisa; Lai, Judy

    2009-08-10

    The U.S. Department of Energy has launched the commercial building initiative (CBI) in pursuit of its research goal of achieving zero-net-energy commercial buildings (ZNEB), i.e. ones that produce as much energy as they use. Its objective is to make these buildings marketable by 2025 such that they minimize their energy use through cutting-edge, energy-efficiency technologies and meet their remaining energy needs through on-site renewable energy generation. This paper examines how such buildings may be implemented within the context of a cost- or CO2-minimizing microgrid that is able to adopt and operate various technologies: photovoltaic modules (PV) and other on-site generation, heat exchangers, solar thermal collectors, absorption chillers, and passive/demand-response technologies. A mixed-integer linear program (MILP) that has a multi-criteria objective function is used. The objective is minimization of a weighted average of the building's annual energy costs and CO2 emissions. The MILP's constraints ensure energy balance and capacity limits. In addition, constraining the building's energy consumed to equal its energy exports enables us to explore how energy sales and demand-response measures may enable compliance with the ZNEB objective. Using a commercial test site in northernCalifornia with existing tariff rates and technology data, we find that a ZNEB requires ample PV capacity installed to ensure electricity sales during the day. This is complemented by investment in energy-efficient combined heat and power (CHP) equipment, while occasional demand response shaves energy consumption. A large amount of storage is also adopted, which may be impractical. Nevertheless, it shows the nature of the solutions and costs necessary to achieve a ZNEB. Additionally, the ZNEB approach does not necessary lead to zero-carbon (ZC) buildings as is frequently argued. We also show a multi-objective frontier for the CA example, whichallows us to estimate the

  12. GRANULATION AND BRIQUETTING OF SOLID PRODUCTS FROM FLUE GAS DESULFURIZATION

    Directory of Open Access Journals (Sweden)

    Jan J. Hycnar

    2015-11-01

    Full Text Available Most flue gas desulfurization products can be characterized by significant solubility in water and dusting in dry state. These characteristics can cause a considerable pollution of air, water, and soil. Among many approaches to utilization of this waste, the process of agglomeration using granulation or briquetting has proved very effective. Using desulfurization products a new material of aggregate characteristics has been acquired, and this material is resistant to water and wind erosion as well as to the conditions of transportation and storage. The paper presents the results of industrial trials granulation and briquetting of calcium desulphurization products. The granulation of a mixture of phosphogypsum used with fly ash (in the share 1:5. The resulting granules characterized by a compressive strength of 41.6 MPa, the damping resistance of 70% and 14.2% abrasion. The granulate was used for the production of cement mix. The produced concrete mortar have a longer setting and hardening time, as compared to the traditional ash and gypsum mortar, and have a higher or comparable flexural and compressive strength during hardening. Briquetting trials made of a product called synthetic gypsum or rea-gypsum both in pure form and with the addition of 5% and 10% of the limestone dust. Briquettes have a high initial strength and resistance to abrasion. The values ​​of these parameters increased after 72 hours of seasoning. It was found that higher hardiness of briquettes with rea-gypsum was obtained with the impact of atmospheric conditions and higher resistance to elution of water-soluble components in comparison to ash briquettes.

  13. Developments in greenhouse gas emissions and net energy use in Danish agriculture - How to achieve substantial CO2 reduction?

    DEFF Research Database (Denmark)

    Dalgaard, Tommy; Olesen, Jørgen E; Petersen, Søren O

    2011-01-01

    emissions in the form of methane, nitrous oxide and carbon dioxide (including carbon sources and sinks, and the impact of energy consumption/bioenergy production) from Danish agriculture in the years 1990–2010. An analysis of possible measures to reduce the GHG emissions indicated that a 50–70% reduction...

  14. Analysis of Specific Features of the Ukrainian Market of Natural Gas Production and Consumption

    OpenAIRE

    Lelyuk Oleksiy V.

    2013-01-01

    The article provides results of the study of specific features of the Ukrainian market of natural gas production and consumption. It analyses dynamics of the specific weight of Ukraine in general volumes of natural gas consumption in the world, dynamics of natural gas consumption in Ukraine during 1990 – 2012 and dependence of natural gas consumption on GDP volumes by the purchasing power parity. It studies the structure of natural gas consumption by regions in 2012 and sectors of economy, re...

  15. Topographical effects of climate dataset and their impacts on the estimation of regional net primary productivity

    Science.gov (United States)

    Sun, L. Qing; Feng, Feng X.

    2014-11-01

    In this study, we first built and compared two different climate datasets for Wuling mountainous area in 2010, one of which considered topographical effects during the ANUSPLIN interpolation was referred as terrain-based climate dataset, while the other one did not was called ordinary climate dataset. Then, we quantified the topographical effects of climatic inputs on NPP estimation by inputting two different climate datasets to the same ecosystem model, the Boreal Ecosystem Productivity Simulator (BEPS), to evaluate the importance of considering relief when estimating NPP. Finally, we found the primary contributing variables to the topographical effects through a series of experiments given an overall accuracy of the model output for NPP. The results showed that: (1) The terrain-based climate dataset presented more reliable topographic information and had closer agreements with the station dataset than the ordinary climate dataset at successive time series of 365 days in terms of the daily mean values. (2) On average, ordinary climate dataset underestimated NPP by 12.5% compared with terrain-based climate dataset over the whole study area. (3) The primary climate variables contributing to the topographical effects of climatic inputs for Wuling mountainous area were temperatures, which suggest that it is necessary to correct temperature differences for estimating NPP accurately in such a complex terrain.

  16. Iron fertilization enhanced net community production but not downward particle flux during the Southern Ocean iron fertilization experiment LOHAFEX

    Science.gov (United States)

    Martin, Patrick; van der Loeff, Michiel Rutgers; Cassar, Nicolas; Vandromme, Pieter; d'Ovidio, Francesco; Stemmann, Lars; Rengarajan, R.; Soares, Melena; González, Humberto E.; Ebersbach, Friederike; Lampitt, Richard S.; Sanders, Richard; Barnett, Bruce A.; Smetacek, Victor; Naqvi, S. Wajih A.

    2013-09-01

    closed eddy core in the Subantarctic Atlantic Ocean was fertilized twice with two tons of iron (as FeSO4), and the 300 km2 fertilized patch was studied for 39 days to test whether fertilization enhances downward particle flux into the deep ocean. Chlorophyll a and primary productivity doubled after fertilization, and photosynthetic quantum yield (FV/FM) increased from 0.33 to ≥0.40. Silicic acid (artificially fertilized bloom with very low diatom biomass. Net community production (NCP) inside the patch, estimated from O2:Ar ratios, averaged 21 mmol POC m-2 d-1, probably ±20%. 234Th profiles implied constant export of 6.3 mmol POC m-2 d-1 in the patch, similar to unfertilized waters. The difference between NCP and 234Th-derived export partly accumulated in the mixed layer and was partly remineralized between the mixed layer and 100 m. Neutrally buoyant sediment traps at 200 and 450 m inside and outside the patch caught mostly fertilization. Our data thus indicate intense flux attenuation between 100 and 200 m, and probably between the mixed layer and 100 m. We attribute the lack of fertilization-induced export to silicon limitation of diatoms and reprocessing of sinking particles by detritus feeders. Our data are consistent with the view that nitrate-rich but silicate-deficient waters are not poised for enhanced particle export upon iron addition.

  17. Determination of Nutrient Contents and Gas Production Values of Some Legume Forages Grown in the Harran Plain Saline Soils

    Directory of Open Access Journals (Sweden)

    M. Boga

    2014-06-01

    Full Text Available The aim of this study was to determine the nutritive value of some legume species in salt-affected soils of South-East Anatolian region using chemical composition and in vitro gas production kinetics. In this study, Lotus corniculatus, Trifolium alexandrinum, Medicago sativa were sown and tested in four different locations. A 3 by 4 factorial design with 3 legume species and 4 salt levels (non salty electrical conductivity (ECECECEC was used in the study. Results indicated that salinity and plants had no significant effect on ash and ether extract. Dry matter (DM, acid detergent fiber, digestible dry matter, dry matter intake (DMI were affected by plant, salinity and plant×salinity interaction. On the other hand neutral detergent fiber, relative feed value (RFV, and DMI were affected by salinity and plant×salinity interaction. Mineral contents were affected by plant species, salinity and salinity×plants interactions. In vitro gas production, their kinetics and estimated parameters such as were not affected by salinity whereas the gas production up to 48 h, organic matter digestibility, metabolizable energy (ME, and net energy lactation (NEL were affected by plant and plant×salt interaction. Generally RFVs of all species ranged from 120 to 210 and were quite satisfactory in salty conditions. Current results show that the feed value of Medicago sativa is higher compared to Lotus corniculatus and Trifolium alexandrinum.

  18. Changes of net primary productivity in China during recent 11 years detected using an ecological model driven by MODIS data

    Science.gov (United States)

    Liu, Yibo; Ju, Weimin; He, Honglin; Wang, Shaoqiang; Sun, Rui; Zhang, Yuandong

    2013-03-01

    Net primary productivity (NPP) is an important component of the terrestrial carbon cycle. Accurately mapping the spatial-temporal variations of NPP in China is crucial for global carbon cycling study. In this study the process-based Boreal Ecosystem Productivity Simulator (BEPS) was employed to study the changes of NPP in China's ecosystems for the period from 2000 to 2010. The BEPS model was first validated using gross primary productivity (GPP) measured at typical flux sites and forest NPP measured at different regions. Then it was driven with leaf area index (LAI) inversed from the Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance and land cover products and meteorological data interpolated from observations at 753 national basic meteorological stations to simulate NPP at daily time steps and a spatial resolution of 500 m from January 1, 2000 to December 31, 2010. Validations show that BEPS is able to capture the seasonal variations of tower-based GPP and the spatial variability of forest NPP in different regions of China. Estimated national total of annual NPP varied from 2.63 to 2.84Pg C·yr-1, averaging 2.74 Pg C·yr-1 during the study period. Simulated terrestrial NPP shows spatial patterns decreasing from the east to the west and from the south to the north, in association with land cover types and climate. South-west China makes the largest contribution to the national total of NPP while NPP in the North-west account for only 3.97% of the national total. During the recent 11 years, the temporal changes of NPP were heterogamous. NPP increased in 63.8% of China's landmass, mainly in areas north of the Yangtze River and decreased in most areas of southern China, owing to the low temperature freezing in early 2008 and the severe drought in late 2009.

  19. Greenhouse gas production in wastewater treatment: process selection is the major factor.

    Science.gov (United States)

    Keller, J; Hartley, K

    2003-01-01

    Many practical design and operating decisions on wastewater treatment plants can have significant impacts on the overall environmental performance, in particular the greenhouse gas (GHG) emissions. The main factor in this regard is the use of aerobic or anaerobic treatment technology. This paper compares the GHG production of a number of case studies with aerobic or anaerobic main and sludge treatment of domestic wastewater and also looks at the energy balances and economics. This comparison demonstrates that major advantages can be gained by using primarily anaerobic processes as it is possible to largely eliminate any net energy input to the process, and therefore the production of GHG from fossil fuels. This is achieved by converting the energy of the incoming wastewater pollutants to methane which is then used to generate electricity. This is sufficient to power the aerobic processes as well as the mixing etc. of the anaerobic stages. In terms of GHG production, the total output (in CO2 equivalents) can be reduced from 2.4 kg CO2/kg COD(removed) for fully aerobic treatment to 1.0 kg CO2/kg COD(removed) for primarily anaerobic processes. All of the CO2 produced in the anaerobic processes comes from the wastewater pollutants and is therefore greenhouse gas neutral, whereas up to 1.4 kg CO2/kg COD(removed) originates from power generation for the fully aerobic process. This means that considerably more CO2 is produced in power generation than in the actual treatment process, and all of this is typically from fossil fuels, whereas the energy from the wastewater pollutants comes primarily from renewable energy sources, namely agricultural products. Even a change from anaerobic to aerobic sludge treatment processes (for the same aerobic main process) has a massive impact on the CO2 production from fossil fuels. An additional 0.8 kg CO2/kg COD(removed) is produced by changing to aerobic sludge digestion, which equates for a typical 100,000 EP plant to an additional

  20. Natural Gas and Cellulosic Biomass: A Clean Fuel Combination? Determining the Natural Gas Blending Wall in Biofuel Production.

    Science.gov (United States)

    M Wright, Mark; Seifkar, Navid; Green, William H; Román-Leshkov, Yuriy

    2015-07-07

    Natural gas has the potential to increase the biofuel production output by combining gas- and biomass-to-liquids (GBTL) processes followed by naphtha and diesel fuel synthesis via Fischer-Tropsch (FT). This study reflects on the use of commercial-ready configurations of GBTL technologies and the environmental impact of enhancing biofuels with natural gas. The autothermal and steam-methane reforming processes for natural gas conversion and the gasification of biomass for FT fuel synthesis are modeled to estimate system well-to-wheel emissions and compare them to limits established by U.S. renewable fuel mandates. We show that natural gas can enhance FT biofuel production by reducing the need for water-gas shift (WGS) of biomass-derived syngas to achieve appropriate H2/CO ratios. Specifically, fuel yields are increased from less than 60 gallons per ton to over 100 gallons per ton with increasing natural gas input. However, GBTL facilities would need to limit natural gas use to less than 19.1% on a LHV energy basis (7.83 wt %) to avoid exceeding the emissions limits established by the Renewable Fuels Standard (RFS2) for clean, advanced biofuels. This effectively constitutes a blending limit that constrains the use of natural gas for enhancing the biomass-to-liquids (BTL) process.

  1. Climatic variability, hydrologic anomaly, and methane emission can turn productive freshwater marshes into net carbon sources.

    Science.gov (United States)

    Chu, Housen; Gottgens, Johan F; Chen, Jiquan; Sun, Ge; Desai, Ankur R; Ouyang, Zutao; Shao, Changliang; Czajkowski, Kevin

    2015-03-01

    Freshwater marshes are well-known for their ecological functions in carbon sequestration, but complete carbon budgets that include both methane (CH4 ) and lateral carbon fluxes for these ecosystems are rarely available. To the best of our knowledge, this is the first full carbon balance for a freshwater marsh where vertical gaseous [carbon dioxide (CO2 ) and CH4 ] and lateral hydrologic fluxes (dissolved and particulate organic carbon) have been simultaneously measured for multiple years (2011-2013). Carbon accumulation in the sediments suggested that the marsh was a long-term carbon sink and accumulated ~96.9 ± 10.3 (±95% CI) g C m(-2)  yr(-1) during the last ~50 years. However, abnormal climate conditions in the last 3 years turned the marsh to a source of carbon (42.7 ± 23.4 g C m(-2)  yr(-1) ). Gross ecosystem production and ecosystem respiration were the two largest fluxes in the annual carbon budget. Yet, these two fluxes compensated each other to a large extent and led to the marsh being a CO2 sink in 2011 (-78.8 ± 33.6 g C m(-2)  yr(-1) ), near CO2 -neutral in 2012 (29.7 ± 37.2 g C m(-2)  yr(-1) ), and a CO2 source in 2013 (92.9 ± 28.0 g C m(-2)  yr(-1) ). The CH4 emission was consistently high with a three-year average of 50.8 ± 1.0 g C m(-2)  yr(-1) . Considerable hydrologic carbon flowed laterally both into and out of the marsh (108.3 ± 5.4 and 86.2 ± 10.5 g C m(-2)  yr(-1) , respectively). In total, hydrologic carbon fluxes contributed ~23 ± 13 g C m(-2)  yr(-1) to the three-year carbon budget. Our findings highlight the importance of lateral hydrologic inflows/outflows in wetland carbon budgets, especially in those characterized by a flow-through hydrologic regime. In addition, different carbon fluxes responded unequally to climate variability/anomalies and, thus, the total carbon budgets may vary drastically among years. © 2014 John Wiley & Sons Ltd.

  2. Ruminal Methane Production on Simple Phenolic Acids Addition in in Vitro Gas Production Method

    Directory of Open Access Journals (Sweden)

    A. Jayanegara

    2009-04-01

    Full Text Available Methane production from ruminants contributes to total global methane production, which is an important contributor to global warming. In this experiment, six sources of simple phenolic acids (benzoic, cinnamic, phenylacetic, caffeic, p-coumaric and ferulic acids at two different levels (2 and 5 mM added to hay diet were evaluated for their potential to reduce enteric methane production using in vitro Hohenheim gas production method. The measured variables were gas production, methane, organic matter digestibility (OMD, and short chain fatty acids (SCFA. The results showed that addition of cinnamic, caffeic, p-coumaric and ferulic acids at 5 mM significantly (P p-coumaric > ferulic > cinnamic. The addition of simple phenols did not significantly decrease OMD. Addition of simple phenols tends to decrease total SCFA production. It was concluded that methane decrease by addition of phenolic acids was relatively small, and the effect of phenolic acids on methane decrease depended on the source and concentration applied.

  3. Net Locality

    DEFF Research Database (Denmark)

    de Souza e Silva, Adriana Araujo; Gordon, Eric

    Provides an introduction to the new theory of Net Locality and the profound effect on individuals and societies when everything is located or locatable. Describes net locality as an emerging form of location awareness central to all aspects of digital media, from mobile phones, to Google Maps...... of emerging technologies, from GeoCities to GPS, Wi-Fi, Wiki Me, and Google Android....

  4. Net Neutrality

    DEFF Research Database (Denmark)

    Savin, Andrej

    2017-01-01

    Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else.......Repealing “net neutrality” in the US will have no bearing on Internet freedom or security there or anywhere else....

  5. Modeling, Analysis and Simulation of Simple One Machine-Two Product System Using Petri Nets = Basit Bir Makine-İki Ürün Sisteminin Petri Ağları Kullanılarak Modellenmesi, Analizi ve Simulasyonu

    Directory of Open Access Journals (Sweden)

    Özgür ARMANERİ

    2006-01-01

    Full Text Available As in many engineering fields, the design of manufacturing systems can be carried out using models. Petri nets have been used extensively to model and analyze manufacturing systems. Petri Nets, as graphical and mathematical tools, provide a uniform environment for modeling, format analysis and design of discrete event systems. The modeling, simulation and analysis of simple one machine-two product systems using Petri nets will be presented in this paper. Behavioral and structural properties of the Petri net model will be considered in details. Then, the Petri net model of one machine-two product system will be simulated using a simulation program.

  6. 76 FR 67201 - Information Collection Activities: Oil and Gas Production Safety Systems; Submitted for Office of...

    Science.gov (United States)

    2011-10-31

    ... Production Safety Systems; Submitted for Office of Management and Budget (OMB) Review; Comment Request ACTION... the paperwork requirements in the regulations under Subpart H, ``Oil and Gas Production Safety Systems... H, Oil and Gas Production Safety Systems. Abstract: The Outer Continental Shelf (OCS) Lands Act, as...

  7. Multi-Agents in the North Sea – The Case of Oil and Gas Production

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Lindegaard; Demazeau, Yves; Jørgensen, Bo Nørregaard

    2011-01-01

    Developing control systems for offshore oil and gas production is a challenging task, due to the complex inherent issues of the domain, i.e. changing properties of the oil and gas reservoirs, and variations in production configuration, due to new wells and production technologies. In this paper, we...

  8. Greenhouse gas impacts of natural gas: Influence of deployment choice, methane leak rate, and methane GWP

    Science.gov (United States)

    Cohan, D. S.

    2015-12-01

    Growing supplies of natural gas have heightened interest in the net impacts of natural gas on climate. Although its production and consumption result in greenhouse gas emissions, natural gas most often substitutes for other fossil fuels whose emission rates may be higher. Because natural gas can be used throughout the sectors of the energy economy, its net impacts on greenhouse gas emissions will depend not only on the leak rates of production and distribution, but also on the use for which natural gas is substituted. Here, we present our estimates of the net greenhouse gas emissions impacts of substituting natural gas for other fossil fuels for five purposes: light-duty vehicles, transit buses, residential heating, electricity generation, and export for electricity generation overseas. Emissions are evaluated on a fuel cycle basis, from production and transport of each fuel through end use combustion, based on recent conditions in the United States. We show that displacement of existing coal-fired electricity and heating oil furnaces yield the largest reductions in emissions. The impact of compressed natural gas replacing petroleum-based vehicles is highly uncertain, with the sign of impact depending on multiple assumptions. Export of liquefied natural gas for electricity yields a moderate amount of emissions reductions. We further show how uncertainties in upstream emission rates for natural gas and in the global warming potential of methane influence the net greenhouse gas impacts. Our presentation will make the case that how natural gas is deployed is crucial to determining how it will impact climate.

  9. The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones

    Directory of Open Access Journals (Sweden)

    N. Cassar

    2011-02-01

    Full Text Available The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ and the northern reaches of the Polar Frontal Zone (PFZ, we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense study, which occurred in January–February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m−2 d−1. NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m, dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. The strong correlation between NCP and dissolved Fe may be difficult to interpret because of the correlation of dissolved Fe to MLD and because the concentration of iron may not be a good indicator of its availability. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer.

  10. Switching from monoculture to polyculture farming benefits birds in oil palm production landscapes: Evidence from mist netting data.

    Science.gov (United States)

    Yahya, Muhammad S; Syafiq, Muhamad; Ashton-Butt, Adham; Ghazali, Amal; Asmah, Siti; Azhar, Badrul

    2017-08-01

    Monoculture farming is pervasive in industrial oil palm agriculture, including those RSPO plantations certified as sustainably managed. This farming practice does not promote the maintenance of farmland biodiversity. However, little scientific attention has been given to polyculture farming in oil palm production landscapes. Polyculture farming is likely to increase the floristic diversity and stand structural complexity that underpins biodiversity. Mist nets were used to sample birds at 120 smallholdings in Peninsular Malaysia. At each site, 12 vegetation structure characteristics were measured. We compared bird species richness, abundance, and composition between monoculture and polyculture smallholdings and used predictive models to examine the effects of habitat quality on avian biodiversity. Bird species richness was significantly greater in polyculture than that of monoculture smallholdings. The number of fallen and standing, dead oil palms were also important positive predictors of species richness. Bird abundance was also strongly increased by standing and dead oil palms and decreased with oil palm stand height. Our results indicate that polyculture farming can improve bird species richness in oil palm production landscapes. In addition, key habitat variables that are closely associated with farming practices, such as the removal of dead trees, should and can be managed by oil palm growers in order to promote biodiversity. To increase the sustainability of oil palm agriculture, it is imperative that stakeholders modify the way oil palms are currently planted and managed. Our findings can guide policy makers and certification bodies to promote oil palm production landscapes that will function more sustainably and increase existing biodiversity of oil palm landscapes.

  11. Variation and Trends of Landscape Dynamics, Land Surface Phenology and Net Primary Production of the Appalachian Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yeqiao; Zhao, Jianjun; Zhou, Yuyu; Zhang, Hongyan

    2012-12-15

    The gradients of the Appalachian Mountains in elevations and latitudes provide a unique regional perspective of landscape variations in the eastern United States and a section of the southeastern Canada. This study reveals patterns and trends of landscape dynamics, land surface phenology and ecosystem production along the Appalachian Mountains using time series data from Global Inventory Modeling and Mapping Studies (GIMMS) and AVHRR Global Production Efficiency Model (GloPEM) datasets. We analyzed the spatial and temporal patterns of Normalized Difference Vegetation Index (NDVI), length of growing season (LOS) and net primary production (NPP) of selected ecoregions along the Appalachian Mountains regions. We compared the results out of the Appalachian Mountains regions in different spatial contexts including the North America and the Appalachian Trail corridor area. To reveal latitudinal variations we analyzed data and compared the results between 30°N-40°N and 40°N-50°N latitudes. The result revealed significant decreases in annual peak NDVI in the Appalachian Mountains regions. The trend for the Appalachian Mountains regions was -0.0018 (R2=0.55, P<0.0001) NDVI unit decrease per year during 25 years between 1982 and 2006. The LOS had prolonged 0.3 day yr-1 during 25 years over the Appalachian Mountains regions. The NPP increased by 2.68 gC m-2yr-2 in Appalachian Mountains regions from 1981 to 2000. The comparison with the North America reveals the effects of topography and ecosystem compositions of the Appalachian Mountains. The comparison with the Appalachian Trail corridor area provides a regional mega-transect view of the measured variables.

  12. Effects of tillage practices and straw returning methods on greenhouse gas emissions and net ecosystem economic budget in rice-wheat cropping systems in central China

    Science.gov (United States)

    Zhang, Z. S.; Guo, L. J.; Liu, T. Q.; Li, C. F.; Cao, C. G.

    2015-12-01

    Significant efforts have been devoted to assess the effects of conservation tillage (no-tillage [NT] and straw returning) on greenhouse gas (GHG) emissions, global warming potential (GWP), greenhouse gas intensity (GHGI), and net economic budget in crop growing seasons. However, only a few studies have evaluated the effects conservation tillage on the net ecosystem economic budget (NEEB) in a rice-wheat cropping system. Therefore, a split-plot field experiment was performed to comprehensively evaluate the effects of tillage practices (i.e., conventional intensive tillage [CT] and NT) and straw returning methods (i.e., straw returning or removal of preceding crop) on the soil total organic carbon (TOC), GHG emissions, GWP, GHGI, and NEEB of sandy loam soil in a rice-wheat cropping system in central China. Conservation tillage did not affect rice and wheat grain yields. Compared with CT and straw removal, NT and straw returning significantly increased the TOC of 0-5 cm soil layer by 2.9% and 7.8%, respectively. However, the TOC of 0-20 cm soil layer was not affected by tillage practices and straw returning methods. NT did not also affect the N2O emissions during the rice and wheat seasons; NT significantly decreased the annual CH4 emissions by 7.5% and the annual GWP by 7.8% compared with CT. Consequently, GHGI under NT was reduced by 8.1%. Similar to NT, straw returning did not affect N2O emissions during the rice and wheat seasons. Compared with straw removal, straw returning significantly increased annual CH4 emissions by 35.0%, annual GWP by 32.0%, and annual GHGI by 31.1%. Straw returning did not also affect NEEB; by contrast, NT significantly increased NEEB by 15.6%. NT without straw returning resulted in the lowest GWP, the lowest GHGI, and the highest NEEB among all treatments. This finding suggested that NT without straw returning may be applied as a sustainable technology to increase economic and environmental benefits. Nevertheless, environmentally straw

  13. Net global warming potential and greenhouse gas intensity in a double-cropping cereal rotation as affected by nitrogen and straw management

    Science.gov (United States)

    Huang, T.; Gao, B.; Christie, P.; Ju, X.

    2013-12-01

    The effects of nitrogen and straw management on global warming potential (GWP) and greenhouse gas intensity (GHGI) in a winter wheat-summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq) from greenhouse gas emissions, agricultural inputs and management practices, as well as changes in soil organic carbon (SOC), based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero N (control), optimum and conventional N) and straw removal (i.e. N0, Nopt and Ncon) or return (i.e. SN0, SNopt and SNcon). Optimum N management (Nopt, SNopt) saved roughly half of the fertilizer N compared to conventional agricultural practice (Ncon, SNcon), with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha-1 in Ncon and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of Nopt and SNopt. Straw return increased annual mean N2O emissions by 27.9%. Annual SOC sequestration was 0.40-1.44 Mg C ha-1 yr-1 in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51%, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat-summer maize double-cropping system.

  14. Net global warming potential and greenhouse gas intensity in a double cropping cereal rotation as affected by nitrogen and straw management

    Science.gov (United States)

    Huang, T.; Gao, B.; Christie, P.; Ju, X.

    2013-08-01

    The effects of nitrogen and straw management on global warming potential (GWP) and greenhouse gas intensity (GHGI) in a winter wheat-summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq) from greenhouse gas emissions, agricultural inputs and management practices, and changes in soil organic carbon (SOC), based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero-N control, optimum and conventional N) and straw removal (i.e. N0, Nopt and Ncon) or return (i.e. N0, Nopt and SNcon). Optimum N management (Nopt, SNopt) saved roughly half of the fertilizer N compared to conventional agricultural practice (Ncon, SNcon) with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha-1 in Ncon and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of Nopt and SNopt. Straw return increased annual mean N2O emissions by 27.9%. Annual SOC sequestration was 0.40-1.44 Mg C ha-1 yr-1 in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51%, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat-summer maize double-cropping system.

  15. Assessing the greenhouse gas emissions of Brazilian soybean biodiesel production.

    Science.gov (United States)

    Cerri, Carlos Eduardo Pellegrino; You, Xin; Cherubin, Maurício Roberto; Moreira, Cindy Silva; Raucci, Guilherme Silva; Castigioni, Bruno de Almeida; Alves, Priscila Aparecida; Cerri, Domingos Guilherme Pellegrino; Mello, Francisco Fujita de Castro; Cerri, Carlos Clemente

    2017-01-01

    Soybean biodiesel (B100) has been playing an important role in Brazilian energy matrix towards the national bio-based economy. Greenhouse gas (GHG) emissions is the most widely used indicator for assessing the environmental sustainability of biodiesels and received particular attention among decision makers in business and politics, as well as consumers. Former studies have been mainly focused on the GHG emissions from the soybean cultivation, excluding other stages of the biodiesel production. Here, we present a holistic view of the total GHG emissions in four life cycle stages for soybean biodiesel. The aim of this study was to assess the GHG emissions of Brazilian soybean biodiesel production system with an integrated life cycle approach of four stages: agriculture, extraction, production and distribution. Allocation of mass and energy was applied and special attention was paid to the integrated and non-integrated industrial production chain. The results indicated that the largest source of GHG emissions, among four life cycle stages, is the agricultural stage (42-51%) for B100 produced in integrated systems and the production stage (46-52%) for B100 produced in non-integrated systems. Integration of industrial units resulted in significant reduction in life cycle GHG emissions. Without the consideration of LUC and assuming biogenic CO2 emissions is carbon neutral in our study, the calculated life cycle GHG emissions for domestic soybean biodiesel varied from 23.1 to 25.8 gCO2eq. MJ-1 B100 and those for soybean biodiesel exported to EU ranged from 26.5 to 29.2 gCO2eq. MJ-1 B100, which represent reductions by 65% up to 72% (depending on the delivery route) of GHG emissions compared with the EU benchmark for diesel fuel. Our findings from a life cycle perspective contributed to identify the major GHG sources in Brazilian soybean biodiesel production system and they can be used to guide mitigation priority for policy and decision-making. Projected scenarios in this

  16. Assessing the greenhouse gas emissions of Brazilian soybean biodiesel production.

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Pellegrino Cerri

    Full Text Available Soybean biodiesel (B100 has been playing an important role in Brazilian energy matrix towards the national bio-based economy. Greenhouse gas (GHG emissions is the most widely used indicator for assessing the environmental sustainability of biodiesels and received particular attention among decision makers in business and politics, as well as consumers. Former studies have been mainly focused on the GHG emissions from the soybean cultivation, excluding other stages of the biodiesel production. Here, we present a holistic view of the total GHG emissions in four life cycle stages for soybean biodiesel. The aim of this study was to assess the GHG emissions of Brazilian soybean biodiesel production system with an integrated life cycle approach of four stages: agriculture, extraction, production and distribution. Allocation of mass and energy was applied and special attention was paid to the integrated and non-integrated industrial production chain. The results indicated that the largest source of GHG emissions, among four life cycle stages, is the agricultural stage (42-51% for B100 produced in integrated systems and the production stage (46-52% for B100 produced in non-integrated systems. Integration of industrial units resulted in significant reduction in life cycle GHG emissions. Without the consideration of LUC and assuming biogenic CO2 emissions is carbon neutral in our study, the calculated life cycle GHG emissions for domestic soybean biodiesel varied from 23.1 to 25.8 gCO2eq. MJ-1 B100 and those for soybean biodiesel exported to EU ranged from 26.5 to 29.2 gCO2eq. MJ-1 B100, which represent reductions by 65% up to 72% (depending on the delivery route of GHG emissions compared with the EU benchmark for diesel fuel. Our findings from a life cycle perspective contributed to identify the major GHG sources in Brazilian soybean biodiesel production system and they can be used to guide mitigation priority for policy and decision-making. Projected

  17. Estimating Damage Cost of Net Primary Production due to Climate Change and Ozone(O3) Effect

    Science.gov (United States)

    Park, J. H.; Lee, D. K.; Park, C.; Sung, S.; Kim, H. G.; Mo, Y.; Kim, S.; Kil, S.

    2016-12-01

    productivity, net primary productivity (NPP), in Korea is about 622 gC/m2/yr in the results. And the result shows that NPP decreases about 2.3% by O3 negative effect. The NPP in the future also decreases about 1-2% and the negative effect of O3 is similar. Finally, damage cost by O3 in the future is bigger than damage by climate change.

  18. Modeling the Relative GHG Emissions of Conventional and Shale Gas Production

    Science.gov (United States)

    2011-01-01

    Recent reports show growing reserves of unconventional gas are available and that there is an appetite from policy makers, industry, and others to better understand the GHG impact of exploiting reserves such as shale gas. There is little publicly available data comparing unconventional and conventional gas production. Existing studies rely on national inventories, but it is not generally possible to separate emissions from unconventional and conventional sources within these totals. Even if unconventional and conventional sites had been listed separately, it would not be possible to eliminate site-specific factors to compare gas production methods on an equal footing. To address this difficulty, the emissions of gas production have instead been modeled. In this way, parameters common to both methods of production can be held constant, while allowing those parameters which differentiate unconventional gas and conventional gas production to vary. The results are placed into the context of power generation, to give a ″well-to-wire″ (WtW) intensity. It was estimated that shale gas typically has a WtW emissions intensity about 1.8–2.4% higher than conventional gas, arising mainly from higher methane releases in well completion. Even using extreme assumptions, it was found that WtW emissions from shale gas need be no more than 15% higher than conventional gas if flaring or recovery measures are used. In all cases considered, the WtW emissions of shale gas powergen are significantly lower than those of coal. PMID:22085088

  19. Developments in greenhouse gas emissions and net energy use in Danish agriculture - How to achieve substantial CO{sub 2} reductions?

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, T., E-mail: tommy.dalgaard@agrsci.dk [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Olesen, J.E.; Petersen, S.O.; Petersen, B.M.; Jorgensen, U.; Kristensen, T.; Hutchings, N.J. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Gyldenkaerne, S. [Aarhus University, National Environmental Research Institute, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Hermansen, J.E. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark)

    2011-11-15

    Greenhouse gas (GHG) emissions from agriculture are a significant contributor to total Danish emissions. Consequently, much effort is currently given to the exploration of potential strategies to reduce agricultural emissions. This paper presents results from a study estimating agricultural GHG emissions in the form of methane, nitrous oxide and carbon dioxide (including carbon sources and sinks, and the impact of energy consumption/bioenergy production) from Danish agriculture in the years 1990-2010. An analysis of possible measures to reduce the GHG emissions indicated that a 50-70% reduction of agricultural emissions by 2050 relative to 1990 is achievable, including mitigation measures in relation to the handling of manure and fertilisers, optimization of animal feeding, cropping practices, and land use changes with more organic farming, afforestation and energy crops. In addition, the bioenergy production may be increased significantly without reducing the food production, whereby Danish agriculture could achieve a positive energy balance. - Highlights: > GHG emissions from Danish agriculture 1990-2010 are calculated, including carbon sequestration. > Effects of measures to further reduce GHG emissions are listed. > Land use scenarios for a substantially reduced GHG emission by 2050 are presented. > A 50-70% reduction of agricultural emissions by 2050 relative to 1990 is achievable. > Via bioenergy production Danish agriculture could achieve a positive energy balance. - Scenario studies of greenhouse gas mitigation measures illustrate the possible realization of CO{sub 2} reductions for Danish agriculture by 2050, sustaining current food production.

  20. Production of bio-gas from maize cobs

    Energy Technology Data Exchange (ETDEWEB)

    Leke, Luter [College of Physical Sciences, University of Aberdeen, AB24 3UE, Aberdeen (United Kingdom); Department of Chemistry, Benue State University, P M B 102119, Makurdi (Nigeria); Ogbanje, Anne Ada [Department of Chemistry, Benue State University, P M B 102119, Makurdi (Nigeria); Department of Renewable Energy, Energy Commission of Nigeria, Garki-Abuja (Nigeria); Terfa, Dekaa Henry [Department of Chemistry, Benue State University, P M B 102119, Makurdi (Nigeria); Ikyaagba, Tyoalumun [College of Physical Sciences, University of Aberdeen, AB24 3UE, Aberdeen (United Kingdom)

    2013-07-01

    Anaerobic digestion of energy crop residues and wastes is of increasing interest in order to reduce greenhouse gas emissions and to facilitate a sustainable development of energy supply. Production of biogas provides a versatile carrier of renewable energy, as methane can be used for replacement of fossil fuels in both heat and power generation as vehicle fuel. Biogas fuel production from blends of biological wastes such as Cow rumen liquor (CL), Poultry droppings (PD), and Goat Faeces (GF) with Maize cobs (M) were studied. 20 g of each inoculum was mixed with 100g of degraded maize cobs in the first three digesters while the fourth contained CL 10g, PD 10 g, and M 100 g. 100 g of M alone in the fifth digester served as the control. The blends were subjected to anaerobic digestion for 10 days on the prevailing atmospheric ambient temperature and pressure conditions. Physiochemical properties of the blends such as moisture content, crude protein, ash, fat, crude fibre, carbohydrate content, C/N ratio, and pH were also determined. Results of the daily performances of each system showed that maize cobs (M) alone had cumulative biogas yield of 1.50 cm3 while those of the blends (MCL, MPD, MGF and MCLPD) were 6.11 cm3, 3.05 cm3, 2.50 cm3, and 63.00 cm3 respectively, pH and C/N ratio affected the biogas yield of the systems significantly. These results indicate that the low biogas production from maize cobs can be enhanced significantly by blending with cow rumen liquor and poultry droppings.

  1. Extended lactations may improve cow health, productivity and reduce greenhouse gas emissions from organic dairy production

    DEFF Research Database (Denmark)

    Lehmann, Jesper Overgård; Mogensen, Lisbeth; Kristensen, Troels

    2014-01-01

    The concept of extended lactation is a break with the tradition of getting one calf per cow per year that should improve cow health, increase productivity and reduce greenhouse gas (GHG) emission per kg milk produced in high-yield organic dairy herds. These effects are achieved through fewer...... calvings per year and hence a production of fewer replacement heifers, which, in combination with fewer days dry per cow per year, will reduce the annual herd requirement for feed. Total herd feed use is a major determinant of GHG emission at farm gate. However, these effects also rely on the assumption...... will be able to produce milk for the same number of lactations and thus have longer, more productive lives. Additionally, cow health may be improved as the majority of diseases occur around calving. Increased productivity and improved cow health should also improve farm profitability, although fewer bull...

  2. Estimating Trends and Variation of Net Biome Productivity in India for 1980-2012 Using a Land Surface Model

    Science.gov (United States)

    Gahlot, Shilpa; Shu, Shijie; Jain, Atul K.; Baidya Roy, Somnath

    2017-11-01

    In this paper we explore the trend in net biome productivity (NBP) over India for the period 1980-2012 and quantify the impact of different environmental factors, including atmospheric CO2 concentrations ([CO2]), land use and land cover change, climate, and nitrogen deposition on carbon fluxes using a land surface model, Integrated Science Assessment Model. Results show that terrestrial ecosystems of India have been a carbon sink for this period. Driven by a strong CO2 fertilization effect, magnitude of NBP increased from 27.17 TgC/yr in the 1980s to 34.39 TgC/yr in the 1990s but decreased to 23.70 TgC/yr in the 2000s due to change in climate. Adoption of forest conservation, management, and reforestation policies in the past decade has promoted carbon sequestration in the ecosystems, but this effect has been offset by loss of carbon from ecosystems due to rising temperatures and decrease in precipitation.

  3. Spatial and seasonal characterization of net primary productivity and climate variables in southeastern China using MODIS data*

    Science.gov (United States)

    Peng, Dai-liang; Huang, Jing-feng; Huete, Alfredo R.; Yang, Tai-ming; Gao, Ping; Chen, Yan-chun; Chen, Hui; Li, Jun; Liu, Zhan-yu

    2010-01-01

    We developed a sophisticated method to depict the spatial and seasonal characterization of net primary productivity (NPP) and climate variables. The role of climate variability in the seasonal variation of NPP exerts delayed and continuous effects. This study expands on this by mapping the seasonal characterization of NPP and climate variables from space using geographic information system (GIS) technology at the pixel level. Our approach was developed in southeastern China using moderate-resolution imaging spectroradiometer (MODIS) data. The results showed that air temperature, precipitation and sunshine percentage contributed significantly to seasonal variation of NPP. In the northern portion of the study area, a significant positive 32-d lagged correlation was observed between seasonal variation of NPP and climate (Pair temperature, precipitation, and sunshine percentage, respectively (Pair temperature and precipitation on NPP lasted for 48 d or 64 d, while sunshine influence on NPP only persisted for 16 d. Due to complex topography and vegetation distribution in the southern part of the study region, the spatial patterns of vegetation-climate relationship became complicated and diversiform, especially for precipitation influences on NPP. In the northern part of the study area, all vegetation NPP had an almost similar response to seasonal variation of air temperature except for broad crops. The impacts of seasonal variation of precipitation and sunshine on broad and cereal crop NPP were slightly different from other vegetation NPP. PMID:20349524

  4. Assessing the impact of the urbanization process on net primary productivity in China in 1989-2000.

    Science.gov (United States)

    Tian, Guangjin; Qiao, Zhi

    2014-01-01

    Urban development affects the material circulation and energy flow of ecosystems, thereby affecting the Net Primary Productivity (NPP). The loss of NPP due to urban expansion was calculated integrating GLO-PEM with remote sensing and GIS techniques in China during the period of 1989-2000. Using urban expansion and the mean NPP for the different land use types in the fourteen regions, the total loss of NPP was calculated as 0.95 Tg C, which accounted for 0.03% of the national NPP of 1989. The total loss of NPP due to the transformation from cropland to urban land accounted for 91.93%, followed by forest (7.17%) and grassland (0.69%). However, the conversion from unused land, industrial and construction land, and water bodies to urban land resulted in an increase in the NPP. The regions locating in eastern China and middle China had large reductions in the total NPP due to urban expansion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Drought dominates the interannual variability in global terrestrial net primary production by controlling semi-arid ecosystems.

    Science.gov (United States)

    Huang, Ling; He, Bin; Chen, Aifang; Wang, Haiyan; Liu, Junjie; Lű, Aifeng; Chen, Ziyue

    2016-04-19

    Drought is a main driver of interannual variation in global terrestrial net primary production. However, how and to what extent drought impacts global NPP variability is unclear. Based on the multi-timescale drought index SPEI and a satellite-based annual global terrestrial NPP dataset, we observed a robust relationship between drought and NPP in both hemispheres. In the Northern Hemisphere, the annual NPP trend is driven by 19-month drought variation, whereas that in the Southern Hemisphere is driven by 16-month drought variation. Drought-dominated NPP, which mainly occurs in semi-arid ecosystems, explains 29% of the interannual variation in global NPP, despite its 16% contribution to total global NPP. More surprisingly, drought prone ecosystems in the Southern Hemisphere, which only account for 7% of the total global NPP, contribute to 33% of the interannual variation in global NPP. Our observations support the leading role of semi-arid ecosystems in interannual variability in global NPP and highlight the great impacts of long-term drought on the global carbon cycle.

  6. Variations in Vegetation Net Primary Production in the Qinghai-Xizang Plateau, China, from 1982 to 1999

    Energy Technology Data Exchange (ETDEWEB)

    Piao, S.; Fang, J.; He, J. [Department of Ecology, College of Environmental Science, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, 100871 (China)

    2006-01-15

    Vegetation net primary production (NPP) derived from a carbon model (Carnegie-Ames-Stanford Approach, CASA) and its interannual change in the Qinghai-Xizang (Tibetan) Plateau were investigated in this study using 1982-1999 time series data sets of normalized difference vegetation index (NDVI) and paired ground-based information on vegetation, climate, soil, and solar radiation. The 18-year averaged annual NPP over the plateau was 125 g C m-2 yr-1, decreasing from the southeast to the northwest, consistent with precipitation and temperature patterns. Total annual NPP was estimated between 0.183 and 0.244 Pg C over the 18 years, with an average of 0.212 Pg C (1 Pg = 1015 g). Two distinct periods (1982-1990 and 1991-1999) of NPP variation were observed, separated by a sharp reduction during 1990-1991. From 1982 to 1990, annual NPP did not show a significant trend, while from 1991 to 1999 a marked increase of 0.007 Pg C yr-2 was observed. NPP trends for most vegetation types resembled that of the whole plateau. The largest annual NPP increase during 1991-1999 appeared in alpine meadows, accounting for 32.3% of the increment of the whole region. Changes in solar radiation and temperature significantly influenced NPP variation, suggesting that solar radiation may be one of the major factors associated with changes in NPP.

  7. Effect of shading nets on the production and quality of blueberry fruit (Vaccinium corymbosum L. cv. Brigitta

    Directory of Open Access Journals (Sweden)

    Mario Marcelo Rodríguez Beraud

    2015-03-01

    Full Text Available Growth, development and fruit quality blueberry (Vaccinium corymbosum L. variety Brigitta under different shade nets were evaluated. Assays were performed in plants 7 years in a commercial orchard Collipulli, Araucanía Region, Chile. Treatments were a control without shading and four types of screens: a red 40% and 18% shade; aluminized mesh with 40% shade and a black mesh 35% shade. In fruits shade of red mesh 40% greater equatorial and polar diameter were observed and three weeks later harvested the fruits of treatment without mesh. In growing shade 40% aluminized mesh phenological stages extension lag and the maximum weekly production two weeks over control was observed. The highest yields were observed in plants of treatment and control shade of red mesh 40%, with 11008 kg ha-1 and 10461 kg ha-1, respectively, while the lowest was in red mesh 18% with 9668 kg ha-1. The fruits grown under shade of red mesh 18% showed the highest number of fruits per plant with 1806 berries per plant, fruit weight less than 1.69 g with the strongest with 3.76 N mm-1 module deformability. Therefore, the largest weight berry fruits observed in non-mesh screen and 40% red shading, together with the increased size and performance.

  8. Simulating Spatiotemporal Dynamics of Sichuan Grassland Net Primary Productivity Using the CASA Model and In Situ Observations

    Directory of Open Access Journals (Sweden)

    Chuanjiang Tang

    2014-01-01

    Full Text Available Net primary productivity (NPP is an important indicator for grassland resource management and sustainable development. In this paper, the NPP of Sichuan grasslands was estimated by the Carnegie-Ames-Stanford Approach (CASA model. The results were validated with in situ data. The overall precision reached 70%; alpine meadow had the highest precision at greater than 75%, among the three types of grasslands validated. The spatial and temporal variations of Sichuan grasslands were analyzed. The absorbed photosynthetic active radiation (APAR, light use efficiency (ε, and NPP of Sichuan grasslands peaked in August, which was a vigorous growth period during 2011. High values of APAR existed in the southwest regions in altitudes from 2000 m to 4000 m. Light use efficiency (ε varied in the different types of grasslands. The Sichuan grassland NPP was mainly distributed in the region of 3000–5000 m altitude. The NPP of alpine meadow accounted for 50% of the total NPP of Sichuan grasslands.

  9. Gas, water, and oil production from Wattenberg field in the Denver Basin, Colorado

    Science.gov (United States)

    Nelson, Philip H.; Santus, Stephen L.

    2011-01-01

    Gas, oil, and water production data were compiled from selected wells in two tight gas reservoirs-the Codell-Niobrara interval, comprised of the Codell Sandstone Member of the Carlile Shale and the Niobrara Formation; and the Dakota J interval, comprised mostly of the Muddy (J) Sandstone of the Dakota Group; both intervals are of Cretaceous age-in the Wattenberg field in the Denver Basin of Colorado. Production from each well is represented by two samples spaced five years apart, the first sample typically taken two years after production commenced, which generally was in the 1990s. For each producing interval, summary diagrams and tables of oil-versus-gas production and water-versus-gas production are shown with fluid-production rates, the change in production over five years, the water-gas and oil-gas ratios, and the fluid type. These diagrams and tables permit well-to-well and field-to-field comparisons. Fields producing water at low rates (water dissolved in gas in the reservoir) can be distinguished from fields producing water at moderate or high rates, and the water-gas ratios are quantified. The Dakota J interval produces gas on a per-well basis at roughly three times the rate of the Codell-Niobrara interval. After five years of production, gas data from the second samples show that both intervals produce gas, on average, at about one-half the rate as the first sample. Oil-gas ratios in the Codell-Niobrara interval are characteristic of a retrograde gas and are considerably higher than oil-gas ratios in the Dakota J interval, which are characteristic of a wet gas. Water production from both intervals is low, and records in many wells are discontinuous, particularly in the Codell-Niobrara interval. Water-gas ratios are broadly variable, with some of the variability possibly due to the difficulty of measuring small production rates. Most wells for which water is reported have water-gas ratios exceeding the amount that could exist dissolved in gas at reservoir

  10. Uncertainties in the development of unconventional gas production in the Netherlands

    NARCIS (Netherlands)

    Eker, S.; Van Daalen, C.

    2012-01-01

    Unconventional gas has raised debates all over the world following its considerable contribution to the natural gas production of some countries such as the US. The Netherlands, which is a prominent gas producer in the Western Europe, also considers unconventional resources as an alternative to

  11. Development of a low flow meter for measuring gas production in bioreactors

    Science.gov (United States)

    Accurate measurement of gas production from biological processes is important in many laboratory experiments. A gas flow rate measurement system, consisting of an embedded controller operating three gas meters, was developed to measure volumetric flows between 0 and 8 ml min-1 (1 atm, 273.15 K). The...

  12. Disentangling the Relationships between Net Primary Production and Precipitation in Southern Africa Savannas Using Satellite Observations from 1982 to 2010

    Directory of Open Access Journals (Sweden)

    Jane Southworth

    2013-08-01

    Full Text Available To obtain a better understanding of the variability in net primary production (NPP in savannas is important for the study of the global carbon cycle and the management of this particular ecosystem. Using satellite and precipitation data sets, we investigated the variations in NPP in southern African savannas from 1982 to 2010, and disentangled the relationships between NPP and precipitation by land cover classes and mean annual precipitation (MAP gradients. Specifically, we evaluate the utility of the third generation Global Inventory Monitoring and Modeling System (GIMMS3g normalized difference vegetation index (NDVI dataset, in comparison with Moderate-resolution Imaging Spectroradiometer (MODIS derived NPP products, and find strong relationships between the overlapping data periods (2000–2010, such that we can apply our model to derive NPP estimates to the full 29-year NDVI time-series. Generally, the northern portion of the study area is characterized by high NPP and low variability, whereas the southern portion is characteristic of low NPP and high variability. During the period 1982 through 2010, NPP has reduced at a rate of −2.13 g∙C∙m−2∙yr−1 (p < 0.1, corresponding to a decrease of 6.7% over 29 years, and about half of bush and grassland savanna has experienced a decrease in NPP. There is a significant positive relationship between mean annual NPP and MAP in bush and grassland savannas, but no significant relationship is observed in tree savannas. The relationship between mean annual NPP and MAP varies with increases in MAP, characterized as a linear relationship that breaks down when MAP exceeding around 850–900 mm.

  13. Reliability ensemble averaging of 21st century projections of terrestrial net primary productivity reduces global and regional uncertainties

    Science.gov (United States)

    Exbrayat, Jean-François; Bloom, A. Anthony; Falloon, Pete; Ito, Akihiko; Smallman, T. Luke; Williams, Mathew

    2018-02-01

    Multi-model averaging techniques provide opportunities to extract additional information from large ensembles of simulations. In particular, present-day model skill can be used to evaluate their potential performance in future climate simulations. Multi-model averaging methods have been used extensively in climate and hydrological sciences, but they have not been used to constrain projected plant productivity responses to climate change, which is a major uncertainty in Earth system modelling. Here, we use three global observationally orientated estimates of current net primary productivity (NPP) to perform a reliability ensemble averaging (REA) method using 30 global simulations of the 21st century change in NPP based on the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) business as usual emissions scenario. We find that the three REA methods support an increase in global NPP by the end of the 21st century (2095-2099) compared to 2001-2005, which is 2-3 % stronger than the ensemble ISIMIP mean value of 24.2 Pg C y-1. Using REA also leads to a 45-68 % reduction in the global uncertainty of 21st century NPP projection, which strengthens confidence in the resilience of the CO2 fertilization effect to climate change. This reduction in uncertainty is especially clear for boreal ecosystems although it may be an artefact due to the lack of representation of nutrient limitations on NPP in most models. Conversely, the large uncertainty that remains on the sign of the response of NPP in semi-arid regions points to the need for better observations and model development in these regions.

  14. Sodic soils reclaimed with by-product from flue gas desulfurization: corn production and soil quality.

    Science.gov (United States)

    Chun, S; Nishiyama, M; Matsumoto, S

    2001-01-01

    Interest is growing in the use of by-product from flue gas desulfurization (FGD) to reclaim sodic soils by controlling the pH and excessive Na+. This study evaluated the effects on corn (Zea mays) production and pH and electrical conductivity (EC) of calcareous sodic soil during four times of cultivation when the by-product was applied once at the first cultivation (Study I) and the impacts on plant and soil quality at first cultivation when the by-product was applied to the soil at 23,000 kg ha-1 (Study II). In Study I, the germination rate and corn production increased by applying the by-product (0, 5,800, 11,600, and 23,100 kg ha-1), and the greatest total amounts of corn production during the four times of cultivation was when the by-product was applied at 23,100 kg ha-1. In Study II, the pH, exchangeable sodium percentage (ESP), clay dispersion and soluble Na+ in the soil decreased and soluble Mg2+ and soluble K+ in the soil increased. The soil pH was reduced from 9.0 to 7.7 by applying the by-product. However, the by-product decreased the concentrations of total N and P in corn leaves in this study. No significant difference in the concentrations of Mo, Zn, Pb, Ni, Cd, Mn, Cr, Cu, and Al in corn leaves and the soil was observed between the by-product addition and the control except for B in the soil and Fe in corn leaves. The concentration of B in the soil was reduced from 28.7 mg kg-1 to 25.4 mg kg-1 and the concentration of Fe in corn leaves increased from 17.5 mg kg-1 to 22.6 mg kg-1 by applying the by-product in our study.

  15. Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

    Science.gov (United States)

    Guo, Chaohua; Wei, Mingzhen; Liu, Hong

    2015-01-01

    Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

  16. Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

    Directory of Open Access Journals (Sweden)

    Chaohua Guo

    Full Text Available Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

  17. NOy production, ozone loss and changes in net radiative heating due to energetic particle precipitation in 2002–2010

    Directory of Open Access Journals (Sweden)

    M. Sinnhuber

    2018-01-01

    Full Text Available We analyze the impact of energetic particle precipitation on the stratospheric nitrogen budget, ozone abundances and net radiative heating using results from three global chemistry-climate models considering solar protons and geomagnetic forcing due to auroral or radiation belt electrons. Two of the models cover the atmosphere up to the lower thermosphere, the source region of auroral NO production. Geomagnetic forcing in these models is included by prescribed ionization rates. One model reaches up to about 80 km, and geomagnetic forcing is included by applying an upper boundary condition of auroral NO mixing ratios parameterized as a function of geomagnetic activity. Despite the differences in the implementation of the particle effect, the resulting modeled NOy in the upper mesosphere agrees well between all three models, demonstrating that geomagnetic forcing is represented in a consistent way either by prescribing ionization rates or by prescribing NOy at the model top.Compared with observations of stratospheric and mesospheric NOy from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS instrument for the years 2002–2010, the model simulations reproduce the spatial pattern and temporal evolution well. However, after strong sudden stratospheric warmings, particle-induced NOy is underestimated by both high-top models, and after the solar proton event in October 2003, NOy is overestimated by all three models. Model results indicate that the large solar proton event in October 2003 contributed about 1–2 Gmol (109 mol NOy per hemisphere to the stratospheric NOy budget, while downwelling of auroral NOx from the upper mesosphere and lower thermosphere contributes up to 4 Gmol NOy. Accumulation over time leads to a constant particle-induced background of about 0.5–1 Gmol per hemisphere during solar minimum, and up to 2 Gmol per hemisphere during solar maximum. Related negative anomalies of ozone are predicted by

  18. Modeling of Carbon Sequestration on Eucalyptus Plantation in Brazililian Cerrado Region for Better Characterization of Net Primary Productivity

    Science.gov (United States)

    Echeverri, J. D.; Siqueira, M. B.

    2013-05-01

    Managed Forests have important roles in climate change due to their contribution to CO2 sequestration stored in their biomass, soils and products therefrom. Terrestrial net primary production (NPP, kgC/m2), equal to gross primary production minus autotrophic respiration, represents the carbon available for plant allocation to leaves, stems, roots, defensive compounds, and reproduction and is the basic measure of biological productivity. Tree growth, food production, fossil fuel production, and atmospheric CO2 levels are all strongly controlled by NPP. Accurate quantification of NPP at local to global scales is therefore central topic for carbon cycle researchers, foresters, land and resource managers, and politicians. For recent or current NPP estimates, satellite remote sensing can be used but for future climate scenarios, simulation models are required. There is an increasing trend to displace natural Brazilian Cerrado to Eucalyptus for paper mills and energy conversion from biomass. The objective of this research exercise is to characterize NPP from managed Eucalyptus plantation in the Brazilian Cerrado. The models selected for this study were the 3-PG and Biome-BGC. The selection of these models aims to cover a range of complexity that allow the evaluation of the processes modeled as to its relevance to a best estimate of productivity in eucalyptus forests. 3-PG model is the simplest of the models chosen for this exercise. Its main purpose is to estimate productivity of forests in timber production. The model uses the relationship of quantum efficiency in the transformation of light energy into biomass for vegetative growth calculations in steps in time of one month. Adverse weather conditions are treated with reduction factors applied in the top efficiency. The second model is the Biome-BGC that uses biology and geochemistry principles to estimate leaf-level photosynthesis based on limiting factors such as availability of light and nutrient constraints. The

  19. Estimates of Global Rangeland Net Primary Productivity and its Consumption Based on Climate and Livestock Distribution Data

    Science.gov (United States)

    Asrar, G.; Wolf, J.; Rafique, R.; West, T. O.; Ogle, S. M.

    2016-12-01

    Rangelands play an important role in providing ecosystem services such as food, forage, and fuels in many parts of the world. The net primary productivity (NPP), a difference between CO2 fixed by plants and CO2 lost to autotrophic respiration, is a good indicator of the productivity of rangeland ecosystems, and their contribution to the cycling of carbon in the Earth system. In this study, we estimated the NPP of global rangelands, the consumption thereof by grazing livestock, and associated uncertainties, to better understand and quantify the contribution of rangelands to land-based carbon storage. We estimated rangeland NPP using mean annual precipitation data from Climate Research Unit (CRU), and a regression model based on global observations (Del Grosso et al., 2008). Spatial distributions of annual livestock consumption of rangeland NPP (Wolf et al., 2015) were combined with gridded annual rangeland NPP for the years 2000 - 2011. The uncertainty analysis of these estimates was conducted using a Monte Carlo approach. The rangeland NPP estimates with associated uncertainties were also compared with the total modeled GPP estimates obtained from vegetation dynamic model simulations. Our results showed that mean above-ground NPP of rangelands is 1017.5 MgC/km2, while mean below-ground NPP is 847.6 MgC/km2. The total rangeland NPP represents a significant portion of the total NPP of the terrestrial ecosystem. The livestock area requirements used to geographically distribute livestock spatially are based on optimal pasturage and are low relative to area requirements on less productive land. Even so, ca. 90% of annual livestock consumption of rangeland NPP were met with no adjustment of livestock distributions. Moreover, the results of this study allowed us to explicitly quantify the temporal and spatial variations of rangeland NPP under different climatic conditions. Uncertainty analysis was helpful in identifying the strength and weakness of the methods used to

  20. Hydrogen production by absorption enhanced water gas shift (AEWGS)

    Energy Technology Data Exchange (ETDEWEB)

    Escobedo Bretado, Miguel A. [Facultad de Ciencias Quimicas, Universidad Juarez del Estado de Durango, Ave. Veterinaria s/n, Circuito Universitario, Durango 34120 (Mexico); Departamento de Quimica de Materiales, Centro de Investigacion en Materiales Avanzados, S.C. Miguel de Cervantes 120, Chihuahua, Chih. 31109 (Mexico); Delgado Vigil, Manuel D.; Gutierrez, Jesus Salinas; Lopez Ortiz, Alejandro; Collins-Martinez, Virginia [Departamento de Quimica de Materiales, Centro de Investigacion en Materiales Avanzados, S.C. Miguel de Cervantes 120, Chihuahua, Chih. 31109 (Mexico)

    2010-11-15

    AEWGS is a reaction that combines the WGS reaction and CO{sub 2} capture by a solid absorbent to produce high purity H{sub 2} from synthesis gas in one single step at 600-800 C. This reactor system, if homogeneous, would not require a catalyst. However, previous research on this concept was not conclusive, since a steel reactor was used and reactor walls were suspected to act as catalyst. Therefore, there is a need to address this issue and to select and evaluate suitable CO{sub 2} absorbents for this concept. AEWGS was studied using a quartz-made fixed-bed reactor at; SV = 3000 h{sup -1}, feed; 5% CO, 15% H{sub 2}O, balance He-N{sub 2} at 600 C, 1 atm. CO{sub 2} absorbents tested were CaO*MgO, and Na{sub 2}ZrO{sub 3}. Empty quartz-reactor tests leaded to conclude that a catalyst is needed for the WGS at temperatures of interest. A 97% H{sub 2} product was obtained with calcined dolomite suggesting this last to act as a WGS catalyst. (author)

  1. De-coupling of net community production and new production in the euphotic zone of the equatorial Pacific: A model study

    Science.gov (United States)

    Wang, Xiujun; Murtugudde, Ragu; Busalacchi, Antonio J.; Le Borgne, Robert

    2005-11-01

    A physical-biogeochemical model is employed to estimate rates of nitrogen based primary production (PP*), net community production (NCP*), and new production (NP) in the equatorial Pacific. The model reproduces observed vertical differences between ammonium regeneration and uptake: uptake > regeneration above 40 m and uptake < regeneration below 40 m. As a result, NCP* exceeds NP in the upper 40 m, but decreases more rapidly with depth than NP. High surface NCP* appears across the entire upwelling region whereas high surface NP is found in the eastern equatorial Pacific with a much stronger spatial and temporal variability in NCP* relative to NP. The NCP*/PP* ratio shows a larger range (0.1-0.4) than the f-ratio (i.e., the NP/PP* ratio) (0.1-0.3). The zonal and vertical de-coupling between NCP* and NP is caused by the time lag between biological uptake and regeneration, and the advection of organic and inorganic nitrogen. The excess of NCP* over NP in the upper euphotic zone suggests the possibility of carbon over-consumption in the upper ocean of the equatorial Pacific with implications for predicting sinks/sources of CO2.

  2. Optimal Pretreatment System of Flowback Water from Shale Gas Production

    OpenAIRE

    Carrero-Parreño, Alba; Onishi, Viviani C.; Salcedo Díaz, Raquel; Ruiz-Femenia, Rubén; Fraga, Eric S.; Caballero, José A.; Reyes-Labarta, Juan A.

    2017-01-01

    Shale gas has emerged as a potential resource to transform the global energy market. Nevertheless, gas extraction from tight shale formations is only possible after horizontal drilling and hydraulic fracturing, which generally demand large amounts of water. Part of the ejected fracturing fluid returns to the surface as flowback water, containing a variety of pollutants. For this reason, water reuse and water recycling technologies have received further interest for enhancing overall shale gas...

  3. Evaluation of gas production potential from gas hydrate deposits in National Petroleum Reserve Alaska using numerical simulations

    Science.gov (United States)

    Nandanwar, Manish S.; Anderson, Brian J.; Ajayi, Taiwo; Collett, Timothy S.; Zyrianova, Margarita V.

    2016-01-01

    An evaluation of the gas production potential of Sunlight Peak gas hydrate accumulation in the eastern portion of the National Petroleum Reserve Alaska (NPRA) of Alaska North Slope (ANS) is conducted using numerical simulations, as part of the U.S. Geological Survey (USGS) gas hydrate Life Cycle Assessment program. A field scale reservoir model for Sunlight Peak is developed using Advanced Processes & Thermal Reservoir Simulator (STARS) that approximates the production design and response of this gas hydrate field. The reservoir characterization is based on available structural maps and the seismic-derived hydrate saturation map of the study region. A 3D reservoir model, with heterogeneous distribution of the reservoir properties (such as porosity, permeability and vertical hydrate saturation), is developed by correlating the data from the Mount Elbert well logs. Production simulations showed that the Sunlight Peak prospect has the potential of producing 1.53 × 109 ST m3 of gas in 30 years by depressurization with a peak production rate of around 19.4 × 104 ST m3/day through a single horizontal well. To determine the effect of uncertainty in reservoir properties on the gas production, an uncertainty analysis is carried out. It is observed that for the range of data considered, the overall cumulative production from the Sunlight Peak will always be within the range of ±4.6% error from the overall mean value of 1.43 × 109 ST m3. A sensitivity analysis study showed that the proximity of the reservoir from the base of permafrost and the base of hydrate stability zone (BHSZ) has significant effect on gas production rates. The gas production rates decrease with the increase in the depth of the permafrost and the depth of BHSZ. From the overall analysis of the results it is concluded that Sunlight Peak gas hydrate accumulation behaves differently than other Class III reservoirs (Class III reservoirs are composed of a single layer of hydrate with no

  4. Environmental benefits of advanced oil and gas exploration and production technology

    Energy Technology Data Exchange (ETDEWEB)

    None

    1999-10-01

    THROUGHOUT THE OIL AND GAS LIFE CYCLE, THE INDUSTRY HAS APPLIED AN ARRAY OF ADVANCED TECHNOLOGIES TO IMPROVE EFFICIENCY, PRODUCTIVITY, AND ENVIRONMENTAL PERFORMANCE. THIS REPORT FOCUSES SPECIFICALLY ON ADVANCES IN EXPLORATION AND PRODUCTION (E&P) OPERATIONS.

  5. Remote and Onsite Direct Measurements of Emissions from Oil and Natural Gas Production

    Science.gov (United States)

    Environmentally responsible oil and gas production requires accurate knowledge of emissions from long-term production operations1, which can include methane, volatile organic compounds, and hazardous air pollutants. Well pad emissions vary based on the geologically-determined com...

  6. Report on simulation of fission gas and fission product diffusion in UO2

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Anders David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Perriot, Romain Thibault [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Pastore, Giovanni [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Tonks, Michael R. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Cooper, Michael William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Liu, Xiang-Yang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Goyal, Anuj [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Uberuaga, Blas P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Stanek, Christopher Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division

    2016-07-22

    In UO2 nuclear fuel, the retention and release of fission gas atoms such as xenon (Xe) are important for nuclear fuel performance by, for example, reducing the fuel thermal conductivity, causing fuel swelling that leads to mechanical interaction with the clad, increasing the plenum pressure and reducing the fuel–clad gap thermal conductivity. We use multi-­scale simulations to determine fission gas diffusion mechanisms as well as the corresponding rates in UO2 under both intrinsic and irradiation conditions. In addition to Xe and Kr, the fission products Zr, Ru, Ce, Y, La, Sr and Ba have been investigated. Density functional theory (DFT) calculations are used to study formation, binding and migration energies of small clusters of Xe atoms and vacancies. Empirical potential calculations enable us to determine the corresponding entropies and attempt frequencies for migration as well as investigate the properties of large clusters or small fission gas bubbles. A continuum reaction-­diffusion model is developed for Xe and point defects based on the mechanisms and rates obtained from atomistic simulations. Effective fission gas diffusivities are then obtained by solving this set of equations for different chemical and irradiation conditions using the MARMOT phase field code. The predictions are compared to available experimental data. The importance of the large XeU3O cluster (a Xe atom in a uranium + oxygen vacancy trap site with two bound uranium vacancies) is emphasized, which is a consequence of its high mobility and high binding energy. We find that the XeU3O cluster gives Xe diffusion coefficients that are higher for intrinsic conditions than under irradiation over a wide range of temperatures. Under irradiation the fast-­moving XeU3O cluster recombines quickly with irradiation-induced interstitial U ions, while this mechanism is less important for intrinsic conditions. The net result is higher

  7. Biogenic carbon fluxes from global agricultural production and consumption: Gridded, annual estimates of net ecosystem carbon exchange

    Science.gov (United States)

    Wolf, J.; West, T. O.; le Page, Y.; Thomson, A. M.

    2014-12-01

    Quantification of biogenic carbon fluxes from agricultural lands is needed to generate globally consistent bottom-up estimates for carbon monitoring and model input. We quantify agricultural carbon fluxes associated with annual (starting in 1961) crop net primary productivity (NPP), harvested biomass, and human and livestock consumption and emissions, with estimates of uncertainty, by applying region- and species-specific carbon parameters to annual crop, livestock, food and trade inventory data, and generate downscaled, gridded (0.05 degree resolution) representations of these fluxes. In 2011, global crop NPP was 5.25 ± 0.46 Pg carbon (excluding root exudates), of which 2.05 ± 0.051 Pg carbon was harvested as primary crops; an additional 0.54 Pg of crop residue carbon was collected for livestock fodder. In 2011, total livestock feed intake was 2.42 ± 0.21 Pg carbon, of which 2.31 ± 0.21 Pg carbon was emitted as carbon dioxide and 0.072 ± 0.005 Pg carbon was emitted as methane. We estimate that livestock grazed 1.18 Pg carbon from non-crop lands in 2011, representing 48.5 % of global total feed intake. In 2009, the latest available data year, we estimate global human food intake (excluding seafood and orchard fruits and nuts) at 0.52 ± 0.03 Pg carbon, with an additional 0.24 ± 0.01 Pg carbon of food supply chain losses. Trends in production and consumption of agricultural carbon between 1961 and recent years, such as increasing dominance of oilcrops and decreasing percent contribution of pasturage to total livestock feed intake, are discussed, and accounting of all agricultural carbon was done for the years 2005 and 2009. Gridded at 0.05 degree resolution, these quantities represent local uptake and release of agricultural biogenic carbon (e.g. biomass production and removal, residue and manure inputs to soils) and may be used with other gridded data to help estimate current and future changes in soil organic carbon.

  8. Characterizing Spatial Variability of Ice Algal Chlorophyll a and Net Primary Production between Sea Ice Habitats Using Horizontal Profiling Platforms

    Directory of Open Access Journals (Sweden)

    Benjamin A. Lange

    2017-11-01

    Full Text Available Assessing the role of sea ice algal biomass and primary production for polar ecosystems remains challenging due to the strong spatio-temporal variability of sea ice algae. Therefore, the spatial representativeness of sea ice algal biomass and primary production sampling remains a key issue in large-scale models and climate change predictions of polar ecosystems. To address this issue, we presented two novel approaches to up-scale ice algal chl a biomass and net primary production (NPP estimates based on profiles covering distances of 100 to 1,000 s of meters. This was accomplished by combining ice core-based methods with horizontal under-ice spectral radiation profiling conducted in the central Arctic Ocean during summer 2012. We conducted a multi-scale comparison of ice-core based ice algal chl a biomass with two profiling platforms: a remotely operated vehicle and surface and under ice trawl (SUIT. NPP estimates were compared between ice cores and remotely operated vehicle surveys. Our results showed that ice core-based estimates of ice algal chl a biomass and NPP do not representatively capture the spatial variability compared to the remotely operated vehicle-based estimates, implying considerable uncertainties for pan-Arctic estimates based on ice core observations alone. Grouping sea ice cores based on region or ice type improved the representativeness. With only a small sample size, however, a high risk of obtaining non-representative estimates remains. Sea ice algal chl a biomass estimates based on the dominant ice class alone showed a better agreement between ice core and remotely operated vehicle estimates. Grouping ice core measurements yielded no improvement in NPP estimates, highlighting the importance of accounting for the spatial variability of both the chl a biomass and bottom-ice light in order to get representative estimates. Profile-based measurements of ice algae chl a biomass identified sea ice ridges as an underappreciated

  9. Comparison of Aerial and Terrestrial Remote Sensing Techniques for Quantifying Forest Canopy Structural Complexity and Estimating Net Primary Productivity

    Science.gov (United States)

    Fahey, R. T.; Tallant, J.; Gough, C. M.; Hardiman, B. S.; Atkins, J.; Scheuermann, C. M.

    2016-12-01

    Canopy structure can be an important driver of forest ecosystem functioning - affecting factors such as radiative transfer and light use efficiency, and consequently net primary production (NPP). Both above- (aerial) and below-canopy (terrestrial) remote sensing techniques are used to assess canopy structure and each has advantages and disadvantages. Aerial techniques can cover large geographical areas and provide detailed information on canopy surface and canopy height, but are generally unable to quantitatively assess interior canopy structure. Terrestrial methods provide high resolution information on interior canopy structure and can be cost-effectively repeated, but are limited to very small footprints. Although these methods are often utilized to derive similar metrics (e.g., rugosity, LAI) and to address equivalent ecological questions and relationships (e.g., link between LAI and productivity), rarely are inter-comparisons made between techniques. Our objective is to compare methods for deriving canopy structural complexity (CSC) metrics and to assess the capacity of commonly available aerial remote sensing products (and combinations) to match terrestrially-sensed data. We also assess the potential to combine CSC metrics with image-based analysis to predict plot-based NPP measurements in forests of different ages and different levels of complexity. We use combinations of data from drone-based imagery (RGB, NIR, Red Edge), aerial LiDAR (commonly available medium-density leaf-off), terrestrial scanning LiDAR, portable canopy LiDAR, and a permanent plot network - all collected at the University of Michigan Biological Station. Our results will highlight the potential for deriving functionally meaningful CSC metrics from aerial imagery, LiDAR, and combinations of data sources. We will also present results of modeling focused on predicting plot-level NPP from combinations of image-based vegetation indices (e.g., NDVI, EVI) with LiDAR- or image-derived metrics of

  10. Effects of nitrogen application rates on net annual global warming potential and greenhouse gas intensity in double-rice cropping systems of the Southern China.

    Science.gov (United States)

    Chen, Zhongdu; Chen, Fu; Zhang, Hailin; Liu, Shengli

    2016-12-01

    The net global warming potential (NGWP) and net greenhouse gas intensity (NGHGI) of double-rice cropping systems are not well documented. We measured the NGWP and NGHGI including soil organic carbon (SOC) change and indirect emissions (IE) from double-crop rice fields with fertilizing systems in Southern China. These experiments with three different nitrogen (N) application rates since 2012 are as follows: 165 kgN ha -1 for early rice and 225 kgN ha -1 for late rice (N1), which was the local N application rates as the control; 135 kgN ha -1 for early rice and 180 kgN ha -1 for late rice (N2, 20 % reduction); and 105 kgN ha -1 for early rice and 135 kgN ha -1 for late rice (N3, 40 % reduction). Results showed that yields increased with the increase of N application rate, but without significant difference between N1 and N2 plots. Annual SOC sequestration rate under N1 was estimated to be 1.15 MgC ha -1  year -1 , which was higher than those under other fertilizing systems. Higher N application tended to increase CH 4 emissions during the flooded rice season and significantly increased N 2 O emissions from drained soils during the nonrice season, ranking as N1 > N2 > N3 with significant difference (P < 0.05). Two-year average IE has a huge contribution to GHG emissions mainly coming from the higher N inputs in the double-rice cropping system. Reducing N fertilizer usage can effectively decrease the NGWP and NGHGI in the double-rice cropping system, with the lowest NGHGI obtained in the N2 plot (0.99 kg CO 2 -eq kg -1 yield year -1 ). The results suggested that agricultural economic viability and GHG mitigation can be simultaneously achieved by properly reducing N fertilizer application in double-rice cropping systems.

  11. High efficient ethanol and VFA production from gas fermentation: effect of acetate, gas and inoculum microbial composition

    DEFF Research Database (Denmark)

    El-Gammal, Maie; Abou-Shanab, Reda; Angelidaki, Irini

    2017-01-01

    In bioindustry, syngas fermentation is a promising technology for biofuel production without the use of plant biomass as sugar-based feedstock. The aim of this study was to identify optimal conditions for high efficient ethanol and volatile fatty acids (VFA) production from synthetic gas...... fermentation. Therefore, the effect of different gases (pure CO, H2, and a synthetic syngas mixture), media (acetate medium and acetate-free medium), and biocatalyst (pure and mixed culture) were studied. Acetate was the most dominant product independent on inoculum type. The maximum concentration of volatile...... fatty acids and ethanol was achieved by the pure culture (Clostridium ragsdalei). Depending on the headspace gas composition, VFA concentrations were up to 300% higher after fermentation with Clostridium ragsdalei compared to fermentation with mixed culture. The preferred gas composition with respect...

  12. Relationship between in situ degradation kinetics and in vitro gas production fermentation using different mathematical models

    NARCIS (Netherlands)

    Rodrigues, M.A.M.; Cone, J.W.; Ferreira, L.M.M.; Blok, M.C.; Guedes, C.

    2009-01-01

    In vitro and in situ studies were conducted to evaluate the influence of different mathematical models, used to fit gas production profiles of 15 feedstuffs, on estimates of nylon bag organic matter (OM) degradation kinetics. The gas production data were fitted to Exponential, Logistic, Gompertz and

  13. 21 CFR 886.5918 - Rigid gas permeable contact lens care products.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Rigid gas permeable contact lens care products. 886.5918 Section 886.5918 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5918 Rigid gas permeable contact lens care products. (a)...

  14. Different palm oil production systems for energy purposes and their greenhouse gas implications

    NARCIS (Netherlands)

    Wicke, B.|info:eu-repo/dai/nl/306645955; Dornburg, V.|info:eu-repo/dai/nl/189955007; Junginger, H.M.|info:eu-repo/dai/nl/202130703; Faaij, A.P.C.|info:eu-repo/dai/nl/10685903X

    2008-01-01

    This study analyses the greenhouse gas (GHG) emissions of crude palm oil (CPO) and palm fatty acid distillate (PFAD) production in northern Borneo (Malaysia), their transport to the Netherlands and their co-firing with natural gas for electricity production. In the case of CPO, conversion to

  15. Evaluated displacement and gas production cross-sections for materials irradiated with intermediate energy nucleons

    Directory of Open Access Journals (Sweden)

    Konobeyev Alexander Yu.

    2017-01-01

    Full Text Available Atomic displacement and gas production cross-sections were obtained for a number of materials to calculate radiation damage and gas production rate in nuclear- and fusion reactors, and neutron spallation sources. An advanced atomistic modelling approach was applied for calculations of the number of stable displacements in materials.

  16. Demonstrating multi-layered MAS in control of offshore oil and gas production

    DEFF Research Database (Denmark)

    Lindegaard Mikkelsen, Lars; Næumann, J. R.; Demazeau, Y.

    2013-01-01

    From a control perspective, offshore oil and gas production is very challenging due to the many and potentially conflicting production objectives that arise from the intrinsic complexity of the oil and gas domain. In this paper, we demonstrate how a multi-layered multi-agent system can be used...

  17. Multi-layered satisficing decision making in oil and gas production platforms

    DEFF Research Database (Denmark)

    Lindegaard Mikkelsen, Lars; Demazeau, Yves; Jørgensen, B. N.

    2013-01-01

    From a control perspective, offshore oil and gas production is very challenging due to the many and potentially conflicting production objectives that arise from the intrinsic complexity of the oil and gas domain. In this paper, we show how a multi-layered multi-agent system can be used...

  18. In vitro organic matter digestibility and gas production of fish-meal ...

    African Journals Online (AJOL)

    In this study, an in vitro rumen gas production technique was utilized to evaluate fish-meal coated with different types and levels of fats for total gas production, Metabolizable energy (ME) and organic matter digestibility (OMD) contents. Approximately 200 mg of sample was weighed and inserted in glass syringes, then ...

  19. [Parameter sensitivity of simulating net primary productivity of Larix olgensis forest based on BIOME-BGC model].

    Science.gov (United States)

    He, Li-hong; Wang, Hai-yan; Lei, Xiang-dong

    2016-02-01

    Model based on vegetation ecophysiological process contains many parameters, and reasonable parameter values will greatly improve simulation ability. Sensitivity analysis, as an important method to screen out the sensitive parameters, can comprehensively analyze how model parameters affect the simulation results. In this paper, we conducted parameter sensitivity analysis of BIOME-BGC model with a case study of simulating net primary productivity (NPP) of Larix olgensis forest in Wangqing, Jilin Province. First, with the contrastive analysis between field measurement data and the simulation results, we tested the BIOME-BGC model' s capability of simulating the NPP of L. olgensis forest. Then, Morris and EFAST sensitivity methods were used to screen the sensitive parameters that had strong influence on NPP. On this basis, we also quantitatively estimated the sensitivity of the screened parameters, and calculated the global, the first-order and the second-order sensitivity indices. The results showed that the BIOME-BGC model could well simulate the NPP of L. olgensis forest in the sample plot. The Morris sensitivity method provided a reliable parameter sensitivity analysis result under the condition of a relatively small sample size. The EFAST sensitivity method could quantitatively measure the impact of simulation result of a single parameter as well as the interaction between the parameters in BIOME-BGC model. The influential sensitive parameters for L. olgensis forest NPP were new stem carbon to new leaf carbon allocation and leaf carbon to nitrogen ratio, the effect of their interaction was significantly greater than the other parameter' teraction effect.

  20. Sensitivity of boreal forest regional water flux and net primary production simulations to sub-grid-scale land cover complexity

    Science.gov (United States)

    Kimball, J. S.; Running, S. W.; Saatchi, S. S.

    1999-11-01

    We use a general ecosystem process model (BIOME-BGC) coupled with remote sensing information to evaluate the sensitivity of boreal forest regional evapotranspiration (ET) and net primary production (NPP) to land cover spatial scale. Simulations were conducted over a 3 year period (1994-1996) at spatial scales ranging from 30 to 50 km within the BOREAS southern modeling subarea. Simulated fluxes were spatially complex, ranging from 0.1 to 3.9 Mg C ha-1 yr-1 and from 18 to 29 cm yr-1. Biomass and leaf area index heterogeneity predominantly controlled this complexity, while biophysical differences between deciduous and coniferous vegetation were of secondary importance. Spatial aggregation of land cover characteristics resulted in mean monthly NPP estimation bias from 25 to 48% (0.11-0.20 g C m-2 d-1) and annual estimation errors from 2 to 14% (0.04-0.31 Mg C ha-1 yr-1). Error was reduced at longer time intervals because coarse scale overestimation errors during spring were partially offset by underestimation of fine scale results during summer and winter. ET was relatively insensitive to land cover spatial scale with an average bias of less than 5% (0.04 kg m-2 d-1). Factors responsible for differences in scaling behavior between ET and NPP included compensating errors for ET calculations and boreal forest spatial and temporal NPP complexity. Careful consideration of landscape spatial and temporal heterogeneity is necessary to identify and mitigate potential error sources when using plot scale information to understand regional scale patterns. Remote sensing data integrated within an ecological process model framework provides an efficient mechanism to evaluate scaling behavior, interpret patterns in coarse resolution data, and identify appropriate scales of operation for various processes.

  1. Evaluating spatial-temporal dynamics of net primary productivity of different forest types in northeastern China based on improved FORCCHN.

    Directory of Open Access Journals (Sweden)

    Junfang Zhao

    Full Text Available An improved individual-based forest ecosystem carbon budget model for China (FORCCHN was applied to investigate the spatial-temporal dynamics of net primary productivity of different forest types in northeastern China. In this study, the forests of northeastern China were categorized into four ecological types according to their habitats and generic characteristics (evergreen broadleaf forest, deciduous broadleaf forest, evergreen needleleaf forest and deciduous needleleaf forest. The results showed that distribution and change of forest NPP in northeastern China were related to the different forest types. From 1981 to 2002, among the forest types in northeastern China, per unit area NPP and total NPP of deciduous broadleaf forest were the highest, with the values of 729.4 gC/(m(2•yr and 106.0 TgC/yr, respectively, followed by mixed broadleaf- needleleaf forest, deciduous needleleaf forest and evergreen needleleaf forest. From 1981 to 2002, per unit area NPP and total NPP of different forest types in northeastern China exhibited significant trends of interannual increase, and rapid increase was found between the 1980s and 1990s. The contribution of the different forest type's NPP to total NPP in northeastern China was clearly different. The greatest was deciduous broadleaf forest, followed by mixed broadleaf- needleleaf forest and deciduous needleleaf forest. The smallest was evergreen needleleaf forest. Spatial difference in NPP between different forest types was remarkable. High NPP values of deciduous needleleaf forest, mixed broadleaf- needleleaf forest and deciduous broadleaf forest were found in the Daxing'anling region, the southeastern of Xiaoxing'anling and Jilin province, and the Changbai Mountain, respectively. However, no regional differences were found for evergreen needleleaf NPP. This study provided not only an estimation NPP of different forest types in northeastern China but also a useful methodology for estimating forest

  2. Temporal variability and drivers of net ecosystem production of a Turkey oak forest in Italy under coppice management

    Science.gov (United States)

    Belelli Marchesini, Luca; Rey, Ana; Papale, Dario; Valentini, Riccardo

    2010-05-01

    The progress in the understanding of the carbon exchange between forests and the atmosphere has been dramatic over the last few years, yet largely based on observations of middle-aged or mature stands in the temperate and boreal region while quite a few studies report on the temporal dynamics of carbon balance in forest stand chronosequences taking into account the effect of forest management (Law et al., 2003; Kowalski et al., 2003; Kolari et al, 2004; Zha et al., 2009). In order to quantify the temporal variability of CO2 fluxes at ecosystem level following coppicing, we analyze eddy covariance data of a deciduous oak (Quercus cerris L.) coppice forest in central Italy (Roccarespampani, VT) collected over two differently aged forest stands in the period 2000-2006 and covering most of the rotation period (0-6; 11-15 years). Data processing was performed evenly for whole data-set according to the CarboEurope database standard (Papale et al., 2006). The inter-annual variability and seasonal dynamics of net ecosystem exchange (NEE), partitioned into ecosystem respiration (Reco) and gross primary production (GPP), were analyzed looking at the relationships with the main structural (biomass) and environmental drivers (air and soil temperature, precipitation, soil water content, vapour pressure deficit, global radiation) to understand which factors control the carbon dynamics of these intensively managed forests After harvesting the forest acted as a carbon source of 69 gC m-2, while in the following years NEE ranged from -18.9 (stand age: 2 years) to -1077.9 g C m-2yr-1 (stand age: 15 years). Evidently the ecosystem promptly recovers its carbon sink capacity already in the years shortly after the harvest and increases its carbon sequestration capacity with stand age (R2= 0.75, P

  3. Gas-Solid Reaction Route toward the Production of Intermetallics from Their Corresponding Oxide Mixtures

    Directory of Open Access Journals (Sweden)

    Hesham Ahmed

    2016-08-01

    Full Text Available Near-net shape forming of metallic components from metallic powders produced in situ from reduction of corresponding pure metal oxides has not been explored to a large extent. Such a process can be probably termed in short as the “Reduction-Sintering” process. This methodology can be especially effective in producing components containing refractory metals. Additionally, in situ production of metallic powder from complex oxides containing more than one metallic element may result in in situ alloying during reduction, possibly at lower temperatures. With this motivation, in situ reduction of complex oxides mixtures containing more than one metallic element has been investigated intensively over a period of years in the department of materials science, KTH, Sweden. This review highlights the most important features of that investigation. The investigation includes not only synthesis of intermetallics and refractory metals using the gas solid reaction route but also study the reaction kinetics and mechanism. Environmentally friendly gases like H2, CH4 and N2 were used for simultaneous reduction, carburization and nitridation, respectively. Different techniques have been utilized. A thermogravimetric analyzer was used to accurately control the process conditions and obtain reaction kinetics. The fluidized bed technique has been utilized to study the possibility of bulk production of intermetallics compared to milligrams in TGA. Carburization and nitridation of nascent formed intermetallics were successfully carried out. A novel method based on material thermal property was explored to track the reaction progress and estimate the reaction kinetics. This method implies the dynamic measure of thermal diffusivity using laser flash method. These efforts end up with a successful preparation of nanograined intermetallics like Fe-Mo and Ni-W. In addition, it ends up with simultaneous reduction and synthesis of Ni-WN and Ni-WC from their oxide mixtures

  4. Potential biodefense model applications for portable chlorine dioxide gas production.

    Science.gov (United States)

    Stubblefield, Jeannie M; Newsome, Anthony L

    2015-01-01

    Development of decontamination methods and strategies to address potential infectious disease outbreaks and bioterrorism events are pertinent to this nation's biodefense strategies and general biosecurity. Chlorine dioxide (ClO2) gas has a history of use as a decontamination agent in response to an act of bioterrorism. However, the more widespread use of ClO2 gas to meet current and unforeseen decontamination needs has been hampered because the gas is too unstable for shipment and must be prepared at the application site. Newer technology allows for easy, onsite gas generation without the need for dedicated equipment, electricity, water, or personnel with advanced training. In a laboratory model system, 2 unique applications (personal protective equipment [PPE] and animal skin) were investigated in the context of potential development of decontamination protocols. Such protocols could serve to reduce human exposure to bacteria in a decontamination response effort. Chlorine dioxide gas was capable of reducing (2-7 logs of vegetative and spore-forming bacteria), and in some instances eliminating, culturable bacteria from difficult to clean areas on PPE facepieces. The gas was effective in eliminating naturally occurring bacteria on animal skin and also on skin inoculated with Bacillus spores. The culturable bacteria, including Bacillus spores, were eliminated in a time- and dose-dependent manner. Results of these studies suggested portable, easily used ClO2 gas generation systems have excellent potential for protocol development to contribute to biodefense strategies and decontamination responses to infectious disease outbreaks or other biothreat events.

  5. Seasonal and Topographic Variation in Net Primary Productivity and Water Use Efficiency in a Southwest Sky Island Fores

    Science.gov (United States)

    Murphy, P.; Minor, R. L.; Sanchez-Canete, E. P.; Potts, D. L.; Barron-Gafford, G.

    2016-12-01

    Western North American Forests represent an uncertain sink for atmospheric carbon. While understanding of the physical drivers of productivity in these forests has grown in the last decade, the relative influence of topographic position in the complex terrain of montane systems remains understudied. The high-latitude mixed conifer forest ecosystems of the southern Arizona Madrean Sky Islands are characterized by low precipitation, high annual variation in temperature, and heterogeneous topography. Eddy covariance measurements these forests show distinct seasonal trends due to temperature and bi-modal precipitation patterns, but these measurements are unable to resolve potential differences in physiological function on opposing north and south aspects within the footprint of the tower. Most of the year, north aspects receive less energy input due to the oblique angle of incoming solar radiation, leading to a divergence in soil moistures and temperatures. However, overall movement of energy and material is much higher on these north aspects on an annual basis. The implications of these differences for net primary productivity (NPP) and water use efficiency (WUE) are poorly addressed in the literature. We evaluated the relative control that topography has on the physical environment (soil moisture and temperature) and how these factors affect water stress, NPP, and WUE. We combined leaf-level measurements of photosynthesis and transpiration with other physiological and meteorological measurements to determine how the dominant vegetation functions as a result of microclimatic conditions. Initial results from the spring and summer measurement periods suggest topographical differences in microclimate, resulting in differences in NPP in the spring, but not the summer. Also, each of the three species on the same aspect responded differently to the same microclimatic conditions, underscoring interspecific variation at the site. How might these patterns change throughout an

  6. Relationships between net primary productivity and forest stand age derived from Forest Inventory and Analysis data and remote sensing imagery

    Science.gov (United States)

    He, L.; Chen, J. M.; Pan, Y.; Birdsey, R.

    2010-12-01

    Forest net primary productivity (NPP) varies greatly with stand age, and quantitative information on NPP-age relationship is therefore fundamentally important for forest carbon cycle modeling. We may use four terms to calculate NPP: annual accumulation of live biomass, annual mortality of aboveground and belowground biomass, foliage turnover to soil, and fine root turnover in soil. To derive NPP-age relationships for US forests, the Forest Inventory and Analysis (FIA) data are used to estimate the first two terms. The last two terms make up more than 50% of total NPP, but their estimates are highly uncertain based on limited available empirical relationships between aboveground biomass and foliage or fine root biomass. These estimates are mostly confounded by unknown variations of the turnover rates (TR) related to stand age because such field information is rare. To resolve this problem, we developed a new approach by using a leaf area index (LAI) map and a forest age map at 1 km resolution to derive LAI-age relationships for 18 major forest species groups in the USA. These relationships are then used to derive foliage TR using species-specific leaf longevity values. These relationships are also used for estimating the fine root TR based on reliable relationships between fine root and foliage TR. This combination of FIA and remote sensing data allows us for the first time to derive reliable NPP-age relationships for different forest types in USA (Figure 1). The derived relationships show a general temporal pattern of rapid increase in NPP in early ages, peak growth in mid-ages, and slow decline in old ages. The patterns are subjected to climate conditions, and can also be influenced by forest management. These relationships are further generalized for three major forest biomes for continental-scale carbon cycle modeling in conjunction with remotely sensed land cover types. The NPP relationships derived here may have many uses for analysis of management and climate

  7. Flue gas desulfurization by-products additions to acid soil: alfalfa productivity and environmental quality

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.; Dick, W.A.; Nelson, S.

    2001-07-01

    Flue gas desulfurization (FGD) by-products are often alkaline and contain many plant nutrients. Land application of FGD by-products is encouraged but little information is available related to plant responses and environmental impacts concerning such use. Agricultural lime (ag-lime) and several new types of FGD by-products which contain either vermiculite or perlite were applied at 0, 0.5, 1.0, and 2.0 times the soil's lime requirement (LR) rate to an acidic soil (Wooster silt loam). The highest FGD by-products application rate was equivalent to 75.2 Mg ha{sup -1}. Growth of alfalfa (Medicago sativa L.) was significantly increased compared to the untreated control in the second year after treatment with yields for the 1 x LR rate of FGD approximately 7-8 times greater compared to the untreated control and 30% greater than for the commercial ag-lime. Concentrations of Mo in alfalfa were significantly increased by FGD by-products application, compared to the untreated control, while compared to the ag-lime treatment, concentrations of B increased and Ba decreased. No soil contamination problems were observed, even at the 2xLR rate, indicating these materials can be safely applied to agricultural soils.

  8. RESTful NET

    CERN Document Server

    Flanders, Jon

    2008-01-01

    RESTful .NET is the first book that teaches Windows developers to build RESTful web services using the latest Microsoft tools. Written by Windows Communication Foundation (WFC) expert Jon Flanders, this hands-on tutorial demonstrates how you can use WCF and other components of the .NET 3.5 Framework to build, deploy and use REST-based web services in a variety of application scenarios. RESTful architecture offers a simpler approach to building web services than SOAP, SOA, and the cumbersome WS- stack. And WCF has proven to be a flexible technology for building distributed systems not necessa

  9. Assessing greenhouse gas emissions from Swedish Production : A study on the possibility to reduce the greenhouse gas emissions from the ten most valuable production categories in Sweden

    OpenAIRE

    Richter, Vide

    2015-01-01

    Industrialised and developing countries face an urgent challenge to decouple economic growth and greenhouse gas emissions. The aim of this study is to investigate where the largest potentials are to the Swedish industry decrease greenhouse gas emissions without increasing their costs. To limit the scope of the study is made by assessing the 10 largest categories of production by value sold in Sweden. The objectives are to investigate: (a) which the 10 largest categories are; (b) how much the ...

  10. Techno-economic assessment of membrane gas absorption for the production of carbon dioxide from flue gas

    NARCIS (Netherlands)

    Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Membrane gas absorption for carbon dioxide production from flue gases is discussed with special reference to the economics of the supply of carbon dioxide to greenhouses in the Netherlands. Novel absorption liquids have been introduced which show as excellent performance in terms of system stability

  11. Petri Nets

    Indian Academy of Sciences (India)

    Associate Professor of. Computer Science and. Automation at the Indian. Institute of Science,. Bangalore. His research interests are broadly in the areas of stochastic modeling and scheduling methodologies for future factories; and object oriented modeling. GENERAL I ARTICLE. Petri Nets. 1. Overview and Foundations.

  12. Petri Nets

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 8. Petri Nets - Overview and Foundations. Y Narahari. General Article Volume 4 Issue 8 August 1999 pp ... Author Affiliations. Y Narahari1. Department ot Computer Science and Automation, Indian Institute of Science, Bangalore 560 012, India.

  13. Gas exchange rates, plant height, yield components, and productivity of upland rice as affected by plant regulators

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Félix Alvarez

    2012-10-01

    Full Text Available The objective of this work was to evaluate gas exchange rates, plant height, yield components, and productivity of upland rice, as affected by type and application time of plant growth regulators. A randomized block design, in a 4x2 factorial arrangement, with four replicates was used. Treatments consisted of three growth regulators (mepiquat chloride, trinexapac-ethyl, and paclobutrazol, besides a control treatment applied at two different phenological stages: early tillering or panicle primordial differentiation. The experiment was performed under sprinkler-irrigated field conditions. Net CO2 assimilation, stomatal conductance, plant transpiration, and water-use efficiency were measured four times in Primavera upland rice cultivar, between booting and milky grain phenophases. Gas exchange rates were neither influenced by growth regulators nor by application time. There was, however, interaction between these factors on the other variables. Application of trinexapac-ethyl at both tillering and differentiation stages reduced plant height and negatively affected yield components and rice productivity. However, paclobutrazol and mepiquat chloride applied at tillering, reduced plant height without affecting rice yield. Mepiquat chloride acted as a growth stimulator when applied at the differentiation stage, and significantly increased plant height, panicle number, and grain yield of upland rice.

  14. Calculating net primary productivity of forest ecosystem with G4M model: case study on South Korea

    Science.gov (United States)

    Sung, S.; Forsell, N.; Kindermann, G.; Lee, D. K.

    2015-12-01

    Net primary productivity (NPP) is considered as an important indicator for forest ecosystem since the role of forest is highlighted as a stepping stone for mitigating climate change. Especially rapidly urbanizing countries which have high carbon dioxide emission have large interest in calculating forest NPP under climate change. Also maximizing carbon sequestration in forest sector has became a global goal to minimize the impacts of climate change. Therefore, the objective of this research is estimating carbon stock change under the different climate change scenarios by using G4M (Global Forestry Model) model in South Korea. We analyzed four climate change scenarios in different Representative Concentration Pathway (RCP). In this study we used higher resolution data (1kmx1km) to produce precise estimation on NPP from regionalized four climate change scenarios in G4M model. Finally, we set up other environmental variables for G4M such as water holding capacity, soil type and elevation. As a result of this study, temperature showed significant trend during 2011 to 2100. Average annual temperature increased more than 5℃ in RCP 8.5 scenario while 1℃ increased in RCP 2.6 scenario. Each standard deviation of the annual average temperature showed similar trend. Average annual precipitation showed similarity within four scenarios. However the standard deviation of average annual precipitation is higher in RCP8.5 scenario which indicates the ranges of precipitation is wider in RCP8.5 scenario. These results present that climate indicators such as temperature and precipitation have uncertainties in climate change scenarios. NPP has changed from 5-13tC/ha/year in RCP2.6 scenario to 9-21 tC/ha/year in RCP8.5 scenario in 2100. In addition the spatial distribution of NPP presented different trend among the scenarios. In conclusion we calculated differences in temperature and precipitation and NPP change in different climate change scenarios. This study can be applied for

  15. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    Science.gov (United States)

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

  16. European energy security: An analysis of future Russian natural gas production and exports

    Energy Technology Data Exchange (ETDEWEB)

    Soederbergh, Bengt, E-mail: bengt.soderbergh@fysast.uu.s [Global Energy Systems, Department of Physics and Astronomy, Uppsala University, Laegerhyddsvaegen 1, Box 535, SE-751 21, Uppsala (Sweden); Jakobsson, Kristofer; Aleklett, Kjell [Global Energy Systems, Department of Physics and Astronomy, Uppsala University, Laegerhyddsvaegen 1, Box 535, SE-751 21, Uppsala (Sweden)

    2010-12-15

    The widening gap between EU gas production and consumption may require an 87% increase of import volumes between 2006 and 2030, and there are great uncertainties regarding the amounts of gas that can be expected from new suppliers. The potential of increased production from Norway and Algeria is limited; hence, Russia is likely to play a crucial part of meeting the anticipated growing gas demand of the EU. A field-by-field study of 83 giant gas fields shows that the major producing Russian gas fields are in decline, and by 2013 much larger supplies from the Yamal Peninsula and the Shtokman field will be needed in order to avoid a decline in production. Gas from fields in Eastern Siberia and the Far East will mainly be directed to the Asian and Pacific Rim markets, thereby limiting its relevance to the European and CIS markets. As a result, the maximum export increase to the European and CIS markets amounts only to about 45% for the period 2015-2030. The discourse surrounding the EU's dependence on Russian gas should thus not only be concerned with geopolitics, but also with the issue of resource limitations. - Research highlights: {yields}Natural gas production in the Nadym Pur Taz region (Western Siberia) will start to decline within a few years. {yields}New production from the Yamal peninsula is critical to ensure gas exports to Europe. {yields}Additional production in East Siberia and the Far East will not be available for the European market. {yields}Rapid gas demand growth in China might also lead to competition for gas from Western Siberia.

  17. THE SHALE SOLUTION -How the Economic Growth Shale Gas Production in Pennsylvania has Contributed to can be Maintained, Even After the Gas is Depleted.

    OpenAIRE

    Akselsen, Anniken Berg

    2014-01-01

    The emergence of hydrocarbon energy extracted from shale has been nicknamed the Shale Gas Revolution , due to its implications for the American society, geo-politics and economy. This thesis will explain how the economic growth shale gas production in Pennsylvania so far has contributed to can be maintained, also for the future, when shale gas is no longer produced or depleted. By focusing on Pennsylvania, which has the nation s highest shale gas production growth rate, this thesis will exam...

  18. Dual Layer Monolith ATR of Pyrolysis Oil for Distributed Synthesis Gas Production

    Energy Technology Data Exchange (ETDEWEB)

    Lawal, Adeniyi [Stevens Institute of Technology, Castle Point Hoboken NJ 07030

    2012-09-29

    We have successfully demonstrated a novel reactor technology, based on BASF dual layer monolith catalyst, for miniaturizing the autothermal reforming of pyrolysis oil to syngas, the second and most critical of the three steps for thermochemically converting biomass waste to liquid transportation fuel. The technology was applied to aged as well as fresh samples of pyrolysis oil derived from five different biomass feedstocks, namely switch-grass, sawdust, hardwood/softwood, golden rod and maple. Optimization of process conditions in conjunction with innovative reactor system design enabled the minimization of carbon deposit and control of the H2/CO ratio of the product gas. A comprehensive techno-economic analysis of the integrated process using in part, experimental data from the project, indicates (1) net energy recovery of 49% accounting for all losses and external energy input, (2) weight of diesel oil produced as a percent of the biomass to be ~14%, and (3) for a demonstration size biomass to Fischer-Tropsch liquid plant of ~ 2000 daily barrels of diesel, the price of the diesel produced is ~$3.30 per gallon, ex. tax. However, the extension of catalyst life is critical to the realization of the projected economics. Catalyst deactivation was observed and the modes of deactivation, both reversible and irreversible were identified. An effective catalyst regeneration strategy was successfully demonstrated for reversible catalyst deactivation while a catalyst preservation strategy was proposed for preventing irreversible catalyst deactivation. Future work should therefore be focused on extending the catalyst life, and a successful demonstration of an extended (> 500 on-stream hours) catalyst life would affirm the commercial viability of the process.

  19. Net Surface Shortwave Radiation from GOES Imagery—Product Evaluation Using Ground-Based Measurements from SURFRAD

    Directory of Open Access Journals (Sweden)

    Anand K. Inamdar

    2015-08-01

    Full Text Available The Earth’s surface net radiation controls the energy and water exchanges between the Earth’s surface and the atmosphere, and can be derived from satellite observations. The ability to monitor the net surface radiation over large areas at high spatial and temporal resolution is essential for many applications, such as weather forecasting, short-term climate prediction or water resources management. The objective of this paper is to derive the net surface radiation in the shortwave domain at high temporal (half-hourly and spatial resolution (~1 km using visible imagery from Geostationary Operational Environmental Satellite (GOES. The retrieval algorithm represents an adaptation to GOES data of a standard algorithm initially developed for the NASA-operated Clouds and Earth’s Radiant Energy System (CERES scanner. The methodology relies on: (1 the estimation of top of atmosphere shortwave radiation from GOES spectral measurements; and (2 the calculation of net surface shortwave (SW radiation accounting for atmospheric effects. Comparison of GOES-retrieved net surface shortwave radiation with ground-measurements at the National Oceanic and Atmospheric Administration’s (NOAA Surface Radiation (SURFRAD stations yields very good agreement with average bias lower than 5 W·m−2 and root mean square difference around 70 W·m−2. The algorithm performance is usually higher over areas characterized by low spatial variability in term of land cover type and surface biophysical properties. The technique does not involve retrieval and assessment of cloud properties and can be easily adapted to other meteorological satellites around the globe.

  20. Hydrogen Gas Production in a Stand-Alone Wind Farm

    Directory of Open Access Journals (Sweden)

    M. Naziry Kordkandy

    2017-04-01

    Full Text Available This paper is analyzing the operation of a stand-alone wind farm with variable speed turbines, permanent magnet synchronous generators (PMSG and a system for converting wind energy during wind speed variations. On this paper, the design and modeling of a wind system which uses PMSG’s to provide the required power of a hydrogen gas electrolyzer system, is discussed. This wind farm consists of three wind turbines, boost DC-DC converters, diode full bridge rectifiers, permanent magnet synchronous generators, MPPT control and a hydrogen gas electrolyzer system. The MPPT controller based on fuzzy logic is designed to adjust the duty ratio of the boost DC-DC converters to absorb maximum power. The proposed fuzzy logic controller assimilates, with (PSF MPPT algorithm which generally used to absorb maximum power from paralleled wind turbines and stores it in form of hydrogen gas. The system is modeled and its behavior is studied using the MATLAB software.

  1. Process for production of synthesis gas with reduced sulfur content

    Science.gov (United States)

    Najjar, Mitri S.; Corbeels, Roger J.; Kokturk, Uygur

    1989-01-01

    A process for the partial oxidation of a sulfur- and silicate-containing carbonaceous fuel to produce a synthesis gas with reduced sulfur content which comprises partially oxidizing said fuel at a temperature in the range of 1800.degree.-2200.degree. F. in the presence of a temperature moderator, an oxygen-containing gas and a sulfur capture additive which comprises an iron-containing compound portion and a sodium-containing compound portion to produce a synthesis gas comprising H.sub.2 and CO with a reduced sulfur content and a molten slag which comprises (i) a sulfur-containing sodium-iron silicate phase and (ii) a sodium-iron sulfide phase. The sulfur capture additive may optionally comprise a copper-containing compound portion.

  2. Production Decline Analysis for Two-Phase Flow in Multifractured Horizontal Well in Shale Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Wei-Yang Xie

    2015-01-01

    Full Text Available After multistage fracturing, the flowback of fracturing fluid will cause two-phase flow through hydraulic fractures in shale gas reservoirs. With the consideration of two-phase flow and desorbed gas transient diffusion in shale gas reservoirs, a two-phase transient flow model of multistage fractured horizontal well in shale gas reservoirs was created. Accurate solution to this flow model is obtained by the use of source function theory, Laplace transform, three-dimensional eigenvalue method, and orthogonal transformation. According to the model’s solution, the bilogarithmic type curves of the two-phase model are illustrated, and the production decline performance under the effects of hydraulic fractures and shale gas reservoir properties are discussed. The result obtained in this paper has important significance to understand pressure response characteristics and production decline law of two-phase flow in shale gas reservoirs. Moreover, it provides the theoretical basis for exploiting this reservoir efficiently.

  3. THE DEVELOPMENT OF OIL AND GAS PRODUCTION GATHERING AND TRANSPORTATION TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Mirko Zelić

    1990-12-01

    Full Text Available The oil production was started in 1945 to cover several small capacity oil fields and to expand in the forthcoming forty-five years to the wider area of the Northern Croatia. Significant exploration efforts and enthusiasm revealed perspective hydrocarbon layers on which a complex technological infrastructure was constructed (wells, technological systems, transportation systems for the purpose of oil and gas production, its processing and transportation to refineries and consumers. In line with development of other technoligies in the world, the oil and gas production and gathering technologies in INA - Naftaplin were also up—graded, monitoring and adopting the most advanced world achievements in the field of oil and gas production. Presently applied technology ranks INA - Naftaplin among modernly organized (from the technical and technologica point of view companies, engaged in the field of oil and gas production and processing (the paper is published in Croatian.

  4. Production of "Green Natural Gas" Using Solid Oxide Electrolysis Cells (SOEC): Status of Technology and Costs

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Jensen, Søren Højgaard; Ebbesen, Sune Dalgaard

    2012-01-01

    This paper gives arguments in favour of using green natural gas (GNG) as storage media for the intermittent renewable energy sources. GNG is here defined as being CH4, i.e. methane, often called synthetic natural gas or substitute natural gas (SNG), produced using renewable or at least CO2 neutral...... energy sources only. Also dimethyl ether (DME = (CH3)2O), which might be called Liquefied Green Gas, LGG, in analogy to Liquefied Petroleum Gas, LPG, because DME has properties similar to LPG. It further gives a short review of the state of the art of electrolysis in general and SOEC in particular....... Production of synthesis gas (H2 + CO) from CO2 and H2O using SOEC technology is evaluated. GNG and LGG can be produced from synthesis gas (or short: syngas) by means of well established commercially available catalysis technology. Finally, estimations of costs and efficiencies are presented and the relative...

  5. Effect of different crop management systems on net primary productivity and relative carbon allocation coefficients for corn (Zea mays L.

    Directory of Open Access Journals (Sweden)

    S. Khorramdel

    2016-04-01

    Full Text Available In order to evaluate the effect of different crop management practices on corn (Zea mays L. net primary productivity (NPP and relative carbon allocation coefficients, a field experiment was conducted based on a completely randomized block design with four replications in the Agricultural Research Station, Ferdowsi University of Mashhad, Iran during two growing season 2008-2009 and 2009-2010. Treatments including two low input management systems based on application of cow manure and compost municipal made from house-hold waste, a medium input system and a high input system. Application of inputs and management practices were based on a basic assumption made prior to the start of the experiment. On the other words, for each of the management system the particular set of inputs were allocated. In this respect, for low input system 30 t.ha-1 cow manure or 30 t.ha-1 compost municipal made from house-hold waste, twice hand weeding were used. In medium management system, 15 t.ha-1 compost municipal made from house-hold waste, 150 kg.ha-1 urea, two seed bed operations, 1.5 l.ha-1 2, 4-D herbicide applied at five-leaf stage and one time hand weeding were used. In high input system, the inputs were two seed bed operations, 2 l.ha-1 Paraquat herbicide used after seeding and 1.5 l.ha-1 2, 4-D applied at five-leaf stage. Results showed that the effect of different crop management practices on the shoot biomass, seed weight, root biomass, total biomass, shoot biomass: root biomass (S:R, SRL and HI were significant (p≥0.01. High input management system enhanced total biomass and S:R and decreased seed weight, root biomass and SRL. The highest and the lowest total biomass observed in high input (18.3 kg.m-2.yr-1 and low input with using compost (10.3 kg.m-2.yr-1, respectively. The maximum SRL observed in low input based on cow manure application (19.8 cm.cm-3 soil and the minimum SRL was in high input (1.3 cm.cm-3 soil. Range of relative carbon allocation

  6. Potential of Ruminant Feed with Appearance of In Vitro Gas Production

    Directory of Open Access Journals (Sweden)

    Firsoni

    2017-10-01

    Full Text Available Indonesia has many kinds of feedstuff with different qualities that can be used as ruminants feed. One way to evaluate it is analyzing the performance of the feed gas production value in vitro. Feed ingredients tested in this study were the flour of coffee hull, peanut hull, field grass, turn leaves, rice straw and fermented rice straw. Samples weighed 200 ± 5 mg, put into a 100 ml syringe glass, added 30 ml buffalo rumen liquor with bicarbonate buffer medium, then incubated in the water bath at 39 ° C for 48 hours. Neway software and random block design with 4 blocks are used to calculate the value of fitted gas and to analyze the variance. The variables measured were gas production 2, 4, 6, 8, 10, 12, 24, 48, 72 and 96 hours, organic material degradable, gas production potential (a+b, gas production rate (k. The highest gas production 24, 48 and 72 hours from the field grass treatment (C was 36.33, 51.12 and 56.29 ml/200 mg DM but 96 hours of rice straw ie 59.60 ml/200 mg DM, while the lowest (24, 48, 72 and 96 hours of coffee skin (6.08, 7.77, 7.61, and 7.68 ml/200 mg DM respectively. The highest gas production potential of rice straw is 69.13 ml/200 mg DM and the lowest of coffee skin is 7.72 ml/200 mg BK. The highest percentage of gas production after 24 hours was obtained Turi leaves (D: 91.46% and the lowest rice straw (E: 41.22%. Rice straw can be suggested to be field grass substitution by processed again to reduce its crude fiber content, while the coffee and peanut hulls need further study, due to low gas production potential of 7.72 and 11.45 ml / 200 mg DM.

  7. Prediction of Gas Leak Tightness of Superplastically Formed Products

    NARCIS (Netherlands)

    Snippe, Q.H.C.; Meinders, Vincent T.; Barlat, F; Moon, Y.H.; Lee, M.G.

    2010-01-01

    In some applications, in this case an aluminium box in a subatomic particle detector containing highly sensitive detecting devices, it is important that a formed sheet should show no gas leak from one side to the other. In order to prevent a trial-and-error procedure to make this leak tight box, a

  8. Production of Renewable Natural Gas from Waste Biomass

    Science.gov (United States)

    Kumar, Sachin; Suresh, S.; Arisutha, S.

    2013-03-01

    Biomass energy is expected to make a major contribution to the replacement of fossil fuels. Methane produced from biomass is referred to as bio-methane, green gas, bio-substitute natural gas or renewable natural gas (RNG) when it is used as a transport fuel. Research on upgrading of the cleaned producer gas to RNG is still ongoing. The present study deals with the conversion of woody biomass into fuels, RNG using gasifier. The various effects of parameters like temperature, pressure, and tar formation on conversion were also studied. The complete carbon conversion was observed at 480 °C and tar yield was significantly less. When biomass was gasified with and without catalyst at about 28 s residence time, ~75 % (w/w) and 88 % (w/w) carbon conversion for without and with catalyst was observed. The interest in RNG is growing; several initiatives to demonstrate the thermal-chemical conversion of biomass into methane and/or RNG are under development.

  9. 593 NUTRIENT VALUE AND IN VITRO GAS PRODUCTION OF ...

    African Journals Online (AJOL)

    ABSTRACT. Cost of feeding conventional feedstuffs to ruminants in Nigeria is prohibitive. African wild cocoyam (Colocasia esculentum) is an unconventional energy feed source and non human edible food. The study determined the chemical composition and energy content, secondary metabolites and in vitro gas ...

  10. Problem of Production of Shale Gas in Germany

    Directory of Open Access Journals (Sweden)

    Nataliya K. Meden

    2014-01-01

    Full Text Available A bstract: Our magazine publishes a series of articles on shale gas in different countries. This article is about Germany, a main importer of Russian natural gas, so a perspective of exploitation of local shale gas resources is of a clear practical importance for Russia. We discuss external and internal factors which determine position of the German government concerning the shale gas excavation: policy of the USA and the EU, positions of German political parties, influence of the lobbying communities and civic associations. The article contains rich information on vast variety of interests of actors in the domestic discussion. Taking into account the importance of civil society for political decisions, the author rests upon public relations of big companies, their methodic and results. The article summarizes data on reserve estimation and current geological projects, as well all the officially published reports concerning environmental threats cased by fracking technology. On the base of the above analyze, the author predicts possible evolution of the federal government policy.

  11. Microbiology of synthesis gas fermentation for biofuel production

    NARCIS (Netherlands)

    Henstra, A.M.; Sipma, J.; Rinzema, A.; Stams, A.J.M.

    2007-01-01

    A significant portion of biomass sources like straw and wood is poorly degradable and cannot be converted to biofuels by microorganisms. The gasification of this waste material to produce synthesis gas (or syngas) could offer a solution to this problem, as microorganisms that convert CO and H2 (the

  12. Maximization of natural gas liquids production from an

    Directory of Open Access Journals (Sweden)

    Ahmed Abd El-Kader Bhran

    2016-09-01

    Full Text Available It is known that the price of liquefied petroleum gas (LPG is higher than that of natural gas from which it is derived. So the modification of a natural gas plant to produce LPG instead of lighter hydrocarbon gases is very important in the view point of economics. The aim of the present work is directed to the modification of Salam gas plant (Khalda Petroleum Company-Egypt to produce LPG from the NGL instead of producing hydrocarbon gases during the NGL stabilization. This can be achieved after adding de-ethanizer and de-butanizer towers. The simulation tool used in this study is HYSYS version 8.4. The produced LPG of 100 ton/day can participate to solve the LPG shortage problem in Egypt and provide a national service to the people of Matruh Governorate. The economic study based on the economic analyzer of HYSIS showed that the pay-back period of the added two towers and their additional equipment has a high investment strength which means that all modification costs will be recovered within a short time. Furthermore, there are other benefits from this modification. The simulation results showed that there is a capacity saving of 56 tons/day in the export pipeline which transfers the gases to western desert gas complex (WDGC at Alexandria. In the same manner, the modified plant provides a capacity saving of 88 tons/day in the dehydration unit and reduces horse power consumption in recycle and first stage export compressors. This modification can be taken as guidelines for both new and plants in operation to increase their profits.

  13. WegenerNet climate station network region Feldbach/Austria: From local measurements to weather and climate data products at 1 km-scale resolution

    Science.gov (United States)

    Kabas, T.; Leuprecht, A.; Bichler, C.; Kirchengast, G.

    2010-12-01

    South-eastern Austria is characteristic for experiencing a rich variety of weather and climate patterns. For this reason, the county of Feldbach was selected by the Wegener Center as a focus area for a pioneering observation experiment at very high resolution: The WegenerNet climate station network (in brief WegenerNet) comprises 151 meteorological stations within an area of about 20 km × 15 km (~ 1.4 km × 1.4 km station grid). All stations measure the main parameters temperature, humidity and precipitation with 5 minute sampling. Selected further stations include measurements of wind speed and direction completed by soil parameters as well as air pressure and net radiation. The collected data is integrated in an automatic processing system including data transfer, quality control, product generation, and visualization. Each station is equipped with an internet-attached data logger and the measurements are transferred as binary files via GPRS to the WegenerNet server in 1 hour intervals. The incoming raw data files of measured parameters as well as several operating values of the data logger are stored in a relational database (PostgreSQL). Next, the raw data pass the Quality Control System (QCS) in which the data are checked for its technical and physical plausibility (e.g., sensor specifications, temporal and spatial variability). In consideration of the data quality (quality flag), the Data Product Generator (DPG) results in weather and climate data products on various temporal scales (from 5 min to annual) for single stations and regular grids. Gridded data are derived by vertical scaling and squared inverse distance interpolation (1 km × 1 km and 0.01° × 0.01° grids). Both subsystems (QCS and DPG) are realized by the programming language Python. For application purposes the resulting data products are available via the bi-lingual (dt, en) WegenerNet data portal (www.wegenernet.org). At this time, the main interface is still online in a system in which

  14. Real-Time Optimization of a maturing North Sea gas asset with production constraints

    NARCIS (Netherlands)

    Linden, R.J.P. van der; Busking, T.E.

    2013-01-01

    As gas and oil fields mature their operation becomes increasingly more complex, due to complex process dynamics, like slugging, gas coning, water breakthrough, salt or hydrate deposition. Moreover these phenomena also lead to production constraints in the upstream facilities. This complexity asks

  15. Eco-efficient environmental policy in oil and gas production in The Netherlands

    NARCIS (Netherlands)

    Huppes, G.; Davidson, M.D.; Kuyper, J.; van Oers, L.; Udo de Haes, H.A.; Warringa, G.

    2007-01-01

    This article presents the quantitative eco-efficiency method developed for prioritising environmental investments in NOGEPA, The Netherlands Oil and Gas Exploration and Production Association involving all major oil and gas producers in The Netherlands. They are committed to a high level of

  16. A preliminary analysis of floating production storage and offloading facilities with gas liquefaction processes

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; Carranza-Sánchez, Yamid Alberto; Junior, Silvio de Oliveira

    2016-01-01

    Floating, production, storage and offloading (FPSO) plants are facilities used in upstream petroleum processing. They have gained interest because they are more flexible than conventional plants and can be used for producing oil and gas in deep-water fields. In general, gas export is challenging ...

  17. Methods for upgrading of a fuel gas and succinic acid production

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention provides methods of upgrading of a CO2-containing fuel gas comprising the use of anaerobic succinic acid-producing microorganisms. Thus, the present invention provides a method for simultaneous upgrading of a CO2-containing fuel gas and biosuccinic acid production....

  18. Gas production from a cold, stratigraphically-bounded gas hydrate deposit at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Implications of uncertainties

    Science.gov (United States)

    Moridis, G.J.; Silpngarmlert, S.; Reagan, M.T.; Collett, T.; Zhang, K.

    2011-01-01

    As part of an effort to identify suitable targets for a planned long-term field test, we investigate by means of numerical simulation the gas production potential from unit D, a stratigraphically bounded (Class 3) permafrost-associated hydrate occurrence penetrated in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well on North Slope, Alaska. This shallow, low-pressure deposit has high porosities (?? = 0.4), high intrinsic permeabilities (k = 10-12 m2) and high hydrate saturations (SH = 0.65). It has a low temperature (T = 2.3-2.6 ??C) because of its proximity to the overlying permafrost. The simulation results indicate that vertical wells operating at a constant bottomhole pressure would produce at very low rates for a very long period. Horizontal wells increase gas production by almost two orders of magnitude, but production remains low. Sensitivity analysis indicates that the initial deposit temperature is by the far the most important factor determining production performance (and the most effective criterion for target selection) because it controls the sensible heat available to fuel dissociation. Thus, a 1 ??C increase in temperature is sufficient to increase the production rate by a factor of almost 8. Production also increases with a decreasing hydrate saturation (because of a larger effective permeability for a given k), and is favored (to a lesser extent) by anisotropy. ?? 2010.

  19. County-level Oil and Gas Production in the U.S.

    Data.gov (United States)

    Department of Agriculture — County-level data from oil and/or natural gas producing States—for onshore production in the lower 48 States only—are compiled on a State-by-State basis. Most States...

  20. In vitro gas production of wheat grain flour coated with different fat ...

    African Journals Online (AJOL)

    Jane

    2011-07-27

    Jul 27, 2011 ... produce more glucose for high producing animals like dairy cows. Key words: .... neutral detergent fiber (NDF) were determined, as described by ..... rumen fermentation and gas production: influence of yellow grease, tallow ...

  1. [Effects of lead stress on net photosynthetic rate, SPAD value and ginsenoside production in Ginseng (Panax ginseng)].

    Science.gov (United States)

    Liang, Yao; Jiang, Xiao-Li; Yang, Fen-Tuan; Cao, Qing-Jun; Li, Gang

    2014-08-01

    The paper aimed to evaluate the effects of lead stress on photosynthetic performance and ginsenoside content in ginseng (Panax ginseng). To accomplish this, three years old ginseng were cultivated in pot and in phytotron with different concentrations of lead, ranging from 0 to 1000 mg x kg(-1) soil for a whole growth period (about 150 days). The photosynthetic parameters in leaves and ginsenoside content in roots of ginseng were determined in green fruit stage and before withering stage, respectively. In comparison with the control, net photosynthetic rate and SPAD value in ginseng leaves cultivated with 100 and 250 mg x kg(-1) of lead changed insignificantly, however, ginseng supplied with 500 and 1 000 mg x kg(-1) of lead showed a noticeably decline in the net rate of photosynthesis and SPAD value (P lead, with decline of 57.8%,11.0%, respectively. Total content of ginsenoside in ginseng roots cultivated with 100 mg x kg(-1) of lead showed insignificantly change compared to the control, but the content increased remarkably in treatments supplied with 250, 500, 1 000 mg x kg(-1) of lead (P lead. The net photosynthetic rate and SPAD value in leaves of ginseng both showed significantly negative linear correlations with lead stress level (P lead concentration was also observed (P lead negatively affects photosynthetic performance in ginseng leaves, but benefits for accumulation of secondary metabolism (total content of ginsenoside) in ginseng root.

  2. Methanol production with elemental phosphorus byproduct gas: technical and economic feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Lyke, S.E.; Moore, R.H.

    1981-01-01

    The technical and economic feasibility of using a typical, elemental, phosphorus byproduct gas stream in methanol production is assessed. The purpose of the study is to explore the potential of a substitute for natural gas. The first part of the study establishes economic tradeoffs between several alternative methods of supplying the hydrogen which is needed in the methanol synthesis process to react with CO from the off gas. The preferred alternative is the Battelle Process, which uses natural gas in combination with the off gas in an economically sized methanol plant. The second part of the study presents a preliminary basic design of a plant to (1) clean and compress the off gas, (2) return recovered phosphorus to the phosphorus plant, and (3) produce methanol by the Battelle Process. Use of elemental phosphorus byproduct gas in methanol production appears to be technically feasible. The Battelle Process shows a definite but relatively small economic advantage over conventional methanol manufacture based on natural gas alone. The process would be economically feasible only where natural gas supply and methanol market conditions at a phosphorus plant are not significantly less favorable than at competing methanol plants. If off-gas streams from two or more phosphorus plants could be combined, production of methanol using only offgas might also be economically feasible. The North American methanol market, however, does not seem likely to require another new methanol project until after 1990. The off-gas cleanup, compression, and phosphorus-recovery system could be used to produce a CO-rich stream that could be economically attractive for production of several other chemicals besides methanol.

  3. National Assessment of Oil and Gas Project: Areas of Historical Oil and Gas Exploration and Production in the United States

    Science.gov (United States)

    Biewick, Laura

    2008-01-01

    This report contains maps and associated spatial data showing historical oil and gas exploration and production in the United States. Because of the proprietary nature of many oil and gas well databases, the United States was divided into cells one-quarter square mile and the production status of all wells in a given cell was aggregated. Base-map reference data are included, using the U.S. Geological Survey (USGS) National Map, the USGS and American Geological Institute (AGI) Global GIS, and a World Shaded Relief map service from the ESRI Geography Network. A hardcopy map was created to synthesize recorded exploration data from 1859, when the first oil well was drilled in the U.S., to 2005. In addition to the hardcopy map product, the data have been refined and made more accessible through the use of Geographic Information System (GIS) tools. The cell data are included in a GIS database constructed for spatial analysis via the USGS Internet Map Service or by importing the data into GIS software such as ArcGIS. The USGS internet map service provides a number of useful and sophisticated geoprocessing and cartographic functions via an internet browser. Also included is a video clip of U.S. oil and gas exploration and production through time.

  4. Learning control for riser-slug elimination and production-rate optimization for an offshore oil and gas production process

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2014-01-01

    Slugging flow in the offshore oil & gas production attracts lot of attention due to it's limitation of production rate, periodic overload on processing facilities, and even direct cause of emergency shutdown. This work aims at two correlated objectives: (i) Preventing slugging flow; and meanwhile...

  5. EFFECTS OF OIL AND NATURAL GAS PRICES ON INDUSTRIAL PRODUCTION IN THE EUROZONE MEMBER COUNTRIES

    Directory of Open Access Journals (Sweden)

    Yılmaz BAYAR

    2014-04-01

    Full Text Available Industrial production is one of the leading indicators of gross domestic product which reflects the overall economic performance of a country. In other words decreases or increases in industrial production point out a contracting or expanding economy. Therefore, changes in prices of oil and natural gas which are the crucial inputs to the industrial production are also important for the overall economy. This study examines the effects of changes in oil and natural gas prices on the industrial production in the 18 Eurozone member countries during the period January 2001-September 2013 by using panel regression. We found that oil prices and natural gas prices had negative effect on industrial production in the Eurozone member countries.

  6. Nano- porous proppants for shale oil and gas production

    OpenAIRE

    Ottestad, Eirik

    2014-01-01

    Over the last decade a rapid increase in utilization of unconventional reservoirs ha occurred due to advances in horizontal drilling and multi-stage fracturing technology. Reservoirs that earlier were far beyond commercial reach are today producing oil and gas in competitive manner. The share of energy provided form unconventional reservoirs is projected to keep growing relative to conventional energy sources in the years to come. Proppants are essential component in hydraulic fracturing oper...

  7. Coupling Hydraulic Fracturing Propagation and Gas Well Performance for Simulation of Production in Unconventional Shale Gas Reservoirs

    Science.gov (United States)

    Wang, C.; Winterfeld, P. H.; Wu, Y. S.; Wang, Y.; Chen, D.; Yin, C.; Pan, Z.

    2014-12-01

    Hydraulic fracturing combined with horizontal drilling has made it possible to economically produce natural gas from unconventional shale gas reservoirs. An efficient methodology for evaluating hydraulic fracturing operation parameters, such as fluid and proppant properties, injection rates, and wellhead pressure, is essential for the evaluation and efficient design of these processes. Traditional numerical evaluation and optimization approaches are usually based on simulated fracture properties such as the fracture area. In our opinion, a methodology based on simulated production data is better, because production is the goal of hydraulic fracturing and we can calibrate this approach with production data that is already known. This numerical methodology requires a fully-coupled hydraulic fracture propagation and multi-phase flow model. In this paper, we present a general fully-coupled numerical framework to simulate hydraulic fracturing and post-fracture gas well performance. This three-dimensional, multi-phase simulator focuses on: (1) fracture width increase and fracture propagation that occurs as slurry is injected into the fracture, (2) erosion caused by fracture fluids and leakoff, (3) proppant subsidence and flowback, and (4) multi-phase fluid flow through various-scaled anisotropic natural and man-made fractures. Mathematical and numerical details on how to fully couple the fracture propagation and fluid flow parts are discussed. Hydraulic fracturing and production operation parameters, and properties of the reservoir, fluids, and proppants, are taken into account. The well may be horizontal, vertical, or deviated, as well as open-hole or cemented. The simulator is verified based on benchmarks from the literature and we show its application by simulating fracture network (hydraulic and natural fractures) propagation and production data history matching of a field in China. We also conduct a series of real-data modeling studies with different combinations of

  8. La plataforma .NET

    OpenAIRE

    Fornas Estrada, Miquel

    2008-01-01

    L'aparició de la plataforma .NET Framework ha suposat un canvi molt important en la forma de crear i distribuir aplicacions, degut a que incorpora una sèrie d'innovacions tècniques i productives que simplifiquen molt les tasques necessàries per desenvolupar un projecte. La aparición de la plataforma. NET Framework ha supuesto un cambio muy importante en la forma de crear y distribuir aplicaciones, debido a que incorpora una serie de innovaciones técnicas y productivas que simplifican mucho...

  9. THE ADVANTAGES AND DISADVANTAGES OF THE PRODUCTION OF SHALE GAS POTENTIAL : THE CASE OF TURKEY

    Directory of Open Access Journals (Sweden)

    TURGUT BAYRAMOĞLU

    2015-12-01

    Full Text Available Energy is a main input for economy. Because of an increase in other fossil fuels’ prices and it’s accepted as an important resource for energy supply for the countries which don’t have enough oil and natural gas resources, shale gas became a current issue in the world. Technically producable shale gas in the world is about 6.621 bcm (billion cubic meter. We can say that this amount may be higher if unsought areas are added. Turkey is one of the countries which has shale gas potential. According to a report published by EIA in 2011, Turkey has approximately 424 billion cubic meter shale gas reserves. This shale gas potential can reduce Turkey’s energy dependence if we think of the fact that annual natural gas consumption of Turkey is 46 bcm. Despite all, production of shale gas has not been searched in terms of it’s advantages and disadvantages. The aim of this study is to present the advantages and disadvantages of shales gas for the world and Turkey. Reducing energy dependence, supporting a more clean energy than coal, balancing the oil prices are some advantages. Nevertheless, it’s a fossil fuel, it’s production is expensive and it gets negative social and environmental reactions.

  10. Numerical studies of depressurization-induced gas production from an interbedded marine turbidite gas hydrate reservoir model

    Science.gov (United States)

    Myshakin, Evgeniy; Lin, Jeen-Shang; Uchida, Shun; Seol, Yongkoo; Collett, Timothy S.; Boswell, Ray

    2017-01-01

    The numerical simulation of thin hydrate-bearing sand layers interbedded with mud layers is investigated. In this model, the lowest hydrate layer occurs at the base of gas hydrate stability and overlies a thinly-interbedded saline aquifer. The predicted gas rates reach 6.25 MMscf/day (1.77 x 105 m3 /day) after 90 days of continuous depressurization with manageable water production. Development of horizontal dissociating interfaces between hydrate-bearing sand and mud layers is a primary determinant of reservoir performance. A set of simulations has been executed to assess uncertainty in in situ permeability and to determine the impact of the saline aquifer on productivity.

  11. On-site methanol production plant from natural gas with modular HTR

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Eiji; Ohashi, Kazutaka; Hayakawa, Hitoshi [Fuji Electric Co. Ltd., Kawasaki, Kanagawa (Japan)

    1997-11-01

    The consumption of natural gas has been increasing year by year due to its relatively low level of CO{sub 2} emissions and low cost. All of the natural gas consumed in Japan is imported from foreign countries in the form of liquid natural gas (LNG). Therefore, liquefaction, transportation and storage equipment costs are large. On the other hand, handling methanol is as easy as handling oil. If a plant for producing methanol from natural gas is sited near a natural gas field, transportation and storage costs are expected to be significantly lower than such costs for LNG production. From the above viewpoint, the concept of an on-site methanol production plant with a modular HTR (High Temperature Reactor) was studied. (author)

  12. An integrated approach for gas dispersion, gas explosion and structural impact analysis for an offshore production platform on the Dutch continental shelf

    NARCIS (Netherlands)

    Korndörffer, W.; Schaap, D.; Heijden, A.M.A. van der; Versloot, N.H.A.

    2004-01-01

    The design of an offshore gas production platform has been subjected to an extensive quantitative risk analysis in particular with regard to its resistance to gas explosions loads. It was demonstrated that integration of the physical and structural effects of a gas explosion in an early stage of the

  13. Atmospheric hydrocarbon emissions and concentrations in the barnett shale natural gas production region.

    Science.gov (United States)

    Zavala-Araiza, Daniel; Sullivan, David W; Allen, David T

    2014-05-06

    Hourly ambient hydrocarbon concentration data were collected, in the Barnett Shale Natural Gas Production Region, using automated gas chromatography (auto-GC), for the period from April 2010 to December 2011. Data for three sites were compared: a site in the geographical center of the natural gas production region (Eagle Mountain Lake (EML)); a rural/suburban site at the periphery of the production region (Flower Mound Shiloh), and an urban site (Hinton). The dominant hydrocarbon species observed in the Barnett Shale region were light alkanes. Analyses of daily, monthly, and hourly patterns showed little variation in relative composition. Observed concentrations were compared to concentrations predicted using a dispersion model (AERMOD) and a spatially resolved inventory of volatile organic compounds (VOC) emissions from natural gas production (Barnett Shale Special Emissions Inventory) prepared by the Texas Commission on Environmental Quality (TCEQ), and other emissions information. The predicted concentrations of VOC due to natural gas production were 0-40% lower than background corrected measurements, after accounting for potential under-estimation of certain emission categories. Hourly and daily variations in observed, background corrected concentrations were primarily explained by variability in meteorology, suggesting that episodic emission events had little impact on hourly averaged concentrations. Total emissions for VOC from natural gas production sources are estimated to be approximately 25,300 tons/yr, when accounting for potential under-estimation of certain emission categories. This region produced, in 2011, approximately 5 bcf/d of natural gas (100 Gg/d) for a VOC to natural gas production ratio (mass basis) of 0.0006.

  14. International Clean Energy System Using Hydrogen Conversion (WE-NET). subtask 4. Development of hydrogen production technology; Suiso riyo kokusai clean energy system gijutsu (WE-NET). subtask 4. Suiso seizo gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This paper describes development of hydrogen production technology as a part of the WE-NET project. For the solid polymer water electrolysis method higher in efficiency and lower in cost than the previous methods, 5 companies have developed element technologies for improving electrolysis cells and synthesis technologies of hot solid polymer electrolyte based on each proper catalyst electrode production method. In fiscal 1996, the initial study on large-scale systems by middle laboratory cells was made as well as improvement of electrolysis performance by small laboratory cells and endurance tests. Among the previous methods such as a hot press method (bonding of an ion exchange membrane to an electrode), an electroless plating method (preparation of porous surface onto a membrane electrode assembly), a zero gap method (preparation of high-efficiency high-current density cells), and a sintered porous electrode method (carrying of the mixture of catalytic powder and ion exchange resin-dissipated solution onto sintered metallic porous electrode surface), the former two methods were adopted for development of bench-scale cells as effective promising methods. 192 refs., 183 figs., 108 tabs.

  15. Variability of oil and gas well productivities for continuous (unconventional) petroleum accumulations

    Science.gov (United States)

    Charpentier, Ronald R.; Cook, Troy A.

    2013-01-01

    Over the last decade, oil and gas well productivities were estimated using decline-curve analysis for thousands of wells as part of U.S. Geological Survey (USGS) studies of continuous (unconventional) oil and gas resources in the United States. The estimated ultimate recoveries (EURs) of these wells show great variability that was analyzed at three scales: within an assessment unit (AU), among AUs of similar reservoir type, and among groups of AUs with different reservoir types. Within a particular oil or gas AU (such as the Barnett Shale), EURs vary by about two orders of magnitude between the most productive wells and the least productive ones (excluding those that are dry and abandoned). The distributions of EURs are highly skewed, with most of the wells in the lower part of the range. Continuous AUs were divided into four categories based on reservoir type and major commodity (oil or gas): coalbed gas, shale gas, other low-permeability gas AUs (such as tight sands), and low-permeability oil AUs. Within each of these categories, there is great variability from AU to AU, as shown by plots of multiple EUR distributions. Comparing the means of each distribution within a category shows that the means themselves have a skewed distribution, with a range of approximately one to two orders of magnitude. A comparison of the three gas categories (coalbed gas, shale gas, and other low-permeability gas AUs) shows large overlap in the ranges of EUR distributions. Generally, coalbed gas AUs have lower EUR distributions, shale gas AUs have intermediate sizes, and the other low-permeability gas AUs have higher EUR distributions. The plot of EUR distributions for each category shows the range of variation among developed AUs in an appropriate context for viewing the historical development within a particular AU. The Barnett Shale is used as an example to demonstrate that dividing wells into groups by time allows one to see the changes in EUR distribution. Subdivision into groups

  16. Volatile organic compound emissions from unconventional natural gas production: Source signatures and air quality impacts

    Science.gov (United States)

    Swarthout, Robert F.

    Advances in horizontal drilling and hydraulic fracturing over the past two decades have allowed access to previously unrecoverable reservoirs of natural gas and led to an increase in natural gas production. Intensive unconventional natural gas extraction has led to concerns about impacts on air quality. Unconventional natural gas production has the potential to emit vast quantities of volatile organic compounds (VOCs) into the atmosphere. Many VOCs can be toxic, can produce ground-level ozone or secondary organic aerosols, and can impact climate. This dissertation presents the results of experiments designed to validate VOC measurement techniques, to quantify VOC emission rates from natural gas sources, to identify source signatures specific to natural gas emissions, and to quantify the impacts of these emissions on potential ozone formation and human health. Measurement campaigns were conducted in two natural gas production regions: the Denver-Julesburg Basin in northeast Colorado and the Marcellus Shale region surrounding Pittsburgh, Pennsylvania. An informal measurement intercomparison validated the canister sampling methodology used throughout this dissertation for the measurement of oxygenated VOCs. Mixing ratios of many VOCs measured during both campaigns were similar to or higher than those observed in polluted cities. Fluxes of natural gas-associated VOCs in Colorado ranged from 1.5-3 times industry estimates. Similar emission ratios relative to propane were observed for C2-C6 alkanes in both regions, and an isopentane:n-pentane ratio ≈1 was identified as a unique tracer for natural gas emissions. Source apportionment estimates indicated that natural gas emissions were responsible for the majority of C2-C8 alkanes observed in each region, but accounted for a small proportion of alkenes and aromatic compounds. Natural gas emissions in both regions accounted for approximately 20% of hydroxyl radical reactivity, which could hinder federal ozone standard

  17. Petroleum geology of Kela-2, the most productive gas field in China

    Energy Technology Data Exchange (ETDEWEB)

    Chengzao, Jia [PetroChina Company Limited, Beijing 100011 (China); Qiming, Li [Research Institute of Petroleum Exploration and Development (RIPED), PetroChina, Beijing 100083 (China)

    2008-04-15

    The Kela-2 gas field, located in the Kuqa Depression of Tarim Basin, is the most productive gas field in China, based on per unit surface acreage. The gas trap is a subsurface anticline formed along an E-W trending thrust belt in front of the southern Tianshan Mountains. The gas pay zones are located in fine-grained sandstones of a fan delta front facies in the Lower Cretaceous Bashijiqik Formation (K{sub l}bs), and Eogene evaporitic rocks serve as regional cap rocks. The gases were derived primarily from over-mature Jurassic coal measures. Peak gas generation and final shaping of the Kela-2 structure occurred relatively late, in the late Himalayan orogeny (5-0 Ma). Thrust faulting appears to have played a significant role in the hydrocarbon generation, migration, accumulation and preservation in this foreland basin. Detailed delineation of the Kela-2 gas field indicates that high-quality regional cap rocks are essential for the formation of the super-rich, abnormally pressured, giant gas fields, while buried anticlines under the overthrust zone are the favorable gas habitat. Late gas accumulation is considered to be decisive for the conservation of the giant gas fields. (author)

  18. Partial Oxidation Gas Turbine for Power and Hydrogen Co-Production from Coal-Derived Fuel in Industrial Applications

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Rabovitser

    2009-06-30

    , pressures, and volumetric flows practically identical. In POGT mode, the turbine specific power (turbine net power per lb mass flow from expander exhaust) is twice the value of the onventional turbine. POGT based IGCC plant conceptual design was developed and major components have been identified. Fuel flexible fluid bed gasifier, and novel POGT unit are the key components of the 100 MW IGCC plant for co producing electricity, hydrogen and/or yngas. Plant performances were calculated for bituminous coal and oxygen blown versions. Various POGT based, natural gas fueled systems for production of electricity only, coproduction of electricity and hydrogen, and co production of electricity and syngas for gas to liquid and hemical processes were developed and evaluated. Performance calculations for several versions of these systems were conducted. 64.6 % LHV efficiency for fuel to electricity in combined cycle was achieved. Such a high efficiency arise from using of syngas from POGT exhaust s a fuel that can provide required temperature level for superheated steam generation in HRSG, as well as combustion air preheating. Studies of POGT materials and combustion instabilities in POR were conducted and results reported. Preliminary market assessment was performed, and recommendations for POGT systems applications in oil industry were defined. POGT technology is ready to proceed to the engineering prototype stage, which is recommended.

  19. Review of Slug Detection, Modeling and Control Techniques for Offshore Oil & Gas Production Processes

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2015-01-01

    The current offshore oil & gas multi-phase production and transportation installations have big challenges related with the slugging flow: An unstable multi-phase flow regime where the flow rates, pressures and temperatures oscillate in the considered processes. Slug can be caused by different...... of these methods can simultaneously reduce the oil & gas production, which is a very big concern as the production rate is the key evaluation parameter for offshore production. We conclude that the slugging flow is a well-defined phenomenon, even though this subject has been extensively investigated in the past...... operating conditions and installation structures. The most severe slugs are often induced in long vertical risers or production wells, where liquid blocks gas at the riser/well base and correspondingly it causes the pressure to accumulate and hence originates the oscillating performance. There are many...

  20. The Influence of Allocation on the Carbon Footprint of Electricity Production from Waste Gas, a Case Study for Blast Furnace Gas

    Directory of Open Access Journals (Sweden)

    Joeri Van Mierlo

    2013-03-01

    Full Text Available Producing electricity from waste gas is an after treatment for waste gas while recovering the energy content. This paper addresses the methodology to calculate the effect that waste gas energy recovery has on lowering the impact of climate change. Greenhouse gases are emitted while burning the waste gas. However, a thorough study should include the production of the feedstock as well as the production of the infrastructure. A framework is developed to calculate the environmental impact of electricity production from waste gas with a life cycle approach. The present paper has a twofold purpose: to assess the climate change impact of generating electricity with blast furnace gas (BFG as a waste gas from the steel industry; and to establish a sensitivity assessment of the environmental implications of different allocation rules.

  1. Maximizing the resources by managing the risks among oil, gas and coal production

    Energy Technology Data Exchange (ETDEWEB)

    Nofti, Bakhtiar; Imantyoko, Agung; Adnan, Alkifli [Pertamina EP (Indonesia)

    2011-07-01

    Indonesia's fossil fuel reserves are quite large, in line with its high fossil energy consumption. Production of oil and gas usually takes place in different areas from those where coal is mined, but there is some overlap. The government's intention is to produce energy from all fossil fuels to sustain economic stability. This is a complex task because oil and gas and coal mining are two distinct sectors. There are various issues involved, such as mining zone restrictions, funding and health and safety. This paper presents the idea of maximizing resources by managing risks among oil, gas and coal production. Tapian is one the great success stories of how the government successfully undertook the exploration and production of oil, gas and coal simultaneously while managing and coordinating all the risks involved. The study demonstrates that it is possible to overlap land mines in a harmonious way and that the problems involved can be mitigated.

  2. Characterization of Gas Flaring in North Dakota using the Satellite Data Product, VIIRS Nightfire

    Science.gov (United States)

    Baugh, K.

    2015-12-01

    Oil production in the North Dakota, USA Bakken Formation has increased dramatically over the last decade. The natural gas associated with this oil production is typically burned off, or flared, if there does not exist infrastructure to transport the natural gas to market. This flaring activity can be characterized using the satellite Nightfire data product, generated at NOAA NCEI. Nightfire uses nighttime data from the infrared bands of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument, onboard the Suomi National Polar-orbiting Partnership (NPP) platform, and identifies hotspots at the time of overpass. In addition, Nightfire gives estimates of the temperature, size, and radiant heat of the hotspots. This presentation will show the spatial and temporal distribution of gas flaring in North Dakota from 2012-2015. In addition, a summary of calibration work to estimate flared gas volumes from Nightfire detections will be presented.

  3. Pyrolysis of glycerol for the production of hydrogen or syn gas.

    Science.gov (United States)

    Valliyappan, T; Bakhshi, N N; Dalai, A K

    2008-07-01

    Biodiesel has high potential as alternative liquid transportation fuel because it is renewable and CO(2) neutral, and has similar properties as diesel fuel. Glycerol is a by-product obtained during the production of biodiesel. Canadian government has planned to produce 500 million litres of biodiesel by 2010. An increase in biodiesel production would decrease the market price of glycerol. The objective of this study is to pyrolyse glycerol for the production of clean fuels such as H(2) or a feedstock such as syn gas for additional transportation fuel via Fisher-Tropsch synthesis. The pyrolysis of glycerol was carried out at various flow rates of N(2) (30-70 mL/min), temperatures (650-800 degrees C) and types and sizes of packing material in a tubular reactor at atmospheric pressure. The products were mostly gas, essentially consisting of CO, H(2), CO(2), CH(4) and C(2)H(4). It was observed that temperature, carrier flow rates and particle diameter of packing material had profound effects on the conversion of glycerol as well as product distribution. Composition of product gas ranged between syn gas 70-93 mol%, CH(4) 3-15 mol% and C(2)H(4) 2-12 mol% and heating value ranged from 13 to 22 MJ/m(3). This study indicates that the bio-glycerol has potential in making syn gas and medium heating value gases.

  4. Projecting the CO2 and Climatic Change Effects on the Net Primary Productivity of the Urban Ecosystems in Phoenix, AZ in the 21st Century under Multiple RCP (Representative Concentration Pathway) Scenarios

    National Research Council Canada - National Science Library

    Chunbo Chen; Chi Zhang

    2017-01-01

    .... As a key indicator of ecological health, net primary productivity (NPP) provides valuable information about the performance of urban ecosystem in response to the changes in urban climate and atmosphere in the 21st century...

  5. Analysis of Devonian Black Shales in Kentucky for Potential Carbon Dioxide Sequestration and Enhanced Natural Gas Production

    Energy Technology Data Exchange (ETDEWEB)

    Brandon C. Nuttall; Cortland F. Eble; James A. Drahovzal; R. Marc Bustin

    2005-09-30

    Carbonaceous (black) Devonian gas shales underlie approximately two-thirds of Kentucky. In these shales, natural gas occurs in the intergranular and fracture porosity and is adsorbed on clay and kerogen surfaces. This is analogous to methane storage in coal beds, where CO2 is preferentially adsorbed, displacing methane. Black shales may similarly desorb methane in the presence of CO2. Drill cuttings from the Kentucky Geological Survey Well Sample and Core Library were sampled to determine both CO2 and CH4 adsorption isotherms. Sidewall core samples were acquired to investigate CO2 displacement of methane. An elemental capture spectroscopy log was acquired to investigate possible correlations between adsorption capacity and mineralogy. Average random vitrinite reflectance data range from 0.78 to 1.59 (upper oil to wet gas and condensate hydrocarbon maturity range). Total organic content determined from acid-washed samples ranges from 0.69 to 14 percent. CO2 adsorption capacities at 400 psi range from a low of 14 scf/ton in less organic-rich zones to more than 136 scf/ton in the more organic-rich zones. There is a direct linear correlation between measured total organic carbon content and the adsorptive capacity of the shale; CO2 adsorption capacity increases with increasing organic carbon content. Initial volumetric estimates based on these data indicate a CO2 sequestration capacity of as much as 28 billion tons total in the deeper and thicker parts of the Devonian shales in Kentucky. In the Big Sandy Gas Field area of eastern Kentucky, calculations using the net thickness of shale with 4 percent or greater total organic carbon, indicate that 6.8 billion tonnes of CO2 could be sequestered in the five county area. Discounting the uncertainties in reservoir volume and injection efficiency, these results indicate that the black shales of Kentucky are a potentially large geologic sink for CO2. Moreover, the extensive occurrence of gas shales in Paleozoic and Mesozoic

  6. MODELLING OF THE GAS DIFFUSION IN FLEXIBLE PIPELINES FOR OIL & GAS PRODUCTION

    Directory of Open Access Journals (Sweden)

    Marius STAN

    2017-05-01

    Full Text Available This presentation describes a model used to study gas diffusion through layers of flexible pipes by time. The temperature gradient pipe is considered as temperature dependent permeability rates. This model is coupled with a calculation that indicate changes in pressure and volume of vapors resulting in the annular space. Associated mathematical models and methods for solving the results obtained are presented in Math Soft with a user-friendly interface that helps in data entry and processing results. In this presentation will show the possibilities of this software.

  7. An optimization methodology for the design of renewable energy systems for residential net zero energy buildings with on-site heat production

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2011-01-01

    energy supply systems for residential NZEB involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system......The concept of net zero energy buildings (NZEB) has received increased attention throughout the last years. A well adapted and optimized design of the energy supply system is crucial for the performance of such buildings. This paper aims at developing a method for the optimal sizing of renewable...

  8. European energy security. An analysis of future Russian natural gas production and exports

    Energy Technology Data Exchange (ETDEWEB)

    Soederbergh, Bengt; Jakobsson, Kristofer; Aleklett, Kjell [Global Energy Systems, Department of Physics and Astronomy, Uppsala University, Laegerhyddsvaegen 1, Box 535, SE-751 21, Uppsala (Sweden)

    2010-12-15

    The widening gap between EU gas production and consumption may require an 87% increase of import volumes between 2006 and 2030, and there are great uncertainties regarding the amounts of gas that can be expected from new suppliers. The potential of increased production from Norway and Algeria is limited; hence, Russia is likely to play a crucial part of meeting the anticipated growing gas demand of the EU. A field-by-field study of 83 giant gas fields shows that the major producing Russian gas fields are in decline, and by 2013 much larger supplies from the Yamal Peninsula and the Shtokman field will be needed in order to avoid a decline in production. Gas from fields in Eastern Siberia and the Far East will mainly be directed to the Asian and Pacific Rim markets, thereby limiting its relevance to the European and CIS markets. As a result, the maximum export increase to the European and CIS markets amounts only to about 45% for the period 2015-2030. The discourse surrounding the EU's dependence on Russian gas should thus not only be concerned with geopolitics, but also with the issue of resource limitations. (author)

  9. Potential restrictions for CO2 sequestration sites due to shale and tight gas production.

    Science.gov (United States)

    Elliot, T R; Celia, M A

    2012-04-03

    Carbon capture and geological sequestration is the only available technology that both allows continued use of fossil fuels in the power sector and reduces significantly the associated CO(2) emissions. Geological sequestration requires a deep permeable geological formation into which captured CO(2)can be injected, and an overlying impermeable formation, called a caprock, that keeps the buoyant CO(2) within the injection formation. Shale formations typically have very low permeability and are considered to be good caprock formations. Production of natural gas from shale and other tight formations involves fracturing the shale with the explicit objective to greatly increase the permeability of the shale. As such, shale gas production is in direct conflict with the use of shale formations as a caprock barrier to CO(2) migration. We have examined the locations in the United States where deep saline aquifers, suitable for CO(2) sequestration, exist, as well as the locations of gas production from shale and other tight formations. While estimated sequestration capacity for CO(2) sequestration in deep saline aquifers is large, up to 80% of that capacity has areal overlap with potential shale-gas production regions and, therefore, could be adversely affected by shale and tight gas production. Analysis of stationary sources of CO(2) shows a similar effect: about two-thirds of the total emissions from these sources are located within 20 miles of a deep saline aquifer, but shale and tight gas production could affect up to 85% of these sources. These analyses indicate that colocation of deep saline aquifers with shale and tight gas production could significantly affect the sequestration capacity for CCS operations. This suggests that a more comprehensive management strategy for subsurface resource utilization should be developed.

  10. Economic perspectives of Power-to-Gas technologies in bio-methane production

    NARCIS (Netherlands)

    Sarić, Marija; Dijkstra, Jan Wilco; Haije, W.G.

    2017-01-01

    A study on integration of Power-to-Gas technology with bio-methane production from bio-syngas produced by biomass gasification shows that a significant amount of excess electricity can be accommodated in bio-SNG production. By adding hydrogen produced from intermittent renewable sources to a

  11. Enhancement of carbon dioxide reduction and methane production by an obligate anaerobe and gas dissolution device.

    Science.gov (United States)

    Kim, Seungjin; Choi, Kwangkeun; Kim, Jong-Oh; Chung, Jinwook

    2016-01-25

    The use of gas dissolution devices to improve the efficiency of H2 dissolution has enhanced CO2 reduction and CH4 production. In addition, the nutrients that initially existed in anaerobic sludge were exhausted over time, and the activities of anaerobic microorganisms declined. When nutrients were artificially injected, CO2 reduction and CH4 production rates climbed. Thus, assuming that the activity of the obligatory anaerobic microorganisms is maintained, a gas dissolution device will further enhance the efficiency of CO2 reduction and CH4 production. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Natural gas hydrates : development and test of innovative methods for gas production from hydrate-bearing sediments

    Energy Technology Data Exchange (ETDEWEB)

    Schicks, J.M.; Spangenberg, E.; Steinhauer, B.; Klump, J.; Giese, R.; Erzinger, J. [German Research Centre for Geosciences, Potsdam (Germany). Helmholtz Centre; Haeckel, M.; Bigalke, N.; Savy, J.P.; Kossel, E.; Deusner, C.; Wallmann, K. [Leibniz Inst. of Marine Sciences (Germany)

    2010-07-01

    This paper discussed a German project conducted to determine the stability of natural gas hydrates during methane production activities. The Submarine Gas Hydrate Reservoirs (SUGAR) project was established to determine depressurization, thermal stimulation, and chemical addition reaction routes for gas hydrates. A heat exchange reactor was used to test for the catalytic oxidation of methane. A large-scale